Refactor child workflow saving to work via StateExecution

nflow-engine/src/main/java/com/nitorcreations/nflow/engine/internal/executor/WorkflowStateProcessor.java

@@ -106,10 +106,10 @@ private void runImpl() {
         rescheduleUnknownWorkflowState(instance);
         return;
       }
-      NextAction nextAction = null;
+
       try {
         processBeforeListeners(listenerContext);
-        nextAction = processState(instance, definition, execution, state);
+        NextAction nextAction = processState(instance, definition, execution, state);
         if (listenerContext != null) {
           listenerContext.nextAction = nextAction;
         }
@@ -127,7 +127,7 @@ private void runImpl() {
           processAfterListeners(listenerContext);
         }
         subsequentStateExecutions = busyLoopPrevention(settings, subsequentStateExecutions, execution);
-        instance = saveWorkflowInstanceState(execution, instance, definition, nextAction, actionBuilder);
+        instance = saveWorkflowInstanceState(execution, instance, definition, actionBuilder);
       }
     }
     logger.debug("Finished.");
@@ -174,7 +174,7 @@ private int busyLoopPrevention(WorkflowSettings settings,
   }
 
   private WorkflowInstance saveWorkflowInstanceState(StateExecutionImpl execution, WorkflowInstance instance,
-      WorkflowDefinition<?> definition, NextAction nextAction, WorkflowInstanceAction.Builder actionBuilder) {
+      WorkflowDefinition<?> definition, WorkflowInstanceAction.Builder actionBuilder) {
     if (definition.getMethod(execution.getNextState()) == null && execution.getNextActivation() != null) {
       logger.info("No handler method defined for {}, clearing next activation", execution.getNextState());
       execution.setNextActivation(null);
@@ -187,9 +187,8 @@ private WorkflowInstance saveWorkflowInstanceState(StateExecutionImpl execution,
       .setRetries(execution.isRetry() ? execution.getRetries() + 1 : 0);
     actionBuilder.setExecutionEnd(now()).setType(getActionType(execution)).setStateText(execution.getNextStateReason());
 
-    // TODO this null check is due to lazy test writer
-    List<WorkflowInstance> childWorkflows = nextAction != null ? nextAction.getChildWorkflows() : Arrays.<WorkflowInstance>asList();
-    workflowInstanceDao.updateWorkflowInstanceAfterExecution(builder.build(), actionBuilder.build(), childWorkflows);
+    workflowInstanceDao.updateWorkflowInstanceAfterExecution(builder.build(), actionBuilder.build(),
+            execution.getNewChildWorkflows());
     return builder.setOriginalStateVariables(instance.stateVariables).build();
   }
 

nflow-engine/src/main/java/com/nitorcreations/nflow/engine/internal/workflow/StateExecutionImpl.java

@@ -9,6 +9,8 @@
 import com.nitorcreations.nflow.engine.workflow.definition.WorkflowState;
 import com.nitorcreations.nflow.engine.workflow.instance.WorkflowInstance;
 
+import java.util.Collections;
+import java.util.LinkedList;
 import java.util.List;
 
 public class StateExecutionImpl implements StateExecution {
@@ -23,6 +25,7 @@ public class StateExecutionImpl implements StateExecution {
   private Throwable thrown;
   private boolean isFailed;
   private boolean isRetryCountExceeded;
+  private List<WorkflowInstance> newChildWorkflows = new LinkedList<>();
 
   public StateExecutionImpl(WorkflowInstance instance, ObjectStringMapper objectMapper, WorkflowInstanceDao workflowDao) {
     this.instance = instance;
@@ -141,9 +144,21 @@ public void setRetryCountExceeded() {
     isRetryCountExceeded = true;
   }
 
+  public void addChildWorkflows(WorkflowInstance ... childWorkflows) {
+    Assert.notNull(childWorkflows, "childWorkflows can not be null");
+    for(WorkflowInstance child : childWorkflows) {
+      Assert.notNull(child, "childWorkflow can not be null");
+      newChildWorkflows.add(child);
+    }
+  }
+
+  public List<WorkflowInstance> getNewChildWorkflows() {
+    return Collections.unmodifiableList(newChildWorkflows);
+  }
+
   // TODO add tests
   @Override
-  public List<WorkflowInstance> getChildWorkflows(QueryWorkflowInstances query) {
+  public List<WorkflowInstance> queryChildWorkflows(QueryWorkflowInstances query) {
     QueryWorkflowInstances restrictedQuery = new QueryWorkflowInstances.Builder(query)
             .setParentWorkflowId(instance.id).build();
     return workflowDao.queryWorkflowInstances(restrictedQuery);

nflow-engine/src/main/java/com/nitorcreations/nflow/engine/workflow/definition/NextAction.java

@@ -2,32 +2,20 @@
 
 import static org.joda.time.DateTime.now;
 
-import com.nitorcreations.nflow.engine.workflow.instance.WorkflowInstance;
 import org.joda.time.DateTime;
 
 import com.nitorcreations.nflow.engine.internal.executor.InvalidNextActionException;
 
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
-
 public class NextAction {
 
   private final DateTime activation;
   private final WorkflowState nextState;
   private final String reason;
-  private final List<WorkflowInstance> childWorkflows;
 
   private NextAction(DateTime activation, WorkflowState nextState, String reason) {
-    this(activation, nextState, Arrays.<WorkflowInstance>asList(), reason);
-  }
-
-  private NextAction(DateTime activation, WorkflowState nextState,
-                     List<WorkflowInstance> childWorkflows, String reason) {
     this.reason = reason;
     this.nextState = nextState;
     this.activation = activation;
-    this.childWorkflows = Collections.unmodifiableList(childWorkflows);
   }
 
   /**
@@ -79,22 +67,6 @@ public static NextAction moveToStateAfter(WorkflowState nextState, DateTime acti
     return new NextAction(activation, nextState, reason);
   }
 
-  /**
-   * Schedule processing of state {@code nextState} at time {@code activation}.
-   * @param nextState The next workflow state.
-   * @param activation The time after which the workflow can be activated.
-   * @param childWorkflows list of child workflows to create.
-   * @param reason The reason for the action.
-   * @return A valid {@code NextAction} value.
-   */
-  public static NextAction moveToStateAfter(WorkflowState nextState, DateTime activation,
-                                            List<WorkflowInstance> childWorkflows, String reason) {
-    assertNotNull(nextState, "Next state can not be null");
-    assertNotNull(activation, "Activation can not be null");
-    assertNotNull(childWorkflows, "childWorkflows can not be null");
-    return new NextAction(activation, nextState, childWorkflows, reason);
-  }
-
   /**
    * Schedule processing of state {@code nextState} immediately.
    * @param nextState The next workflow state.
@@ -106,19 +78,6 @@ public static NextAction moveToState(WorkflowState nextState, String reason) {
     return new NextAction(now(), nextState, reason);
   }
 
-  /**
-   * Schedule processing of state {@code nextState} immediately.
-   * @param nextState The next workflow state.
-   * @param childWorkflows list of child workflows to create.
-   * @param reason The reason for the action.
-   * @return A valid {@code NextAction} value.
-   */
-  public static NextAction moveToState(WorkflowState nextState, List<WorkflowInstance> childWorkflows, String reason) {
-    assertNotNull(nextState, "Next state can not be null");
-    assertNotNull(childWorkflows, "childWorkflows can not be null");
-    return new NextAction(now(), nextState, childWorkflows, reason);
-  }
-
   /**
    * Set next state to {@code finalState} and do not schedule its
    * processing. The {@code finalState} workflow state type must
@@ -158,12 +117,4 @@ public boolean isRetry() {
     return nextState == null;
   }
 
-  /**
-   * Return list of child workflows.
-   * @return list of child workflows.
-   */
-  public List<WorkflowInstance> getChildWorkflows() {
-    return childWorkflows;
-  }
-
 }

nflow-engine/src/main/java/com/nitorcreations/nflow/engine/workflow/definition/StateExecution.java

@@ -87,11 +87,19 @@ public interface StateExecution {
    */
   String getWorkflowInstanceExternalId();
 
+  /**
+   * Add a new child workflow. Child workflows are stored to database scheduled after current
+   * state method exists successfully.
+   * Note that Child workflows are not visible to queryChildWorkflows() method before they are stored to database.
+   * @param childWorkflows
+   */
+  void addChildWorkflows(WorkflowInstance ... childWorkflows);
+
   /**
    * Return child workflow instances for current workflow. Query is restricted to childs of current workflow.
    * @param query The query criterias.
    * @return List of child workflows that match the query.
    */
-  List<WorkflowInstance> getChildWorkflows(QueryWorkflowInstances query);
+  List<WorkflowInstance> queryChildWorkflows(QueryWorkflowInstances query);
 
 }

nflow-tests/src/main/java/com/nitorcreations/nflow/tests/demo/FibonacciWorkflow.java

@@ -86,8 +86,8 @@ private NextAction nextStep(StateExecution execution, int nextN, int offset, Sta
 
         execution.setVariable("childrenCount", String.valueOf(getChildrenCount(execution) + 1));
         logger.info("Create child workflow N={}", nextN);
-        List<WorkflowInstance> childWorkflows = Arrays.asList(createWorkflow(nextN));
-        return NextAction.moveToState(nextState, childWorkflows, "Creating childWorkflow to process f(" + nextN + ")");
+        execution.addChildWorkflows(createWorkflow(nextN));
+        return NextAction.moveToState(nextState, "Creating childWorkflow to process f(" + nextN + ")");
     }
 
     private int getChildrenCount(StateExecution execution) {
@@ -100,7 +100,7 @@ private int getChildrenCount(StateExecution execution) {
 
     public NextAction poll(StateExecution execution, @StateVar(value="requestData") int n) {
         // get finished and failed child workflows
-        List<WorkflowInstance> children = execution.getChildWorkflows(new QueryWorkflowInstances.Builder()
+        List<WorkflowInstance> children = execution.queryChildWorkflows(new QueryWorkflowInstances.Builder()
                 .addStatuses(manual.getStatus(), end.getStatus()).build());
         if(children.size() < getChildrenCount(execution)) {
             int delay = new Random().nextInt(5) + 1;