TaskManagerQuartzImpl.java

/*
 * Copyright (c) 2010-2017 Evolveum
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.evolveum.midpoint.task.quartzimpl;

import static com.evolveum.midpoint.schema.result.OperationResultStatus.IN_PROGRESS;
import static com.evolveum.midpoint.schema.result.OperationResultStatus.SUCCESS;
import static com.evolveum.midpoint.schema.result.OperationResultStatus.UNKNOWN;
import static java.util.Collections.singleton;

import java.text.ParseException;
import java.util.*;
import java.util.concurrent.CancellationException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.function.Function;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.xml.datatype.Duration;
import javax.xml.datatype.XMLGregorianCalendar;

import com.evolveum.midpoint.prism.ItemDefinition;
import com.evolveum.midpoint.prism.delta.builder.DeltaBuilder;
import com.evolveum.midpoint.repo.api.PreconditionViolationException;
import com.evolveum.midpoint.task.api.*;
import com.evolveum.midpoint.task.quartzimpl.handlers.PartitioningTaskHandler;
import com.evolveum.midpoint.task.quartzimpl.work.WorkStateManager;
import com.evolveum.midpoint.task.quartzimpl.work.workers.WorkersManager;
import com.evolveum.midpoint.xml.ns._public.common.common_3.*;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.lang.Validate;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.quartz.JobKey;
import org.quartz.Scheduler;
import org.quartz.SchedulerException;
import org.quartz.Trigger;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.DependsOn;
import org.springframework.stereotype.Service;

import com.evolveum.midpoint.common.configuration.api.MidpointConfiguration;
import com.evolveum.midpoint.prism.PrismContext;
import com.evolveum.midpoint.prism.PrismObject;
import com.evolveum.midpoint.prism.PrismObjectDefinition;
import com.evolveum.midpoint.prism.delta.ItemDelta;
import com.evolveum.midpoint.prism.path.ItemPath;
import com.evolveum.midpoint.prism.polystring.PolyString;
import com.evolveum.midpoint.prism.query.ObjectQuery;
import com.evolveum.midpoint.prism.query.builder.QueryBuilder;
import com.evolveum.midpoint.prism.query.builder.S_AtomicFilterEntry;
import com.evolveum.midpoint.prism.xml.XmlTypeConverter;
import com.evolveum.midpoint.repo.api.RepositoryService;
import com.evolveum.midpoint.schema.GetOperationOptions;
import com.evolveum.midpoint.schema.ResultHandler;
import com.evolveum.midpoint.schema.SearchResultList;
import com.evolveum.midpoint.schema.SearchResultMetadata;
import com.evolveum.midpoint.schema.SelectorOptions;
import com.evolveum.midpoint.schema.result.OperationResult;
import com.evolveum.midpoint.schema.result.OperationResultStatus;
import com.evolveum.midpoint.security.api.SecurityContextManager;
import com.evolveum.midpoint.task.quartzimpl.cluster.ClusterManager;
import com.evolveum.midpoint.task.quartzimpl.cluster.ClusterStatusInformation;
import com.evolveum.midpoint.task.quartzimpl.execution.ExecutionManager;
import com.evolveum.midpoint.task.quartzimpl.execution.StalledTasksWatcher;
import com.evolveum.midpoint.util.exception.ObjectAlreadyExistsException;
import com.evolveum.midpoint.util.exception.ObjectNotFoundException;
import com.evolveum.midpoint.util.exception.SchemaException;
import com.evolveum.midpoint.util.exception.SystemException;
import com.evolveum.midpoint.util.logging.LoggingUtils;
import com.evolveum.midpoint.util.logging.Trace;
import com.evolveum.midpoint.util.logging.TraceManager;
import com.evolveum.prism.xml.ns._public.types_3.PolyStringType;

/**
 * Task Manager implementation using Quartz scheduler.
 *
 * Main classes:
 *  - TaskManagerQuartzImpl
 *  - TaskQuartzImpl
 *
 * Helper classes:
 *  - ExecutionManager: node-related functions (start, stop, query status), task-related functions (stop, query status)
 *    - LocalNodeManager and RemoteExecutionManager (specific methods for local node and remote nodes)
 *
 *  - TaskManagerConfiguration: access to config gathered from various places (midpoint config, sql repo config, system properties)
 *  - ClusterManager: keeps cluster nodes synchronized and verifies cluster configuration sanity
 *  - JmxClient: used to invoke remote JMX agents
 *  - JmxServer: provides a JMX agent for midPoint
 *  - TaskSynchronizer: synchronizes information about tasks between midPoint repo and Quartz Job Store
 *  - Initializer: contains TaskManager initialization code (quite complex)
 *
 * @author Pavol Mederly
 *
 */
@Service(value = "taskManager")
@DependsOn(value="repositoryService")
public class TaskManagerQuartzImpl implements TaskManager, BeanFactoryAware {

    private static final String DOT_INTERFACE = TaskManager.class.getName() + ".";
    private static final String DOT_IMPL_CLASS = TaskManagerQuartzImpl.class.getName() + ".";
    private static final String CLEANUP_TASKS = DOT_INTERFACE + "cleanupTasks";
	public static final String CONTENTION_LOG_NAME = TaskManagerQuartzImpl.class.getName() + ".contention";

    @Autowired
    private TaskManagerConfiguration configuration;

    // instances of all the helper classes (see their definitions for their description)
    private ExecutionManager executionManager = new ExecutionManager(this);
    private ClusterManager clusterManager = new ClusterManager(this);
    private StalledTasksWatcher stalledTasksWatcher = new StalledTasksWatcher(this);

    // task handlers (mapped from their URIs)
    private Map<String,TaskHandler> handlers = new HashMap<>();

	private final Set<TaskDeletionListener> taskDeletionListeners = new HashSet<>();

    // cached task prism definition
	private PrismObjectDefinition<TaskType> taskPrismDefinition;

    // error status for this node (local Quartz scheduler is not allowed to be started if this status is not "OK")
    private NodeErrorStatusType nodeErrorStatus = NodeErrorStatusType.OK;

    // task listeners
    private Set<TaskListener> taskListeners = new HashSet<>();

    /**
     * Registered transient tasks. Here we put all transient tasks that are to be managed by the task manager.
     * Planned use:
     * 1) all transient subtasks of persistent tasks (e.g. for parallel import/reconciliation)
     * 2) all transient tasks that have subtasks (e.g. for planned parallel provisioning operations)
     * However, currently we support only case #1, and we store LAT information directly in the parent task.
     */
    //private Map<String,TaskQuartzImpl> registeredTransientTasks = new HashMap<>();          // key is the lightweight task identifier

    // locally running task instances - here are EXACT instances of TaskQuartzImpl that are used to execute handlers.
    // Use ONLY for those actions that need to work with these instances, e.g. when calling heartbeat() methods on them.
    // For any other business please use LocalNodeManager.getLocallyRunningTasks(...).
    // Maps task id -> task
    private final HashMap<String,TaskQuartzImpl> locallyRunningTaskInstancesMap = new HashMap<>();

    private ExecutorService lightweightHandlersExecutor = Executors.newCachedThreadPool();

	private BeanFactory beanFactory;

    @Autowired private MidpointConfiguration midpointConfiguration;
	@Autowired private RepositoryService repositoryService;
	@Autowired private LightweightIdentifierGenerator lightweightIdentifierGenerator;
	@Autowired private PrismContext prismContext;
	@Autowired private WorkStateManager workStateManager;
	@Autowired private WorkersManager workersManager;

	@Autowired
	@Qualifier("securityContextManager")
	private SecurityContextManager securityContextManager;

    private static final transient Trace LOGGER = TraceManager.getTrace(TaskManagerQuartzImpl.class);

    // how long to wait after TaskManager shutdown, if using JDBC Job Store (in order to give the jdbc thread pool a chance
    // to close, before embedded H2 database server would be closed by the SQL repo shutdown procedure)
    //
    // the fact that H2 database is embedded is recorded in the 'databaseIsEmbedded' configuration flag
    // (see shutdown() method)
    private static final long WAIT_ON_SHUTDOWN = 2000;

	private List<String> PURGE_SUCCESSFUL_RESULT_FOR = Collections.singletonList(TaskCategory.WORKFLOW);

	//region Initialization and shutdown
    // ********************* INITIALIZATION AND SHUTDOWN *********************

    /**
     * Initialization.
     *
     * TaskManager can work in two modes:
     *  - "stop on initialization failure" - it means that if TaskManager initialization fails, the midPoint will
     *    not be started (implemented by throwing SystemException). This is a safe approach, however, midPoint could
     *    be used also without Task Manager, so it is perhaps too harsh to do it this way.
     *  - "continue on initialization failure" - after such a failure midPoint initialization simply continues;
     *    however, task manager is switched to "Error" state, in which the scheduler cannot be started;
     *    Moreover, actually almost none Task Manager methods can be invoked, to prevent a damage.
     *
     *    This second mode is EXPERIMENTAL, should not be used in production for now.
     *
     *  ---
     *  So,
     *
     *  (A) Generally, when not initialized, we refuse to execute almost all operations (knowing for sure that
     *  the scheduler is not running).
     *
     *  (B) When initialized, but in error state (typically because of cluster misconfiguration not related to this node),
     *  we refuse to start the scheduler on this node. Other methods are OK.
     *
     */

    @PostConstruct
    public void init() {

        OperationResult result = createOperationResult("init");

        try {
            new Initializer(this).init(result);
        } catch (TaskManagerInitializationException e) {
            LoggingUtils.logUnexpectedException(LOGGER, "Cannot initialize TaskManager due to the following exception: ", e);
            throw new SystemException("Cannot initialize TaskManager", e);
        }

        // if running in test mode, the postInit will not be executed... so we have to start scheduler here
        if (configuration.isTestMode()) {
            postInit(result);
        }
    }

    @Override
    public void postInit(OperationResult parentResult) {

        OperationResult result = parentResult.createSubresult(DOT_IMPL_CLASS + "postInit");

        if (!configuration.isTestMode()) {
            clusterManager.startClusterManagerThread();
        }

        if (configuration.isSchedulerInitiallyStopped()) {
        	LOGGER.info("Scheduler was not started because of system configuration 'schedulerInitiallyStopped' setting. You can start it manually if needed.");
		} else if (midpointConfiguration.isSafeMode()) {
			LOGGER.info("Scheduler was not started because the safe mode is ON. You can start it manually if needed.");
		} else {
			executionManager.startScheduler(getNodeId(), result);
			if (result.getLastSubresultStatus() != SUCCESS) {
				throw new SystemException("Quartz task scheduler couldn't be started.");
			}
		}

        result.computeStatus();
    }

    @PreDestroy
    public void shutdown() {

        OperationResult result = createOperationResult("shutdown");

        LOGGER.info("Task Manager shutdown starting");

        if (executionManager.getQuartzScheduler() != null) {

            executionManager.stopScheduler(getNodeId(), result);
            executionManager.stopAllTasksOnThisNodeAndWait(0L, result);

            if (configuration.isTestMode()) {
                LOGGER.info("Quartz scheduler will NOT be shutdown. It stays in paused mode.");
            } else {
                try {
                    executionManager.shutdownLocalScheduler();
                } catch (TaskManagerException e) {
                    LoggingUtils.logUnexpectedException(LOGGER, "Cannot shutdown Quartz scheduler, continuing with node shutdown", e);
                }
            }
        }

        clusterManager.stopClusterManagerThread(0L, result);
        clusterManager.recordNodeShutdown(result);

        if (configuration.isJdbcJobStore() && configuration.isDatabaseIsEmbedded()) {
            LOGGER.trace("Waiting {} msecs to give Quartz thread pool a chance to shutdown.", WAIT_ON_SHUTDOWN);
            try {
                Thread.sleep(WAIT_ON_SHUTDOWN);
            } catch (InterruptedException e) {
                // safe to ignore
            }
        }
        LOGGER.info("Task Manager shutdown finished");
    }

    //endregion

    //region Node state management (???)
    /*
     *  ********************* STATE MANAGEMENT *********************
     */

    public boolean isRunning() {
        return executionManager.isLocalNodeRunning();
    }

    public boolean isInErrorState() {
        return nodeErrorStatus != NodeErrorStatusType.OK;
    }
    //endregion

    //region Suspend, resume, pause, unpause
    /*
    * First here are TaskManager API methods implemented in this class,
    * then those, which are delegated to helper classes.
    */

    @Override
    public boolean deactivateServiceThreads(long timeToWait, OperationResult parentResult) {

        OperationResult result = parentResult.createSubresult(DOT_INTERFACE + "deactivateServiceThreads");
        result.addParam("timeToWait", timeToWait);

        LOGGER.info("Deactivating Task Manager service threads (waiting time = " + timeToWait + ")");
        clusterManager.stopClusterManagerThread(timeToWait, result);
        boolean retval = executionManager.stopSchedulerAndTasksLocally(timeToWait, result);

        result.computeStatus();
        return retval;
    }

    @Override
    public void reactivateServiceThreads(OperationResult parentResult) {

        OperationResult result = parentResult.createSubresult(DOT_INTERFACE + "reactivateServiceThreads");

        LOGGER.info("Reactivating Task Manager service threads.");
        clusterManager.startClusterManagerThread();
        executionManager.startScheduler(getNodeId(), result);

        result.computeStatus();
    }

    @Override
    public boolean getServiceThreadsActivationState() {

        try {
            Scheduler scheduler = executionManager.getQuartzScheduler();
            return scheduler != null && scheduler.isStarted() &&
                    !scheduler.isInStandbyMode() &&
                    !scheduler.isShutdown() &&
                    clusterManager.isClusterManagerThreadActive();
        } catch (SchedulerException e) {
            LoggingUtils.logUnexpectedException(LOGGER, "Cannot determine the state of the Quartz scheduler", e);
            return false;
        }
    }

    @Override
    public boolean suspendTask(Task task, long waitTime, OperationResult parentResult) {
        return suspendTasksResolved(singleton(task), waitTime, false, parentResult);
    }

	@Override
	public boolean suspendAndCloseTask(Task task, long waitTime, OperationResult parentResult) {
		return suspendTasksResolved(singleton(task), waitTime, true, parentResult);
	}

	@Override
    public boolean suspendTasks(Collection<String> taskOids, long waitForStop, OperationResult parentResult) {
        return suspendTasksResolved(resolveTaskOids(taskOids, parentResult), waitForStop, false, parentResult);
    }

    @Override
    public boolean suspendTaskTree(String rootTaskOid, long waitTime, OperationResult parentResult)
		    throws SchemaException, ObjectNotFoundException {
	    OperationResult result = parentResult.createSubresult(DOT_INTERFACE + "suspendTaskTree");
	    result.addParam("rootTaskOid", rootTaskOid);
	    result.addParam("waitTime", waitTime);

	    try {
		    TaskQuartzImpl root = getTask(rootTaskOid, result);
		    List<Task> subtasks = root.listSubtasksDeeply(parentResult);
		    List<String> oidsToSuspend = new ArrayList<>(subtasks.size() + 1);
		    oidsToSuspend.add(rootTaskOid);
		    for (Task subtask : subtasks) {
			    oidsToSuspend.add(subtask.getOid());
		    }
		    return suspendTasks(oidsToSuspend, waitTime, result);
	    } catch (Throwable t) {
	    	result.recordFatalError("Couldn't suspend task tree", t);
	    	throw t;
	    } finally {
	    	result.computeStatusIfUnknown();
	    }
    }

    @Override
    public void resumeTaskTree(String rootTaskOid, OperationResult parentResult) throws SchemaException, ObjectNotFoundException {
	    OperationResult result = parentResult.createSubresult(DOT_INTERFACE + "resumeTaskTree");
	    result.addParam("rootTaskOid", rootTaskOid);

	    try {
		    TaskQuartzImpl root = getTask(rootTaskOid, result);
		    List<Task> subtasks = root.listSubtasks(parentResult);
		    List<String> oidsToResume = new ArrayList<>(subtasks.size() + 1);
		    if (root.getExecutionStatus() == TaskExecutionStatus.SUSPENDED) {
			    oidsToResume.add(rootTaskOid);
		    }
		    for (Task subtask : subtasks) {
			    if (subtask.getExecutionStatus() == TaskExecutionStatus.SUSPENDED) {
				    oidsToResume.add(subtask.getOid());
			    }
		    }
		    resumeTasks(oidsToResume, result);
	    } catch (Throwable t) {
	    	result.recordFatalError("Couldn't resume task tree", t);
	    	throw t;
	    } finally {
	    	result.computeStatusIfUnknown();
	    }
    }

	@Override
	public void reconcileWorkers(String coordinatorTaskOid, WorkersReconciliationOptions options, OperationResult parentResult)
			throws SchemaException, ObjectNotFoundException, ObjectAlreadyExistsException {
		OperationResult result = parentResult.createSubresult(DOT_INTERFACE + "reconcileWorkers");
		result.addParam("coordinatorTaskOid", coordinatorTaskOid);

		try {
			workersManager.reconcileWorkers(coordinatorTaskOid, options, result);
		} catch (Throwable t) {
			result.recordFatalError("Couldn't reconcile workers", t);
			throw t;
		} finally {
			result.computeStatusIfUnknown();
		}
	}

	@Override
	public void scheduleCoordinatorAndWorkersNow(String coordinatorOid, OperationResult parentResult) throws SchemaException, ObjectNotFoundException {
		OperationResult result = parentResult.createSubresult(DOT_INTERFACE + "scheduleCoordinatorAndWorkersNow");
		result.addParam("coordinatorOid", coordinatorOid);
		try {
			TaskQuartzImpl coordinatorTask = getTask(coordinatorOid, result);
			TaskExecutionStatus status = coordinatorTask.getExecutionStatus();
			switch (status) {
				case CLOSED:
				case RUNNABLE:
					// hoping that the task handler will do what is needed (i.e. recreate or restart workers)
					scheduleTaskNow(coordinatorTask, result);
					break;
				case WAITING:
					// this means that workers are either busy (runnable) or are suspended; administrator should do something with that
					String msg1 =
							"Coordinator " + coordinatorTask + " cannot be run now, because it is in WAITING state. " +
									"Please check and resolve state of its worker tasks.";
					LOGGER.error(msg1);
					result.recordFatalError(msg1);
					break;
				case SUSPENDED:
					String msg2 =
							"Coordinator " + coordinatorTask + " cannot be run now, because it is in SUSPENDED state. " +
									"Please use appropriate method to schedule its execution.";
					LOGGER.error(msg2);
					result.recordFatalError(msg2);
					break;
				default:
					throw new IllegalStateException("Coordinator " + coordinatorTask + " is in unsupported state: " + status);
			}
		} catch (Throwable t) {
			result.recordFatalError("Couldn't resume coordinator and its workers", t);
			throw t;
		} finally {
			result.computeStatusIfUnknown();
		}
	}

	private boolean suspendTasksResolved(Collection<Task> tasks, long waitForStop, boolean closeTasks, OperationResult parentResult) {
        OperationResult result = parentResult.createSubresult(DOT_INTERFACE + "suspendTasks");
        result.addArbitraryObjectCollectionAsParam("tasks", tasks);
        result.addParam("waitForStop", waitingInfo(waitForStop));
        result.addParam("closeTasks", closeTasks);

        LOGGER.info("{} tasks {}; {}.", closeTasks ? "Closing" : "Suspending", tasks, waitingInfo(waitForStop));

        for (Task task : tasks) {

            if (task.getOid() == null) {
                // this should not occur; so we can treat it in such a brutal way
                throw new IllegalArgumentException("Only persistent tasks can be suspended/closed (for now); task " + task + " is transient.");
            } else {
	            if (task.getExecutionStatus() == TaskExecutionStatus.WAITING || task.getExecutionStatus() == TaskExecutionStatus.RUNNABLE) {
		            try {
			            List<ItemDelta<?, ?>> itemDeltas = DeltaBuilder.deltaFor(TaskType.class, prismContext)
					            .item(TaskType.F_EXECUTION_STATUS).replace(TaskExecutionStatusType.SUSPENDED)
					            .item(TaskType.F_STATE_BEFORE_SUSPEND).replace(task.getExecutionStatus().toTaskType())
					            .asItemDeltas();
			            ((TaskQuartzImpl) task).applyDeltasImmediate(itemDeltas, result);
		            } catch (ObjectNotFoundException e) {
			            String message = "Cannot suspend task because it does not exist; task = " + task;
			            LoggingUtils.logException(LOGGER, message, e);
		            } catch (SchemaException | ObjectAlreadyExistsException e) {
			            String message = "Cannot suspend task because of an unexpected exception; task = " + task;
			            LoggingUtils.logUnexpectedException(LOGGER, message, e);
		            }
	            }

                executionManager.pauseTaskJob(task, result);
                // even if this will not succeed, by setting the execution status to SUSPENDED we hope the task
                // thread will exit on next iteration (does not apply to single-run tasks, of course)
            }
        }

        boolean stopped = false;
        if (waitForStop != DO_NOT_STOP) {
            stopped = executionManager.stopTasksRunAndWait(tasks, null, waitForStop, true, result);
        }

        if (closeTasks) {
	        for (Task task : tasks) {
	        	try {
			        closeTask(task, result);
			        ((TaskQuartzImpl) task).checkDependentTasksOnClose(parentResult);
		        } catch (ObjectNotFoundException | SchemaException e) {
			        LoggingUtils.logUnexpectedException(LOGGER, "Cannot close suspended task {}", e, task);
		        }
	        }
        }
        result.computeStatus();
        return stopped;
    }

    private String waitingInfo(long waitForStop) {
        if (waitForStop == WAIT_INDEFINITELY) {
            return "stop tasks, and wait for their completion (if necessary)";
        } else if (waitForStop == DO_NOT_WAIT) {
            return "stop tasks, but do not wait";
        } else if (waitForStop == DO_NOT_STOP) {
            return "do not stop tasks";
        } else {
            return "stop tasks and wait " + waitForStop + " ms for their completion (if necessary)";
        }
    }

    // todo: better name for this method

    @Override
    public void pauseTask(Task task, TaskWaitingReason reason, OperationResult parentResult) throws ObjectNotFoundException, SchemaException {

        OperationResult result = parentResult.createSubresult(DOT_INTERFACE + "pauseTask");
        result.addArbitraryObjectAsParam("task", task);

        if (task.getExecutionStatus() != TaskExecutionStatus.RUNNABLE) {
            String message = "Attempted to pause a task that is not in the RUNNABLE state (task = " + task + ", state = " + task.getExecutionStatus();
            LOGGER.error(message);
            result.recordFatalError(message);
            return;
        }
        try {
            ((TaskQuartzImpl) task).setExecutionStatusImmediate(TaskExecutionStatus.WAITING, result);
            ((TaskQuartzImpl) task).setWaitingReasonImmediate(reason, result);
        } catch (ObjectNotFoundException e) {
            String message = "A task cannot be paused, because it does not exist; task = " + task;
            LoggingUtils.logException(LOGGER, message, e);
            throw e;
        } catch (SchemaException e) {
            String message = "A task cannot be paused due to schema exception; task = " + task;
            LoggingUtils.logUnexpectedException(LOGGER, message, e);
            throw e;
        }

        // make the trigger as it should be
        executionManager.synchronizeTask((TaskQuartzImpl) task, result);

        if (result.isUnknown()) {
            result.computeStatus();
        }
    }

    // todo: better name for this method

    @Override
    public void unpauseTask(Task task, OperationResult parentResult)
		    throws ObjectNotFoundException, SchemaException, PreconditionViolationException {

        OperationResult result = parentResult.createSubresult(DOT_INTERFACE + "unpauseTask");
        result.addArbitraryObjectAsParam("task", task);

        // Here can a race condition occur. If the parent was WAITING but has become SUSPENDED in the meanwhile,
	    // this test could pass (seeing WAITING status) but the following unpause action is mistakenly executed
	    // on suspended task, overwriting SUSPENDED status!
	    //
	    // Therefore scheduleWaitingTaskNow and makeWaitingTaskRunnable must make sure the task is (still) waiting.
	    // The closeTask method is OK even if the task has become suspended in the meanwhile.
        if (task.getExecutionStatus() != TaskExecutionStatus.WAITING) {
            String message = "Attempted to unpause a task that is not in the WAITING state (task = " + task + ", state = " + task.getExecutionStatus();
            LOGGER.error(message);
            result.recordFatalError(message);
            return;
        }
        if (task.getHandlerUri() == null) {
		    LOGGER.trace("No handler in task being unpaused - closing it: {}", task);
		    closeTask(task, result);
	        ((TaskQuartzImpl) task).checkDependentTasksOnClose(parentResult);       // TODO
	        result.computeStatusIfUnknown();
	        return;
	    }

	    TaskUnpauseActionType action = getUnpauseAction(task);
        switch (action) {
        	case EXECUTE_IMMEDIATELY:
		        LOGGER.trace("Unpausing task using 'executeImmediately' action (scheduling it now): {}", task);
		        scheduleWaitingTaskNow(task, result);
		        break;
	        case RESCHEDULE:
		        if (task.isCycle()) {
			        LOGGER.trace("Unpausing recurring task using 'reschedule' action (making it runnable): {}", task);
			        makeWaitingTaskRunnable(task, result);
		        } else {
			        LOGGER.trace("Unpausing task using 'reschedule' action (closing it, because the task is single-run): {}", task);
			        closeTask(task, result);
			        ((TaskQuartzImpl) task).checkDependentTasksOnClose(parentResult);       // TODO
		        }
		        break;
	        case CLOSE:
		        LOGGER.trace("Unpausing task using 'close' action: {}", task);
		        closeTask(task, result);
		        ((TaskQuartzImpl) task).checkDependentTasksOnClose(parentResult);       // TODO
		        break;
	        default:
		        throw new IllegalStateException("Unsupported unpause action: " + action);
        }
	    result.computeStatusIfUnknown();
    }

    @NotNull
	private TaskUnpauseActionType getUnpauseAction(Task task) {
		if (task.getUnpauseAction() != null) {
			return task.getUnpauseAction();
		} else if (task.isSingle()) {
			return TaskUnpauseActionType.EXECUTE_IMMEDIATELY;
		} else {
			return TaskUnpauseActionType.RESCHEDULE;
		}
	}

	@Override
    public void resumeTasks(Collection<String> taskOids, OperationResult parentResult) {
        OperationResult result = parentResult.createSubresult(DOT_INTERFACE + "resumeTasks");
        for (String oid : taskOids) {
            try {
                resumeTask(getTask(oid, result), result);
            } catch (ObjectNotFoundException e) {           // result is already updated
                LoggingUtils.logException(LOGGER, "Couldn't resume task with OID {}", e, oid);
            } catch (SchemaException e) {
                LoggingUtils.logUnexpectedException(LOGGER, "Couldn't resume task with OID {}", e, oid);
            }
        }
        result.computeStatus();
    }

    @Override
    public void resumeTask(Task task, OperationResult parentResult) throws ObjectNotFoundException, SchemaException {

        OperationResult result = parentResult.createSubresult(DOT_INTERFACE + "resumeTask");
        result.addArbitraryObjectAsParam("task", task);
        try {

	        if (task.getExecutionStatus() != TaskExecutionStatus.SUSPENDED &&
			        !(task.getExecutionStatus() == TaskExecutionStatus.CLOSED && task.isCycle())) {
		        String message =
				        "Attempted to resume a task that is not in the SUSPENDED state (or CLOSED for recurring tasks) (task = "
						        + task + ", state = " + task.getExecutionStatus();
		        LOGGER.error(message);
		        result.recordFatalError(message);
		        return;
	        }
	        clearTaskOperationResult(task, parentResult);           // see a note on scheduleTaskNow
	        if (task.getStateBeforeSuspend() == TaskExecutionStatusType.WAITING) {
		        List<ItemDelta<?, ?>> itemDeltas = DeltaBuilder.deltaFor(TaskType.class, prismContext)
				        .item(TaskType.F_EXECUTION_STATUS).replace(TaskExecutionStatusType.WAITING)
				        .item(TaskType.F_STATE_BEFORE_SUSPEND).replace()
				        .asItemDeltas();
		        ((TaskQuartzImpl) task).applyDeltasImmediate(itemDeltas, result);
	        } else {
		        List<ItemDelta<?, ?>> itemDeltas = DeltaBuilder.deltaFor(TaskType.class, prismContext)
				        .item(TaskType.F_EXECUTION_STATUS).replace(TaskExecutionStatusType.RUNNABLE)
				        .item(TaskType.F_STATE_BEFORE_SUSPEND).replace()
				        .asItemDeltas();
		        ((TaskQuartzImpl) task).applyDeltasImmediate(itemDeltas, result);
		        executionManager.synchronizeTask((TaskQuartzImpl) task, result);
	        }
        } catch (ObjectAlreadyExistsException t) {
        	result.recordFatalError("Couldn't resume task: " + t.getMessage(), t);
        	throw new IllegalStateException("Unexpected exception while resuming task " + task + ": " + t.getMessage(), t);
        } catch (Throwable t) {
        	result.recordFatalError("Couldn't resume task: " + t.getMessage(), t);
        	throw t;
        } finally {
        	result.computeStatusIfUnknown();
        }
    }

    private void makeWaitingTaskRunnable(Task task, OperationResult result)
		    throws ObjectNotFoundException, SchemaException, PreconditionViolationException {

        try {
            ((TaskQuartzImpl) task).setExecutionStatusImmediate(TaskExecutionStatus.RUNNABLE, TaskExecutionStatusType.WAITING, result);
        } catch (ObjectNotFoundException e) {
            String message = "A task cannot be made runnable, because it does not exist; task = " + task;
            LoggingUtils.logException(LOGGER, message, e);
            throw e;
        } catch (SchemaException | PreconditionViolationException e) {
            String message = "A task cannot be made runnable; task = " + task;
            LoggingUtils.logUnexpectedException(LOGGER, message, e);
            throw e;
        }

        // make the trigger as it should be
        executionManager.synchronizeTask((TaskQuartzImpl) task, result);
    }
    //endregion

    //region Working with task instances (other than suspend/resume)
    /*
     *  ********************* WORKING WITH TASK INSTANCES *********************
     */

	@Override
	public Task createTaskInstance() {
		return createTaskInstance(null);
	}

	@Override
	public Task createTaskInstance(String operationName) {
		LightweightIdentifier taskIdentifier = generateTaskIdentifier();
		return new TaskQuartzImpl(this, taskIdentifier, operationName);
	}

	private LightweightIdentifier generateTaskIdentifier() {
		return lightweightIdentifierGenerator.generate();
	}

    @Override
	@NotNull
    public TaskQuartzImpl createTaskInstance(PrismObject<TaskType> taskPrism, OperationResult parentResult) throws SchemaException {
        return createTaskInstance(taskPrism, null, parentResult);
    }

    @Override
	@NotNull
	public TaskQuartzImpl createTaskInstance(PrismObject<TaskType> taskPrism, String operationName, OperationResult parentResult) throws SchemaException {

        OperationResult result = parentResult.createMinorSubresult(DOT_INTERFACE + "createTaskInstance");
        result.addParam("taskPrism", taskPrism);

		//Note: we need to be Spring Bean Factory Aware, because some repo implementations are in scope prototype
		RepositoryService repoService = (RepositoryService) this.beanFactory.getBean("repositoryService");
		TaskQuartzImpl task = new TaskQuartzImpl(this, taskPrism, repoService, operationName);
		task.resolveOwnerRef(result);
        result.recordSuccessIfUnknown();
		return task;
	}

	@Override
	@NotNull
	public TaskQuartzImpl getTask(String taskOid, OperationResult parentResult) throws ObjectNotFoundException, SchemaException {
		return getTask(taskOid, null, parentResult);
	}

	@Override
	@NotNull
	public TaskQuartzImpl getTask(String taskOid, Collection<SelectorOptions<GetOperationOptions>> options, OperationResult parentResult) throws ObjectNotFoundException, SchemaException {
		OperationResult result = parentResult.createMinorSubresult(DOT_INTERFACE + "getTask");          // todo ... or .createSubresult (without 'minor')?
		result.addParam(OperationResult.PARAM_OID, taskOid);
		result.addArbitraryObjectCollectionAsParam(OperationResult.PARAM_OPTIONS, options);
		result.addContext(OperationResult.CONTEXT_IMPLEMENTATION_CLASS, TaskManagerQuartzImpl.class);

		TaskQuartzImpl task;
		try {
			PrismObject<TaskType> taskPrism = repositoryService.getObject(TaskType.class, taskOid, options, result);
            task = createTaskInstance(taskPrism, result);
        } catch (ObjectNotFoundException e) {
			result.recordFatalError("Task not found", e);
			throw e;
		} catch (SchemaException e) {
			result.recordFatalError("Task schema error: "+e.getMessage(), e);
			throw e;
		}

		result.recordSuccess();
		return task;
	}

    @Override
	public void switchToBackground(final Task task, OperationResult parentResult) {

		parentResult.recordStatus(OperationResultStatus.IN_PROGRESS, "Task switched to background");
		OperationResult result = parentResult.createSubresult(DOT_INTERFACE + "switchToBackground");

        // if the task result was unknown, we change it to 'in-progress'
        // (and roll back this change if storing into repo fails...)
        boolean wasUnknown = false;
		try {
            if (task.getResult().isUnknown()) {
                wasUnknown = true;
                task.getResult().recordInProgress();
            }
			persist(task, result);
            result.recordSuccess();
        } catch (RuntimeException ex) {
            if (wasUnknown) {
                task.getResult().recordUnknown();
            }
			result.recordFatalError("Unexpected problem: "+ex.getMessage(),ex);
			throw ex;
		}
	}

	private void persist(Task task, OperationResult parentResult) {
		if (task.getPersistenceStatus() == TaskPersistenceStatus.PERSISTENT) {
			// Task already persistent. Nothing to do.
			return;
		}

        TaskQuartzImpl taskImpl = (TaskQuartzImpl) task;

        if (task.getName() == null) {
        	PolyStringType polyStringName = new PolyStringType("Task " + task.getTaskIdentifier());
            taskImpl.setNameTransient(polyStringName);
        }

        if (taskImpl.getOid() != null) {
			// We don't support user-specified OIDs
			throw new IllegalArgumentException("Transient task must not have OID (task:"+task+")");
		}

        // hack: set Category if it is not set yet
        if (taskImpl.getCategory() == null) {
            taskImpl.setCategoryTransient(taskImpl.getCategoryFromHandler());
        }

//		taskImpl.setPersistenceStatusTransient(TaskPersistenceStatus.PERSISTENT);

		// Make sure that the task has repository service instance, so it can fully work as "persistent"
    	if (taskImpl.getRepositoryService() == null) {
			RepositoryService repoService = (RepositoryService) this.beanFactory.getBean("repositoryService");
			taskImpl.setRepositoryService(repoService);
		}

		try {
			addTaskToRepositoryAndQuartz(taskImpl, parentResult);
		} catch (ObjectAlreadyExistsException ex) {
			// This should not happen. If it does, it is a bug. It is OK to convert to a runtime exception
			throw new IllegalStateException("Got ObjectAlreadyExistsException while not expecting it (task:"+task+")",ex);
		} catch (SchemaException ex) {
			// This should not happen. If it does, it is a bug. It is OK to convert to a runtime exception
			throw new IllegalStateException("Got SchemaException while not expecting it (task:"+task+")",ex);
		}
	}

	@Override
	public String addTask(PrismObject<TaskType> taskPrism, OperationResult parentResult) throws ObjectAlreadyExistsException, SchemaException {
        OperationResult result = parentResult.createSubresult(DOT_INTERFACE + "addTask");
		Task task = createTaskInstance(taskPrism, result);			// perhaps redundant, but it's more convenient to work with Task than with Task prism
        if (task.getTaskIdentifier() == null) {
            task.getTaskPrismObject().asObjectable().setTaskIdentifier(generateTaskIdentifier().toString());
        }
		String oid = addTaskToRepositoryAndQuartz(task, result);
        result.computeStatus();
        return oid;
	}

	private String addTaskToRepositoryAndQuartz(Task task, OperationResult parentResult) throws ObjectAlreadyExistsException, SchemaException {

        if (task.isLightweightAsynchronousTask()) {
            throw new IllegalStateException("A task with lightweight task handler cannot be made persistent; task = " + task);
            // otherwise, there would be complications on task restart: the task handler is not stored in the repository,
            // so it is just not possible to restart such a task
        }

        OperationResult result = parentResult.createSubresult(DOT_IMPL_CLASS + "addTaskToRepositoryAndQuartz");
        result.addArbitraryObjectAsParam("task", task);

		PrismObject<TaskType> taskPrism = task.getTaskPrismObject();
        String oid;
        try {
		     oid = repositoryService.addObject(taskPrism, null, result);
        } catch (ObjectAlreadyExistsException | SchemaException e) {
            result.recordFatalError("Couldn't add task to repository: " + e.getMessage(), e);
            throw e;
        }

		((TaskQuartzImpl) task).setOid(oid);

		synchronizeTaskWithQuartz((TaskQuartzImpl) task, result);

        result.computeStatus();
		return oid;
	}

    @Override
    public void modifyTask(String oid, Collection<? extends ItemDelta> modifications, OperationResult parentResult) throws ObjectNotFoundException,
            SchemaException, ObjectAlreadyExistsException {
        OperationResult result = parentResult.createSubresult(DOT_INTERFACE + "modifyTask");
        try {
		    repositoryService.modifyObject(TaskType.class, oid, modifications, result);
            TaskQuartzImpl task = getTask(oid, result);
            task.setRecreateQuartzTrigger(true);
            synchronizeTaskWithQuartz(task, result);
        } finally {
            result.computeStatusIfUnknown();
        }
    }

    @Override
    public void suspendAndDeleteTasks(Collection<String> taskOids, long suspendTimeout, boolean alsoSubtasks, OperationResult parentResult) {

        OperationResult result = parentResult.createSubresult(DOT_INTERFACE + "suspendAndDeleteTasks");
        result.addArbitraryObjectCollectionAsParam("taskOids", taskOids);

        List<Task> tasksToBeDeleted = new ArrayList<>();
        for (String oid : taskOids) {
            try {
                Task task = getTask(oid, result);
                tasksToBeDeleted.add(task);
                if (alsoSubtasks) {
                    tasksToBeDeleted.addAll(task.listSubtasksDeeply(result));
                }
            } catch (ObjectNotFoundException e) {
                // just skip suspending/deleting this task. As for the error, it should be already put into result.
                LoggingUtils.logException(LOGGER, "Error when retrieving task {} or its subtasks before the deletion. Skipping the deletion for this task.", e, oid);
            } catch (SchemaException e) {
                // same as above
                LoggingUtils.logUnexpectedException(LOGGER, "Error when retrieving task {} or its subtasks before the deletion. Skipping the deletion for this task.", e, oid);
            } catch (RuntimeException e) {
                result.createSubresult(DOT_IMPL_CLASS + "getTaskTree").recordPartialError("Unexpected error when retrieving task tree for " + oid + " before deletion", e);
                LoggingUtils.logUnexpectedException(LOGGER, "Unexpected error when retrieving task {} or its subtasks before the deletion. Skipping the deletion for this task.", e, oid);
            }
        }

        List<Task> tasksToBeSuspended = new ArrayList<>();
        for (Task task : tasksToBeDeleted) {
            if (task.getExecutionStatus() == TaskExecutionStatus.RUNNABLE) {
                tasksToBeSuspended.add(task);
            }
        }

        // now suspend the tasks before deletion
        if (!tasksToBeSuspended.isEmpty()) {
            suspendTasksResolved(tasksToBeSuspended, suspendTimeout, false, result);
        }

        // delete them
        for (Task task : tasksToBeDeleted) {
            try {
                deleteTask(task.getOid(), result);
            } catch (ObjectNotFoundException e) {   // in all cases (even RuntimeException) the error is already put into result
                LoggingUtils.logException(LOGGER, "Error when deleting task {}", e, task);
            } catch (SchemaException | RuntimeException e) {
                LoggingUtils.logUnexpectedException(LOGGER, "Error when deleting task {}", e, task);
            }
		}

        if (result.isUnknown()) {
            result.computeStatus();
        }
    }

    @Override
    public void deleteTask(String oid, OperationResult parentResult) throws ObjectNotFoundException, SchemaException {
        OperationResult result = parentResult.createSubresult(DOT_INTERFACE + "deleteTask");
        result.addParam("oid", oid);
        try {
            Task task = getTask(oid, result);
            if (task.getNode() != null) {
                result.recordWarning("Deleting a task that seems to be currently executing on node " + task.getNode());
            }
			for (TaskDeletionListener listener : taskDeletionListeners) {
				listener.onTaskDelete(task, result);
			}
            repositoryService.deleteObject(TaskType.class, oid, result);
            executionManager.removeTaskFromQuartz(oid, result);
            result.computeStatusIfUnknown();
        } catch (ObjectNotFoundException e) {
            result.recordFatalError("Cannot delete the task because it does not exist.", e);
            throw e;
        } catch (SchemaException e) {
            result.recordFatalError("Cannot delete the task because of schema exception.", e);
            throw e;
        } catch (RuntimeException e) {
            result.recordFatalError("Cannot delete the task because of a runtime exception.", e);
            throw e;
        }
    }

    public void registerRunningTask(TaskQuartzImpl task) {
        synchronized (locallyRunningTaskInstancesMap) {
            locallyRunningTaskInstancesMap.put(task.getTaskIdentifier(), task);
            LOGGER.trace("Registered task {}, locally running instances = {}", task, locallyRunningTaskInstancesMap);
        }
    }

    public void unregisterRunningTask(TaskQuartzImpl task) {
        synchronized (locallyRunningTaskInstancesMap) {
            locallyRunningTaskInstancesMap.remove(task.getTaskIdentifier());
            LOGGER.trace("Unregistered task {}, locally running instances = {}", task, locallyRunningTaskInstancesMap);
        }
    }

    //endregion

    //region Transient and lightweight tasks
//    public void registerTransientSubtask(TaskQuartzImpl subtask, TaskQuartzImpl parent) {
//        Validate.notNull(subtask, "Subtask is null");
//        Validate.notNull(parent, "Parent task is null");
//        if (parent.isTransient()) {
//            registerTransientTask(parent);
//        }
//        registerTransientTask(subtask);
//    }
//
//    public void registerTransientTask(TaskQuartzImpl task) {
//        Validate.notNull(task, "Task is null");
//        Validate.notNull(task.getTaskIdentifier(), "Task identifier is null");
//        registeredTransientTasks.put(task.getTaskIdentifier(), task);
//    }

    public void startLightweightTask(final TaskQuartzImpl task) {
        if (task.isPersistent()) {
            throw new IllegalStateException("An attempt to start LightweightTaskHandler in a persistent task; task = " + task);
        }

        final LightweightTaskHandler lightweightTaskHandler = task.getLightweightTaskHandler();
        if (lightweightTaskHandler == null) {
            // nothing to do
            return;
        }

        synchronized(task) {
            if (task.lightweightHandlerStartRequested()) {
                throw new IllegalStateException("Handler for the lightweight task " + task + " has already been started.");
            }
            if (task.getExecutionStatus() != TaskExecutionStatus.RUNNABLE) {
                throw new IllegalStateException("Handler for lightweight task " + task + " couldn't be started because the task's state is " + task.getExecutionStatus());
            }

            Runnable r = () -> {
                LOGGER.debug("Lightweight task handler shell starting execution; task = {}", task);

                try {
	                // Setup Spring Security context
	                securityContextManager.setupPreAuthenticatedSecurityContext(task.getOwner());
                } catch (SchemaException e) {
                    LoggingUtils.logUnexpectedException(LOGGER, "Couldn't set up task security context {}", e, task);
                    throw new SystemException(e.getMessage(), e);
                }

                try {
                    task.setLightweightHandlerExecuting(true);
                    lightweightTaskHandler.run(task);
                } catch (Throwable t) {
                    LoggingUtils.logUnexpectedException(LOGGER, "Lightweight task handler has thrown an exception; task = {}", t, task);
                } finally {
                    task.setLightweightHandlerExecuting(false);
                }
                LOGGER.debug("Lightweight task handler shell finishing; task = {}", task);
                try {
                    // TODO what about concurrency here??!
                    closeTask(task, task.getResult());
                    // commented out, as currently LATs cannot participate in dependency relationships
                    //task.checkDependentTasksOnClose(task.getResult());
                    // task.updateStoredTaskResult();   // has perhaps no meaning for transient tasks
                } catch (Exception e) {     // todo
                    LoggingUtils.logUnexpectedException(LOGGER, "Couldn't correctly close task {}", e, task);
                }
            };

            Future future = lightweightHandlersExecutor.submit(r);
            task.setLightweightHandlerFuture(future);
            LOGGER.debug("Lightweight task handler submitted to start; task = {}", task);
        }
    }

    @Override
    public void waitForTransientChildren(Task task, OperationResult result) {
        for (Task subtask : task.getRunningLightweightAsynchronousSubtasks()) {
            Future future = ((TaskQuartzImpl) subtask).getLightweightHandlerFuture();
            if (future != null) {       // should always be
                LOGGER.debug("Waiting for subtask {} to complete.", subtask);
                try {
                    future.get();
                } catch (CancellationException e) {
                    // the Future was cancelled; however, the run() method may be still executing
                    // we want to be sure it is already done
                    while (((TaskQuartzImpl) subtask).isLightweightHandlerExecuting()) {
                        LOGGER.debug("Subtask {} was cancelled, waiting for its real completion.", subtask);
                        try {
                            Thread.sleep(500);
                        } catch (InterruptedException e1) {
                            LOGGER.warn("Waiting for subtask {} completion interrupted.", subtask);
                            break;
                        }
                    }
                } catch (Throwable t) {
                    LoggingUtils.logUnexpectedException(LOGGER, "Exception while waiting for subtask {} to complete.", t, subtask);
                    result.recordWarning("Got exception while waiting for subtask " + subtask + " to complete: " + t.getMessage(), t);
                }
                LOGGER.debug("Waiting for subtask {} done.", subtask);
            }
        }
    }

    //endregion

    //region Getting and searching for tasks and nodes
    /*
     *  ********************* GETTING AND SEARCHING FOR TASKS AND NODES *********************
     */

    @Override
    public <T extends ObjectType> PrismObject<T> getObject(Class<T> type,
                                                           String oid,
                                                           Collection<SelectorOptions<GetOperationOptions>> options,
                                                           OperationResult parentResult) throws SchemaException, ObjectNotFoundException {

        OperationResult result = parentResult.createMinorSubresult(DOT_INTERFACE + ".getObject");
        result.addParam("objectType", type);
        result.addParam("oid", oid);
        result.addArbitraryObjectCollectionAsParam("options", options);
        result.addContext(OperationResult.CONTEXT_IMPLEMENTATION_CLASS, TaskManagerQuartzImpl.class);

        try {
            if (TaskType.class.isAssignableFrom(type)) {
                GetOperationOptions rootOptions = SelectorOptions.findRootOptions(options);
                if (GetOperationOptions.isRaw(rootOptions)) {
	                //noinspection unchecked
	                return (PrismObject<T>) repositoryService.getObject(TaskType.class, oid, options, result);
                } else {
	                //noinspection unchecked
	                return (PrismObject<T>) getTaskAsObject(oid, options, result);
                }
            } else if (NodeType.class.isAssignableFrom(type)) {
	            //noinspection unchecked
	            return (PrismObject<T>) repositoryService.getObject(NodeType.class, oid, options, result);      // TODO add transient attributes just like in searchObject
            } else {
                throw new IllegalArgumentException("Unsupported object type: " + type);
            }
        } finally {
            result.computeStatusIfUnknown();
        }
    }

    private PrismObject<TaskType> getTaskAsObject(String oid, Collection<SelectorOptions<GetOperationOptions>> options, OperationResult result) throws SchemaException, ObjectNotFoundException {

        ClusterStatusInformation clusterStatusInformation = getClusterStatusInformation(options, TaskType.class, true, result); // returns null if noFetch is set

        Task task = getTask(oid, result);
        addTransientTaskInformation(task.getTaskPrismObject(),
                clusterStatusInformation,
                SelectorOptions.hasToLoadPath(new ItemPath(TaskType.F_NEXT_RUN_START_TIMESTAMP), options),
                SelectorOptions.hasToLoadPath(new ItemPath(TaskType.F_NEXT_RETRY_TIMESTAMP), options),
                SelectorOptions.hasToLoadPath(new ItemPath(TaskType.F_NODE_AS_OBSERVED), options),
                result);

        if (SelectorOptions.hasToLoadPath(TaskType.F_SUBTASK, options)) {
            fillInSubtasks(task, clusterStatusInformation, options, result);
        }
        fillOperationExecutionState(task);
        return task.getTaskPrismObject();
    }

    private void fillOperationExecutionState(Task task0) {
        TaskQuartzImpl task = (TaskQuartzImpl) task0;

        if (task.getTaskIdentifier() == null) {
            return;     // shouldn't really occur
        }

        Task taskInMemory = getLocallyRunningTaskByIdentifier(task.getTaskIdentifier());
        if (taskInMemory == null) {
            return;
        }

        OperationStatsType operationStats = taskInMemory.getAggregatedLiveOperationStats();
        if (operationStats != null) {
            operationStats.setLiveInformation(true);
        }
        task.setOperationStatsTransient(operationStats);
        task.setProgressTransient(taskInMemory.getProgress());

        OperationResult result = taskInMemory.getResult();
        if (result != null) {
        	try {
		        task.setResultTransient(taskInMemory.getResult().clone());
	        } catch (ConcurrentModificationException e) {
        		// This can occur, see MID-3954/MID-4088. We will use operation result that was fetched from the repository
		        // (it might be a bit outdated).
		        LOGGER.warn("Concurrent access to operation result denied; using data from the repository (see MID-3954/MID-4088): {}", task, e);
	        }
        } else {
            task.setResultTransient(null);
        }
    }

	// TODO deduplicate
	private void fillInSubtasks(Task task, ClusterStatusInformation clusterStatusInformation, Collection<SelectorOptions<GetOperationOptions>> options, OperationResult result) throws SchemaException {
		boolean retrieveNextRunStartTime = SelectorOptions.hasToLoadPath(new ItemPath(TaskType.F_NEXT_RUN_START_TIMESTAMP), options);
		boolean retrieveRetryTime = SelectorOptions.hasToLoadPath(new ItemPath(TaskType.F_NEXT_RETRY_TIMESTAMP), options);
		boolean retrieveNodeAsObserved = SelectorOptions.hasToLoadPath(new ItemPath(TaskType.F_NODE_AS_OBSERVED), options);

		List<Task> subtasks = task.listSubtasks(result);

		for (Task subtask : subtasks) {

			if (subtask.isPersistent()) {
				addTransientTaskInformation(subtask.getTaskPrismObject(),
						clusterStatusInformation,
						retrieveNextRunStartTime,
						retrieveRetryTime,
						retrieveNodeAsObserved,
						result);

				fillInSubtasks(subtask, clusterStatusInformation, options, result);
			}
			TaskType subTaskType = subtask.getTaskPrismObject().asObjectable();
			task.getTaskPrismObject().asObjectable().getSubtask().add(subTaskType);
		}
	}

	// retrieves only "heavyweight" subtasks
    private void fillInSubtasks(TaskType task, ClusterStatusInformation clusterStatusInformation, Collection<SelectorOptions<GetOperationOptions>> options, OperationResult result) throws SchemaException {

	    boolean retrieveNextRunStartTime = SelectorOptions.hasToLoadPath(new ItemPath(TaskType.F_NEXT_RUN_START_TIMESTAMP), options);
        boolean retrieveRetryTime = SelectorOptions.hasToLoadPath(new ItemPath(TaskType.F_NEXT_RETRY_TIMESTAMP), options);
        boolean retrieveNodeAsObserved = SelectorOptions.hasToLoadPath(new ItemPath(TaskType.F_NODE_AS_OBSERVED), options);

        List<PrismObject<TaskType>> subtasks = listSubtasksForTask(task.getTaskIdentifier(), result);

        for (PrismObject<TaskType> subtask : subtasks) {

            if (subtask.getOid() != null) {
                addTransientTaskInformation(subtask,
                        clusterStatusInformation,
                        retrieveNextRunStartTime,
						retrieveRetryTime,
                        retrieveNodeAsObserved,
                        result);

                fillInSubtasks(subtask.asObjectable(), clusterStatusInformation, options, result);
            }
            task.getSubtask().add(subtask.asObjectable());
        }
    }

	public List<PrismObject<TaskType>> listSubtasksForTask(String taskIdentifier, OperationResult result) throws SchemaException {

		if (StringUtils.isEmpty(taskIdentifier)) {
			return new ArrayList<>();
		}
		ObjectQuery query = QueryBuilder.queryFor(TaskType.class, prismContext)
				.item(TaskType.F_PARENT).eq(taskIdentifier)
				.build();

		List<PrismObject<TaskType>> list;
		try {
			list = repositoryService.searchObjects(TaskType.class, query, null, result);
			result.recordSuccessIfUnknown();
		} catch (SchemaException | RuntimeException e) {
			result.recordFatalError(e);
			throw e;
		}
		return list;
	}

	@Override
    public <T extends ObjectType> SearchResultList<PrismObject<T>> searchObjects(Class<T> type,
                                                                     ObjectQuery query,
                                                                     Collection<SelectorOptions<GetOperationOptions>> options,
                                                                     OperationResult parentResult) throws SchemaException {

        OperationResult result = parentResult.createMinorSubresult(DOT_INTERFACE + ".searchObjects");
        result.addParam("objectType", type);
        result.addParam("query", query);
        result.addArbitraryObjectCollectionAsParam("options", options);
        result.addContext(OperationResult.CONTEXT_IMPLEMENTATION_CLASS, TaskManagerQuartzImpl.class);

        if (TaskType.class.isAssignableFrom(type)) {
	        //noinspection unchecked
	        return (SearchResultList<PrismObject<T>>) (SearchResultList) searchTasks(query, options, result);
        } else if (NodeType.class.isAssignableFrom(type)) {
	        //noinspection unchecked
	        return (SearchResultList<PrismObject<T>>) (SearchResultList) searchNodes(query, options, result);
        } else {
            throw new IllegalArgumentException("Unsupported object type: " + type);
        }
    }

	@Override
	public <T extends ObjectType> SearchResultMetadata searchObjectsIterative(Class<T> type,
			ObjectQuery query, Collection<SelectorOptions<GetOperationOptions>> options,
			ResultHandler<T> handler, OperationResult parentResult) throws SchemaException {
		OperationResult result = parentResult.createMinorSubresult(DOT_INTERFACE + ".searchObjects");
        result.addParam("objectType", type);
        result.addParam("query", query);
        result.addArbitraryObjectCollectionAsParam("options", options);
        result.addContext(OperationResult.CONTEXT_IMPLEMENTATION_CLASS, TaskManagerQuartzImpl.class);

        SearchResultList<PrismObject<T>> objects;
        if (TaskType.class.isAssignableFrom(type)) {
	        //noinspection unchecked
	        objects = (SearchResultList<PrismObject<T>>) (SearchResultList) searchTasks(query, options, result);
        } else if (NodeType.class.isAssignableFrom(type)) {
	        //noinspection unchecked
	        objects = (SearchResultList<PrismObject<T>>) (SearchResultList) searchNodes(query, options, result);
        } else {
            throw new IllegalArgumentException("Unsupported object type: " + type);
        }

        for (PrismObject<T> object: objects) {
        	handler.handle(object, result);
        }

        result.computeStatus();
        return objects.getMetadata();
	}

    @Override
    public <T extends ObjectType> int countObjects(Class<T> type,
                                                   ObjectQuery query,
                                                   OperationResult parentResult) throws SchemaException {

        OperationResult result = parentResult.createMinorSubresult(DOT_INTERFACE + ".countObjects");
        result.addParam("objectType", type);
        result.addParam("query", query);
        result.addContext(OperationResult.CONTEXT_IMPLEMENTATION_CLASS, TaskManagerQuartzImpl.class);

        try {
            return repositoryService.countObjects(type, query, null, parentResult);
        } finally {
            result.computeStatus();
        }
    }



    /*
     * Gets nodes from repository and adds runtime information to them (taken from ClusterStatusInformation).
     */
//    @Override
//    public int countNodes(ObjectQuery query, OperationResult result) throws SchemaException {
//        return repositoryService.countObjects(NodeType.class, query, result);
//    }

    private SearchResultList<PrismObject<NodeType>> searchNodes(ObjectQuery query, Collection<SelectorOptions<GetOperationOptions>> options, OperationResult result) throws SchemaException {

        ClusterStatusInformation clusterStatusInformation = getClusterStatusInformation(options, NodeType.class, true, result);

        List<PrismObject<NodeType>> nodesInRepository;
        try {
            nodesInRepository = repositoryService.searchObjects(NodeType.class, query, options, result);
        } catch (SchemaException e) {
            result.recordFatalError("Couldn't get nodes from repository: " + e.getMessage());
            throw e;
        }

        List<PrismObject<NodeType>> list = new ArrayList<>();

        if (clusterStatusInformation != null) {
            for (PrismObject<NodeType> nodeInRepositoryPrism : nodesInRepository) {
                NodeType returnedNode = nodeInRepositoryPrism.asObjectable();

                NodeType nodeRuntimeInfo = clusterStatusInformation.findNodeById(returnedNode.getNodeIdentifier());
                if (nodeRuntimeInfo != null) {
                    returnedNode.setExecutionStatus(nodeRuntimeInfo.getExecutionStatus());
                    returnedNode.setErrorStatus(nodeRuntimeInfo.getErrorStatus());
                    returnedNode.setConnectionResult(nodeRuntimeInfo.getConnectionResult());
                } else {
                    // node is in repo, but no information on it is present in CSI
                    // (should not occur except for some temporary conditions, because CSI contains info on all nodes from repo)
                    returnedNode.setExecutionStatus(NodeExecutionStatusType.COMMUNICATION_ERROR);
                    OperationResult r = new OperationResult("connect");
                    r.recordFatalError("Node not known at this moment");
                    returnedNode.setConnectionResult(r.createOperationResultType());
                }
                list.add(returnedNode.asPrismObject());
            }
        } else {
            list = nodesInRepository;
        }
        LOGGER.trace("searchNodes returning {}", list);
        result.computeStatus();
        return new SearchResultList<>(list);
    }

    private ClusterStatusInformation getClusterStatusInformation(Collection<SelectorOptions<GetOperationOptions>> options, Class<? extends ObjectType> objectClass, boolean allowCached, OperationResult result) {
        boolean noFetch = GetOperationOptions.isNoFetch(SelectorOptions.findRootOptions(options));
        boolean retrieveStatus;

        if (noFetch) {
            retrieveStatus = false;
        } else {
            if (objectClass.equals(TaskType.class)) {
                retrieveStatus = SelectorOptions.hasToLoadPath(new ItemPath(TaskType.F_NODE_AS_OBSERVED), options);
            } else if (objectClass.equals(NodeType.class)) {
                retrieveStatus = true;                          // implement some determination algorithm if needed
            } else {
                throw new IllegalArgumentException("object class: " + objectClass);
            }
        }

        if (retrieveStatus) {
            return executionManager.getClusterStatusInformation(true, allowCached, result);
        } else {
            return null;
        }
    }

    public SearchResultList<PrismObject<TaskType>> searchTasks(ObjectQuery query, Collection<SelectorOptions<GetOperationOptions>> options, OperationResult result) throws SchemaException {

        ClusterStatusInformation clusterStatusInformation = getClusterStatusInformation(options, TaskType.class, true, result); // returns null if noFetch is set

        List<PrismObject<TaskType>> tasksInRepository;
        try {
            tasksInRepository = repositoryService.searchObjects(TaskType.class, query, options, result);
        } catch (SchemaException e) {
            result.recordFatalError("Couldn't get tasks from repository: " + e.getMessage(), e);
            throw e;
        }

        boolean retrieveNextRunStartTime = SelectorOptions.hasToLoadPath(new ItemPath(TaskType.F_NEXT_RUN_START_TIMESTAMP), options);
        boolean retrieveRetryTime = SelectorOptions.hasToLoadPath(new ItemPath(TaskType.F_NEXT_RETRY_TIMESTAMP), options);
        boolean retrieveNodeAsObserved = SelectorOptions.hasToLoadPath(new ItemPath(TaskType.F_NODE_AS_OBSERVED), options);

        List<PrismObject<TaskType>> retval = new ArrayList<>();
        for (PrismObject<TaskType> taskInRepository : tasksInRepository) {
            TaskType taskInResult = addTransientTaskInformation(taskInRepository, clusterStatusInformation,
					retrieveNextRunStartTime, retrieveRetryTime, retrieveNodeAsObserved, result);
            retval.add(taskInResult.asPrismObject());
        }
        result.computeStatus();
        return new SearchResultList<>(retval);
    }

    private TaskType addTransientTaskInformation(PrismObject<TaskType> taskInRepository, ClusterStatusInformation clusterStatusInformation,
			boolean retrieveNextRunStartTime, boolean retrieveRetryTime, boolean retrieveNodeAsObserved, OperationResult result) {

        Validate.notNull(taskInRepository.getOid(), "Task OID is null");
        TaskType taskInResult = taskInRepository.asObjectable();
        if (clusterStatusInformation != null && retrieveNodeAsObserved) {
            NodeType runsAt = clusterStatusInformation.findNodeInfoForTask(taskInResult.getOid());
            if (runsAt != null) {
                taskInResult.setNodeAsObserved(runsAt.getNodeIdentifier());
            }
        }
        if (retrieveNextRunStartTime || retrieveRetryTime) {
            NextStartTimes times = getNextStartTimes(taskInResult.getOid(), retrieveNextRunStartTime, retrieveRetryTime, result);
            if (retrieveNextRunStartTime && times.nextScheduledRun != null) {
                taskInResult.setNextRunStartTimestamp(XmlTypeConverter.createXMLGregorianCalendar(times.nextScheduledRun));
            }
            if (retrieveRetryTime && times.nextRetry != null) {
                taskInResult.setNextRetryTimestamp(XmlTypeConverter.createXMLGregorianCalendar(times.nextRetry));
            }
        }
        Long stalledSince = stalledTasksWatcher.getStalledSinceForTask(taskInResult);
        if (stalledSince != null) {
            taskInResult.setStalledSince(XmlTypeConverter.createXMLGregorianCalendar(stalledSince));
        }
        return taskInResult;
    }


//    @Override
//    public int countTasks(ObjectQuery query, OperationResult result) throws SchemaException {
//        return repositoryService.countObjects(TaskType.class, query, result);
//    }
    //endregion

	//region Deletion listeners

	@Override
	public void registerTaskDeletionListener(TaskDeletionListener listener) {
		Validate.notNull(listener, "Task deletion listener is null");
		taskDeletionListeners.add(listener);
	}

	//endregion

    //region Managing handlers and task categories
    /*
    *  ********************* MANAGING HANDLERS AND TASK CATEGORIES *********************
    */

	@Override
	public void registerHandler(String uri, TaskHandler handler) {
        LOGGER.trace("Registering task handler for URI {}", uri);
		handlers.put(uri, handler);
	}

	public TaskHandler getHandler(String uri) {
		if (uri != null)
			return handlers.get(uri);
		else
			return null;
	}

    @Override
    public List<String> getAllTaskCategories() {

        Set<String> categories = new HashSet<>();
        for (TaskHandler h : handlers.values()) {
            List<String> cat = h.getCategoryNames();
            if (cat != null) {
                categories.addAll(cat);
            } else {
                String catName = h.getCategoryName(null);
                if (catName != null) {
                    categories.add(catName);
                }
            }
        }
        return new ArrayList<>(categories);
    }

    @Override
    public String getHandlerUriForCategory(String category) {
        for (Map.Entry<String,TaskHandler> h : handlers.entrySet()) {
            List<String> cats = h.getValue().getCategoryNames();
            if (cats != null) {
				if (cats.contains(category)) {
					return h.getKey();
				}
            } else {
                String cat = h.getValue().getCategoryName(null);
                if (category.equals(cat)) {
                    return h.getKey();
                }
            }
        }
        return null;
    }
    //endregion

    //region Task creation/removal listeners
    /*
    *  ********************* TASK CREATION/REMOVAL LISTENERS *********************
    */

    @Override
    public void onTaskCreate(String oid, OperationResult parentResult) {

        OperationResult result = parentResult.createMinorSubresult(DOT_INTERFACE + "onTaskCreate");
        result.addParam("oid", oid);

        LOGGER.trace("onTaskCreate called for oid = " + oid);

        TaskQuartzImpl task;
        try {
            task = getTask(oid, result);
        } catch (ObjectNotFoundException e) {
            LoggingUtils.logException(LOGGER, "Quartz shadow job cannot be created, because task in repository was not found; oid = {}", e, oid);
            result.computeStatus();
            return;
        } catch (SchemaException e) {
            LoggingUtils.logUnexpectedException(LOGGER, "Quartz shadow job cannot be created, because task from repository could not be retrieved; oid = {}", e, oid);
            result.computeStatus();
            return;
        }

        task.synchronizeWithQuartz(result);
        result.computeStatus();
    }

    @Override
    public void onTaskDelete(String oid, OperationResult parentResult) {

        OperationResult result = parentResult.createMinorSubresult(DOT_INTERFACE + "onTaskDelete");
        result.addParam("oid", oid);

        LOGGER.trace("onTaskDelete called for oid = " + oid);

        JobKey jobKey = TaskQuartzImplUtil.createJobKeyForTaskOid(oid);

        try {
            if (executionManager.getQuartzScheduler().checkExists(jobKey)) {
                executionManager.getQuartzScheduler().deleteJob(jobKey);			// removes triggers as well
            }
        } catch (SchedulerException e) {
            String message = "Quartz shadow job cannot be removed; oid = " + oid;
            LoggingUtils.logUnexpectedException(LOGGER, message, e);
            result.recordFatalError(message);
        }

        result.recordSuccessIfUnknown();

    }
    //endregion

    //region Notifications
    @Override
    public void registerTaskListener(TaskListener taskListener) {
        taskListeners.add(taskListener);
    }

    @Override
    public void unregisterTaskListener(TaskListener taskListener) {
        taskListeners.remove(taskListener);
    }

    public void notifyTaskStart(Task task) {
        for (TaskListener taskListener : taskListeners) {
            try {
                taskListener.onTaskStart(task);
            } catch (RuntimeException e) {
                logListenerException(e);
            }
        }
    }

    private void logListenerException(RuntimeException e) {
        LoggingUtils.logUnexpectedException(LOGGER, "Task listener returned an unexpected exception", e);
    }

    public void notifyTaskFinish(Task task, TaskRunResult runResult) {
        for (TaskListener taskListener : taskListeners) {
            try {
                taskListener.onTaskFinish(task, runResult);
            } catch (RuntimeException e) {
                logListenerException(e);
            }
        }
    }

    public void notifyTaskThreadStart(Task task, boolean isRecovering) {
        for (TaskListener taskListener : taskListeners) {
            try {
                taskListener.onTaskThreadStart(task, isRecovering);
            } catch (RuntimeException e) {
                logListenerException(e);
            }
        }
    }

    public void notifyTaskThreadFinish(Task task) {
        for (TaskListener taskListener : taskListeners) {
            try {
                taskListener.onTaskThreadFinish(task);
            } catch (RuntimeException e) {
                logListenerException(e);
            }
        }
    }

    //endregion

    //region Other methods + getters and setters (CLEAN THIS UP)
    /*
     *  ********************* OTHER METHODS + GETTERS AND SETTERS *********************
     */

    PrismObjectDefinition<TaskType> getTaskObjectDefinition() {
		if (taskPrismDefinition == null) {
			taskPrismDefinition = prismContext.getSchemaRegistry().findObjectDefinitionByCompileTimeClass(TaskType.class);
		}
		return taskPrismDefinition;
	}

    private OperationResult createOperationResult(String methodName) {
        return new OperationResult(TaskManagerQuartzImpl.class.getName() + "." + methodName);
    }

    public TaskManagerConfiguration getConfiguration() {
        return configuration;
    }

    public PrismContext getPrismContext() {
        return prismContext;
    }

    public NodeErrorStatusType getLocalNodeErrorStatus() {
        return nodeErrorStatus;
    }

    public void setNodeErrorStatus(NodeErrorStatusType nodeErrorStatus) {
        this.nodeErrorStatus = nodeErrorStatus;
    }

    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        this.beanFactory = beanFactory;
    }

    public MidpointConfiguration getMidpointConfiguration() {
        return midpointConfiguration;
    }

    public BeanFactory getBeanFactory() {
        return beanFactory;
    }

    public ClusterManager getClusterManager() {
        return clusterManager;
    }

    public RepositoryService getRepositoryService() {
        return repositoryService;
    }

    public ExecutionManager getExecutionManager() {
        return executionManager;
    }

    //endregion

    //region Delegation (CLEAN THIS UP)
    /*
     *  ********************* DELEGATIONS *********************
     */

	void synchronizeTaskWithQuartz(TaskQuartzImpl task, OperationResult parentResult) {
        executionManager.synchronizeTask(task, parentResult);
    }

    @Override
    public void synchronizeTasks(OperationResult result) {
        executionManager.synchronizeJobStores(result);
    }

    @Override
    public String getNodeId() {
        return configuration.getNodeId();
    }

    @Override
    public Set<Task> getLocallyRunningTasks(OperationResult parentResult) {
        return executionManager.getLocallyRunningTasks(parentResult);
    }

    @Override
    public Task getLocallyRunningTaskByIdentifier(String lightweightIdentifier) {
        synchronized (locallyRunningTaskInstancesMap) {
            return locallyRunningTaskInstancesMap.get(lightweightIdentifier);
        }
    }

    @Override
    public void stopScheduler(String nodeIdentifier, OperationResult parentResult) {
        executionManager.stopScheduler(nodeIdentifier, parentResult);
    }

    @Override
    public void stopSchedulers(Collection<String> nodeIdentifiers, OperationResult parentResult) {
        OperationResult result = new OperationResult(DOT_INTERFACE + "stopSchedulers");
        for (String nodeIdentifier : nodeIdentifiers) {
            stopScheduler(nodeIdentifier, result);
        }
        result.computeStatus();
    }

    @Override
    public void startScheduler(String nodeIdentifier, OperationResult parentResult) {
        executionManager.startScheduler(nodeIdentifier, parentResult);
    }

    @Override
    public void startSchedulers(Collection<String> nodeIdentifiers, OperationResult parentResult) {
        OperationResult result = new OperationResult(DOT_INTERFACE + "startSchedulers");
        for (String nodeIdentifier : nodeIdentifiers) {
            startScheduler(nodeIdentifier, result);
        }
        result.computeStatus();
    }

    @Override
    public boolean stopSchedulersAndTasks(Collection<String> nodeIdentifiers, long timeToWait, OperationResult result) {
        return executionManager.stopSchedulersAndTasks(nodeIdentifiers, timeToWait, result);
    }

    @Override
    public boolean isCurrentNode(PrismObject<NodeType> node) {
        return clusterManager.isCurrentNode(node);
    }

    @Override
    public void deleteNode(String nodeOid, OperationResult result) throws SchemaException, ObjectNotFoundException {
        clusterManager.deleteNode(nodeOid, result);
    }

    @Override
    public void scheduleTaskNow(Task task, OperationResult parentResult) throws SchemaException, ObjectNotFoundException {
        /*
         *  Note: we clear task operation result because this is what a user would generally expect when re-running a task
         *  (MID-1920). We do NOT do that on each task run e.g. to have an ability to see last task execution status
         *  during a next task run. (When the interval between task runs is too short, e.g. for live sync tasks.)
         */
        if (task.isClosed()) {
            clearTaskOperationResult(task, parentResult);
            executionManager.reRunClosedTask(task, parentResult);
        } else if (task.getExecutionStatus() == TaskExecutionStatus.RUNNABLE) {
            clearTaskOperationResult(task, parentResult);
            scheduleRunnableTaskNow(task, parentResult);
        } else if (task.getExecutionStatus() == TaskExecutionStatus.WAITING) {
	        clearTaskOperationResult(task, parentResult);
	        scheduleWaitingTaskNow(task, parentResult);
        } else {
            String message = "Task " + task + " cannot be run now, because it is not in RUNNABLE nor CLOSED state. State is " + task.getExecutionStatus();
            parentResult.createSubresult(DOT_INTERFACE + "scheduleTaskNow").recordFatalError(message);
            LOGGER.error(message);
		}
    }

    private void clearTaskOperationResult(Task task, OperationResult parentResult) throws SchemaException, ObjectNotFoundException {
        OperationResult emptyTaskResult = new OperationResult("run");
        emptyTaskResult.setStatus(OperationResultStatus.IN_PROGRESS);
        task.setResultImmediate(emptyTaskResult, parentResult);
    }

    public void scheduleRunnableTaskNow(Task task, OperationResult parentResult) {
        executionManager.scheduleRunnableTaskNow(task, parentResult);
    }

    public void scheduleWaitingTaskNow(Task task, OperationResult parentResult) {
        executionManager.scheduleWaitingTaskNow(task, parentResult);
    }

    @Override
    public void scheduleTasksNow(Collection<String> taskOids, OperationResult parentResult) {
        OperationResult result = parentResult.createSubresult(DOT_INTERFACE + "scheduleTasksNow");
        result.addArbitraryObjectCollectionAsParam("taskOids", taskOids);
        for (String oid : taskOids) {
            try {
                scheduleTaskNow(getTask(oid, result), result);
            } catch (ObjectNotFoundException e) {
                LoggingUtils.logException(LOGGER, "Couldn't schedule task with OID {}", e, oid);
            } catch (SchemaException e) {
                LoggingUtils.logUnexpectedException(LOGGER, "Couldn't schedule task with OID {}", e, oid);
            }
        }
        result.computeStatus();
    }

    public void unscheduleTask(Task task, OperationResult parentResult) {
        executionManager.unscheduleTask(task, parentResult);
    }

    // use with care (e.g. w.r.t. dependent tasks)
    public void closeTask(Task task, OperationResult parentResult) throws ObjectNotFoundException, SchemaException {
        try {
			OperationResult taskResult = updateTaskResult(task);
			task.close(taskResult, true, parentResult);
        } finally {
            if (task.isPersistent()) {
                executionManager.removeTaskFromQuartz(task.getOid(), parentResult);
            }
        }
    }

	private boolean shouldPurgeResult(Task task) {
		return PURGE_SUCCESSFUL_RESULT_FOR.contains(task.getCategory()) &&
				task.getResultStatus() == OperationResultStatusType.SUCCESS || task.getResultStatus() == OperationResultStatusType.IN_PROGRESS;
	}

	// do not forget to kick dependent tasks when closing this one (currently only done in finishHandler)
    public void closeTaskWithoutSavingState(Task task, OperationResult parentResult) {
		OperationResult taskResult = updateTaskResult(task);
		try {
			task.close(taskResult, false, parentResult);
		} catch (ObjectNotFoundException | SchemaException e) {
			throw new SystemException(e);       // shouldn't occur
		}
        executionManager.removeTaskFromQuartz(task.getOid(), parentResult);
    }

    // returns null if no change is needed in the task
	@Nullable
	private OperationResult updateTaskResult(Task task) {
		OperationResult taskResult = task.getResult();
		if (taskResult == null) {
			// should not occur
			return null;
		}
		boolean resultChanged = false;
		// this is a bit of magic to ensure closed tasks will not stay with IN_PROGRESS result (and, if possible, also not with UNKNOWN)
		if (taskResult.getStatus() == IN_PROGRESS || taskResult.getStatus() == UNKNOWN) {
			taskResult.computeStatus();
			if (taskResult.getStatus() == IN_PROGRESS) {
				taskResult.setStatus(SUCCESS);
			}
			resultChanged = true;
		}
		if (shouldPurgeResult(task)) {
			taskResult = OperationResult.keepRootOnly(taskResult);
			resultChanged = true;
		}
		return resultChanged ? taskResult : null;
	}

	@Override
    public ParseException validateCronExpression(String cron) {
        return TaskQuartzImplUtil.validateCronExpression(cron);
    }

    // currently finds only persistent tasks
    @Override
    @NotNull
    public Task getTaskByIdentifier(String identifier, OperationResult parentResult) throws SchemaException, ObjectNotFoundException {

        OperationResult result = parentResult.createMinorSubresult(DOT_INTERFACE + "getTaskByIdentifier");
        result.addParam("identifier", identifier);
        result.addContext(OperationResult.CONTEXT_IMPLEMENTATION_CLASS, TaskManagerQuartzImpl.class);

        Task task = createTaskInstance(getTaskTypeByIdentifier(identifier, null, result), result);
        result.computeStatus();
        return task;
    }

    @Override
    @NotNull
    public PrismObject<TaskType> getTaskTypeByIdentifier(String identifier, Collection<SelectorOptions<GetOperationOptions>> options, OperationResult parentResult) throws SchemaException, ObjectNotFoundException {
        OperationResult result = parentResult.createMinorSubresult(DOT_IMPL_CLASS + "getTaskTypeByIdentifier");
        result.addParam("identifier", identifier);
        result.addContext(OperationResult.CONTEXT_IMPLEMENTATION_CLASS, TaskManagerQuartzImpl.class);

		ObjectQuery query = QueryBuilder.queryFor(TaskType.class, prismContext)
				.item(TaskType.F_TASK_IDENTIFIER).eq(identifier)
				.build();

		List<PrismObject<TaskType>> list = repositoryService.searchObjects(TaskType.class, query, options, result);
		if (list.isEmpty()) {
			throw new ObjectNotFoundException("Task with identifier " + identifier + " could not be found");
		} else if (list.size() > 1) {
			throw new IllegalStateException("Found more than one task with identifier " + identifier + " (" + list.size() + " of them)");
		}
		PrismObject<TaskType> retval = list.get(0);
		if (SelectorOptions.hasToLoadPath(TaskType.F_SUBTASK, options)) {
			ClusterStatusInformation clusterStatusInformation = getClusterStatusInformation(options, TaskType.class, true, result); // returns null if noFetch is set
			fillInSubtasks(retval.asObjectable(), clusterStatusInformation, options, result);
		}
        result.computeStatusIfUnknown();
        return retval;
    }

    List<Task> resolveTasksFromTaskTypes(List<PrismObject<TaskType>> taskPrisms, OperationResult result) throws SchemaException {
        List<Task> tasks = new ArrayList<>(taskPrisms.size());
        for (PrismObject<TaskType> taskPrism : taskPrisms) {
            tasks.add(createTaskInstance(taskPrism, result));
        }

        result.recordSuccessIfUnknown();
        return tasks;
    }

    @Override
    public void cleanupTasks(CleanupPolicyType policy, Task executionTask, OperationResult parentResult) throws SchemaException {
        OperationResult result = parentResult.createSubresult(CLEANUP_TASKS);

        if (policy.getMaxAge() == null) {
            return;
        }

        Duration duration = policy.getMaxAge();
        if (duration.getSign() > 0) {
            duration = duration.negate();
        }
        Date deleteTasksClosedUpTo = new Date();
        duration.addTo(deleteTasksClosedUpTo);

        LOGGER.info("Starting cleanup for closed tasks deleting up to {} (duration '{}').", deleteTasksClosedUpTo, duration);

        XMLGregorianCalendar timeXml = XmlTypeConverter.createXMLGregorianCalendar(deleteTasksClosedUpTo.getTime());

        List<PrismObject<TaskType>> obsoleteTasks;
        try {
            ObjectQuery obsoleteTasksQuery = QueryBuilder.queryFor(TaskType.class, prismContext)
					.item(TaskType.F_COMPLETION_TIMESTAMP).le(timeXml)
					.and().item(TaskType.F_PARENT).isNull()
					.build();
            obsoleteTasks = repositoryService.searchObjects(TaskType.class, obsoleteTasksQuery, null, result);
        } catch (SchemaException e) {
            throw new SchemaException("Couldn't get the list of obsolete tasks: " + e.getMessage(), e);
        }

        // enable when having enough time
//        result.createSubresult(result.getOperation()+".count").recordStatus(SUCCESS, "Task tree(s) to be deleted: " + obsoleteTasks.size());
//        // show the result immediately
//        try {
//            executionTask.setResultImmediate(executionTask.getResult(), new OperationResult("dummy"));
//        } catch (ObjectNotFoundException e) {
//            LoggingUtils.logUnexpectedException(LOGGER, "Task {} does not exist", e, executionTask);
//        }

        LOGGER.debug("Found {} task tree(s) to be cleaned up", obsoleteTasks.size());

        boolean interrupted = false;
        int deleted = 0;
        int problems = 0;
        int bigProblems = 0;
        for (PrismObject<TaskType> rootTaskPrism : obsoleteTasks) {

            if (!executionTask.canRun()) {
                result.recordWarning("Interrupted");
                LOGGER.warn("Task cleanup was interrupted.");
                interrupted = true;
                break;
            }

            final String taskName = PolyString.getOrig(rootTaskPrism.getName());
            final String taskOid = rootTaskPrism.getOid();
            final long started = System.currentTimeMillis();
            executionTask.recordIterativeOperationStart(taskName, null, TaskType.COMPLEX_TYPE, taskOid);
            try {
                // get whole tree
                Task rootTask = createTaskInstance(rootTaskPrism, result);
                List<Task> taskTreeMembers = rootTask.listSubtasksDeeply(result);
                taskTreeMembers.add(rootTask);

                LOGGER.trace("Removing task {} along with its {} children.", rootTask, taskTreeMembers.size() - 1);

                Throwable lastProblem = null;
                for (Task task : taskTreeMembers) {
                    try {
                        deleteTask(task.getOid(), result);
                        deleted++;
                    } catch (SchemaException|ObjectNotFoundException|RuntimeException e) {
                        LoggingUtils.logUnexpectedException(LOGGER, "Couldn't delete obsolete task {}", e, task);
                        lastProblem = e;
                        problems++;
                        if (!task.getTaskIdentifier().equals(rootTask.getTaskIdentifier())) {
                            bigProblems++;
                        }
                    }
                }
                // approximate solution (as the problem might be connected to a subtask)
                executionTask.recordIterativeOperationEnd(taskName, null, TaskType.COMPLEX_TYPE, taskOid, started, lastProblem);
            } catch (Throwable t) {
                executionTask.recordIterativeOperationEnd(taskName, null, TaskType.COMPLEX_TYPE, taskOid, started, t);
                throw t;
            }
	        executionTask.incrementProgressAndStoreStatsIfNeeded();
        }
        result.computeStatusIfUnknown();

        LOGGER.info("Task cleanup procedure " + (interrupted ? "was interrupted" : "finished") + ". Successfully deleted {} tasks; there were problems with deleting {} tasks.", deleted, problems);
        if (bigProblems > 0) {
            LOGGER.error("{} subtask(s) couldn't be deleted. Inspect that manually, otherwise they might reside in repo forever.", bigProblems);
        }
        String suffix = interrupted ? " Interrupted." : "";
        if (problems == 0) {
            parentResult.createSubresult(CLEANUP_TASKS + ".statistics").recordStatus(SUCCESS, "Successfully deleted " + deleted + " task(s)." + suffix);
        } else {
            parentResult.createSubresult(CLEANUP_TASKS + ".statistics").recordPartialError("Successfully deleted " + deleted + " task(s), "
                    + "there was problems with deleting " + problems + " tasks." + suffix
                    + (bigProblems > 0 ? (" " + bigProblems + " subtask(s) couldn't be deleted, please see the log.") : ""));
        }

    }

	// if there are problems with retrieving a task, we just log exception and put into operation result
    private List<Task> resolveTaskOids(Collection<String> oids, OperationResult parentResult) {
        List<Task> retval = new ArrayList<>();
        OperationResult result = parentResult.createMinorSubresult(DOT_IMPL_CLASS + ".resolveTaskOids");
        for (String oid : oids) {
            try {
                retval.add(getTask(oid, result));
            } catch (ObjectNotFoundException e) {
                LoggingUtils.logException(LOGGER, "Couldn't retrieve task with OID {}", e, oid);        // result is updated in getTask
            } catch (SchemaException e) {
                LoggingUtils.logUnexpectedException(LOGGER, "Couldn't retrieve task with OID {}", e, oid);
            }
        }
        result.computeStatus();
        return retval;
    }

    @Override
    public Long getNextRunStartTime(String oid, OperationResult parentResult) {
        return getNextStartTimes(oid, true, false, parentResult).nextScheduledRun;
    }

    public static class NextStartTimes {
    	final Long nextScheduledRun;
    	final Long nextRetry;
		public NextStartTimes(Trigger standardTrigger, Trigger nextRetryTrigger) {
			this.nextScheduledRun = getTime(standardTrigger);
			this.nextRetry = getTime(nextRetryTrigger);
		}
		private Long getTime(Trigger t) {
			return t != null && t.getNextFireTime() != null ? t.getNextFireTime().getTime() : null;
		}
	}

	@NotNull
    public NextStartTimes getNextStartTimes(String oid, boolean retrieveNextRunStartTime, boolean retrieveRetryTime,
			OperationResult parentResult) {
        OperationResult result = parentResult.createMinorSubresult(DOT_INTERFACE + "getNextStartTimes");
        result.addParam("oid", oid);
        result.addParam("retrieveNextRunStartTime", retrieveNextRunStartTime);
        result.addParam("retrieveRetryTime", retrieveRetryTime);
        return executionManager.getNextStartTimes(oid, retrieveNextRunStartTime, retrieveRetryTime, result);
    }

    public void checkStalledTasks(OperationResult result) {
        stalledTasksWatcher.checkStalledTasks(result);
    }

    //endregion

    //region Task housekeeping
    public void checkWaitingTasks(OperationResult result) throws SchemaException {
        int count = 0;
        List<Task> tasks = listWaitingTasks(TaskWaitingReason.OTHER_TASKS, result);
        for (Task task : tasks) {
            try {
                ((TaskQuartzImpl) task).checkDependencies(result);
                count++;
            } catch (SchemaException | ObjectNotFoundException e) {
                LoggingUtils.logUnexpectedException(LOGGER, "Couldn't check dependencies for task {}", e, task);
            }
		}
        LOGGER.trace("Check waiting tasks completed; {} tasks checked.", count);
    }

    private List<Task> listWaitingTasks(TaskWaitingReason reason, OperationResult result) throws SchemaException {
		S_AtomicFilterEntry q = QueryBuilder.queryFor(TaskType.class, prismContext);
		q = q.item(TaskType.F_EXECUTION_STATUS).eq(TaskExecutionStatusType.WAITING).and();
		if (reason != null) {
			q = q.item(TaskType.F_WAITING_REASON).eq(reason.toTaskType()).and();
		}
        ObjectQuery query = q.all().build();
        List<PrismObject<TaskType>> prisms = repositoryService.searchObjects(TaskType.class, query, null, result);
        List<Task> tasks = resolveTasksFromTaskTypes(prisms, result);

        result.recordSuccessIfUnknown();
        return tasks;
    }

    // returns map task lightweight id -> task
    public Map<String,TaskQuartzImpl> getLocallyRunningTaskInstances() {
        synchronized (locallyRunningTaskInstancesMap) {    // must be synchronized while iterating over it (addAll)
            return new HashMap<>(locallyRunningTaskInstancesMap);
        }
    }

    public Collection<Task> getTransientSubtasks(TaskQuartzImpl task) {
        List<Task> retval = new ArrayList<>();
        Task runningInstance = locallyRunningTaskInstancesMap.get(task.getTaskIdentifier());
        if (runningInstance != null) {
            retval.addAll(runningInstance.getLightweightAsynchronousSubtasks());
        }
        return retval;
    }

	//endregion
    

	public SecurityContextManager getSecurityContextManager() {
		return securityContextManager;
	}

	public WorkStateManager getWorkStateManager() {
		return workStateManager;
	}

	@Override
	public ObjectQuery narrowQueryForWorkBucket(ObjectQuery query, Class<? extends ObjectType> type,
			Function<ItemPath, ItemDefinition<?>> itemDefinitionProvider, Task workerTask,
			WorkBucketType workBucket, OperationResult opResult)
			throws SchemaException, ObjectNotFoundException {
    	return workStateManager.narrowQueryForWorkBucket(workerTask, query, type, itemDefinitionProvider, workBucket, opResult);
	}

	@Override
	public TaskHandler createAndRegisterPartitioningTaskHandler(String handlerUri, Function<Task, TaskPartitionsDefinition> partitioningStrategy) {
		PartitioningTaskHandler handler = new PartitioningTaskHandler(this, partitioningStrategy);
		registerHandler(handlerUri, handler);
		return handler;
	}

	@Override
	public void setFreeBucketWaitInterval(long value) {
		workStateManager.setFreeBucketWaitIntervalOverride(value);
	}
}