Add preliminary <items> correlator

This covers the most basic cases like TestSimpleCorrelationSimplified.

Unrelated changes:
 - Fixed a couple of incorrect uses of Comparator.nullsLast().

infra/schema/src/main/java/com/evolveum/midpoint/schema/util/MatchingUtil.java

@@ -62,10 +62,6 @@ public static Set<String> getValuesForPath(ObjectType object, Object... pathComp
         return getValuesForPath(object.asPrismObject(), ItemPath.create(pathComponents));
     }
 
-    public static Set<String> getValuesForPath(ObjectType object, ItemPath path) {
-        return getValuesForPath(object.asPrismObject(), path);
-    }
-
     public static Set<String> getValuesForPath(PrismObject<?> object, ItemPath path) {
         return object.getAllValues(path).stream()
                 .filter(Objects::nonNull)
@@ -74,6 +70,18 @@ public static Set<String> getValuesForPath(PrismObject<?> object, ItemPath path)
                 .collect(Collectors.toSet());
     }
 
+    public static Set<?> getRealValuesForPath(ObjectType object, ItemPath path) {
+        return getRealValuesForPath(object.asPrismObject(), path);
+    }
+
+    private static Set<?> getRealValuesForPath(PrismObject<?> object, ItemPath path) {
+        return object.getAllValues(path).stream()
+                .filter(Objects::nonNull)
+                .map(PrismValue::getRealValue)
+                .filter(Objects::nonNull)
+                .collect(Collectors.toSet());
+    }
+
     /**
      * Finds a property even if the path was reduced by removing all container IDs.
      *

model/model-api/src/main/java/com/evolveum/midpoint/model/api/correlator/CorrelationContext.java

@@ -183,4 +183,15 @@ public CorrelationContext clone() {
             throw new SystemException(e);
         }
     }
+
+    public @NotNull ObjectType getSourceObject(@NotNull SourceObjectType type) {
+        switch (type) {
+            case FOCUS:
+                return preFocus;
+            case PROJECTION:
+                return resourceObject;
+            default:
+                throw new AssertionError(type);
+        }
+    }
 }

model/model-api/src/main/java/com/evolveum/midpoint/model/api/correlator/CorrelatorConfiguration.java

@@ -42,7 +42,7 @@ public abstract class CorrelatorConfiguration {
         return configurationBean.getOrder();
     }
 
-    public @NotNull String getDebugName() {
+    private @NotNull String getDebugName() {
         return configurationBean.getName() != null ?
                 configurationBean.getName() : getDefaultDebugName();
     }
@@ -120,7 +120,7 @@ private static boolean canBeStandalone(CorrelatorConfiguration configuration) {
     public static List<CorrelatorConfiguration> getConfigurationsSorted(CompositeCorrelatorType correlatorsBean) {
         List<CorrelatorConfiguration> configurations = new ArrayList<>(getConfigurations(correlatorsBean));
         configurations.sort(
-                Comparator.nullsLast(Comparator.comparing(CorrelatorConfiguration::getOrder))
+                Comparator.comparing(CorrelatorConfiguration::getOrder, Comparator.nullsLast(Comparator.naturalOrder()))
                         .thenComparing(CorrelatorConfiguration::getAuthority));
         return configurations;
     }

model/model-api/src/main/java/com/evolveum/midpoint/model/api/correlator/CorrelatorContext.java

@@ -7,6 +7,8 @@
 
 package com.evolveum.midpoint.model.api.correlator;
 
+import com.evolveum.midpoint.util.DebugDumpable;
+
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.annotations.VisibleForTesting;
@@ -21,7 +23,7 @@
  * Differs from {@link CorrelationContext} in that the latter covers only a single correlation operation.
  * The former covers the whole life of a correlator, and operations other than correlation.
  */
-public class CorrelatorContext<C extends AbstractCorrelatorType> {
+public class CorrelatorContext<C extends AbstractCorrelatorType> implements DebugDumpable {
 
     @NotNull private final C configurationBean;
 
@@ -83,4 +85,11 @@ public boolean shouldCreateCases() {
                 && synchronizationBean.getCorrelationDefinition().getCases() != null
                 && !Boolean.FALSE.equals(synchronizationBean.getCorrelationDefinition().getCases().isEnabled());
     }
+
+    @Override
+    public String debugDump(int indent) {
+        // Temporary: this config bean is the core of the context; other things need not be so urgently dumped
+        // (maybe they might be - in some shortened form).
+        return configurationBean.debugDump(indent);
+    }
 }

model/model-api/src/main/java/com/evolveum/midpoint/model/api/correlator/SourceObjectType.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2010-2022 Evolveum and contributors
+ *
+ * This work is dual-licensed under the Apache License 2.0
+ * and European Union Public License. See LICENSE file for details.
+ */
+
+package com.evolveum.midpoint.model.api.correlator;
+
+import com.evolveum.midpoint.schema.constants.ExpressionConstants;
+import com.evolveum.midpoint.util.annotation.Experimental;
+import com.evolveum.midpoint.util.exception.ConfigurationException;
+
+import org.jetbrains.annotations.NotNull;
+
+import javax.xml.namespace.QName;
+
+@Experimental
+public enum SourceObjectType {
+
+    FOCUS, PROJECTION;
+
+    public static SourceObjectType fromVariable(@NotNull QName variableName) throws ConfigurationException {
+        switch (variableName.getLocalPart()) {
+            case ExpressionConstants.VAR_FOCUS:
+            case ExpressionConstants.VAR_USER:
+                return FOCUS;
+            case ExpressionConstants.VAR_PROJECTION:
+            case ExpressionConstants.VAR_SHADOW:
+            case ExpressionConstants.VAR_ACCOUNT:
+                return PROJECTION;
+            default:
+                throw new ConfigurationException("Unsupported variable name: " + variableName);
+        }
+    }
+}

model/model-common/src/main/java/com/evolveum/midpoint/model/common/mapping/metadata/builtin/ProvenanceBuiltinMapping.java

@@ -145,7 +145,9 @@ private ProvenanceMetadataType compute() {
             for (ProvenanceAcquisitionType representativeAcquisition : representativeProvenance.getAcquisition()) {
                 List<ProvenanceAcquisitionType> compatibleAcquisitions = getCompatibleAcquisitions(representativeAcquisition);
                 ProvenanceAcquisitionType earliest = compatibleAcquisitions.stream()
-                        .min(Comparator.nullsLast(Comparator.comparing(acquisition -> XmlTypeConverter.toMillisNullable(acquisition.getTimestamp()))))
+                        .min(Comparator.comparing(
+                                acquisition -> XmlTypeConverter.toMillisNullable(acquisition.getTimestamp()),
+                                Comparator.nullsLast(Comparator.naturalOrder())))
                         .orElseThrow(() -> new IllegalStateException("No earliest acquisition"));
                 resultingProvenance.getAcquisition().add(earliest.clone());
             }

model/model-impl/src/main/java/com/evolveum/midpoint/model/impl/correlator/BaseCorrelator.java

@@ -7,6 +7,11 @@
 
 package com.evolveum.midpoint.model.impl.correlator;
 
+import com.evolveum.midpoint.model.api.correlator.CorrelatorContext;
+
+import com.evolveum.midpoint.model.impl.ModelBeans;
+import com.evolveum.midpoint.xml.ns._public.common.common_3.AbstractCorrelatorType;
+
 import org.jetbrains.annotations.NotNull;
 
 import com.evolveum.midpoint.model.api.correlator.CorrelationContext;
@@ -16,10 +21,43 @@
 import com.evolveum.midpoint.util.exception.*;
 import com.evolveum.midpoint.util.logging.Trace;
 
-public abstract class BaseCorrelator implements Correlator {
+/**
+ * Abstract superclass for non-trivial built-in correlators.
+ *
+ * @param <CCB> correlator configuration bean
+ */
+public abstract class BaseCorrelator<CCB extends AbstractCorrelatorType> implements Correlator {
 
     private static final String OP_CORRELATE_SUFFIX = ".correlate";
 
+    /** Correlator-specific logger. */
+    @NotNull private final Trace logger;
+
+    /** Correlator type name (like "filter", "expression", etc) - for diagnostics purposes. */
+    @NotNull protected final String typeName;
+
+    /** Correlator [instantiation] context. */
+    @NotNull protected final CorrelatorContext<CCB> correlatorContext;
+
+    /** Configuration of the correlator. */
+    @NotNull protected final CCB configurationBean;
+
+    /** Useful beans. */
+    @NotNull protected final ModelBeans beans;
+
+    protected BaseCorrelator(
+            @NotNull Trace logger,
+            @NotNull String typeName,
+            @NotNull CorrelatorContext<CCB> correlatorContext,
+            @NotNull ModelBeans beans) {
+        this.logger = logger;
+        this.typeName = typeName;
+        this.correlatorContext = correlatorContext;
+        this.configurationBean = correlatorContext.getConfigurationBean();
+        this.beans = beans;
+        logger.trace("Instantiating the correlator with the context:\n{}", correlatorContext.debugDumpLazily(1));
+    }
+
     @Override
     public @NotNull CorrelationResult correlate(
             @NotNull CorrelationContext correlationContext, @NotNull OperationResult parentResult)
@@ -29,11 +67,11 @@ public abstract class BaseCorrelator implements Correlator {
         OperationResult result = parentResult.subresult(getClass().getName() + OP_CORRELATE_SUFFIX)
                 .build();
         try {
-            getLogger().trace("Correlating:\n{}", correlationContext.debugDumpLazily(1));
+            logger.trace("Correlating:\n{}", correlationContext.debugDumpLazily(1));
 
             CorrelationResult correlationResult = correlateInternal(correlationContext, result);
 
-            getLogger().trace("Result:\n{}", correlationResult.debugDumpLazily(1));
+            logger.trace("Result:\n{}", correlationResult.debugDumpLazily(1));
 
             result.addArbitraryObjectAsReturn("correlationResult", correlationResult);
 
@@ -51,5 +89,10 @@ public abstract class BaseCorrelator implements Correlator {
             throws ConfigurationException, SchemaException, ExpressionEvaluationException, CommunicationException,
             SecurityViolationException, ObjectNotFoundException;
 
-    protected abstract Trace getLogger();
+    protected @NotNull String getDefaultContextDescription(@NotNull CorrelationContext correlationContext) {
+        return (typeName + " correlator" +
+                (configurationBean.getName() != null ? " '" + configurationBean.getName() + "'" : ""))
+                + " for " + correlationContext.getObjectTypeDefinition().getHumanReadableName()
+                + " in " + correlationContext.getResource();
+    }
 }

model/model-impl/src/main/java/com/evolveum/midpoint/model/impl/correlator/composite/CompositeCorrelator.java

@@ -27,26 +27,19 @@
 import java.util.Objects;
 
 /**
- * TODO
+ * Composite correlator that evaluates its components (child correlators) and builds up the result
+ * according to their results.
  *
  * PRELIMINARY IMPLEMENTATION!
+ *
+ * TODO ignore identifiers in owner options
  */
-class CompositeCorrelator extends BaseCorrelator {
+class CompositeCorrelator extends BaseCorrelator<CompositeCorrelatorType> {
 
     private static final Trace LOGGER = TraceManager.getTrace(CompositeCorrelator.class);
 
-    /**
-     * Configuration of the this correlator.
-     */
-    @NotNull private final CorrelatorContext<CompositeCorrelatorType> correlatorContext;
-
-    /** Useful beans. */
-    @NotNull private final ModelBeans beans;
-
     CompositeCorrelator(@NotNull CorrelatorContext<CompositeCorrelatorType> correlatorContext, @NotNull ModelBeans beans) {
-        this.correlatorContext = correlatorContext;
-        this.beans = beans;
-        LOGGER.trace("Instantiated the correlator with the configuration:\n{}", getConfiguration().debugDumpLazily(1));
+        super(LOGGER, "composite", correlatorContext, beans);
     }
 
     @Override
@@ -55,7 +48,6 @@ class CompositeCorrelator extends BaseCorrelator {
             @NotNull OperationResult result)
             throws SchemaException, ExpressionEvaluationException, CommunicationException, SecurityViolationException,
             ConfigurationException, ObjectNotFoundException {
-
         return new Correlation(correlationContext)
                 .execute(result);
     }
@@ -64,11 +56,6 @@ class CompositeCorrelator extends BaseCorrelator {
         return correlatorContext.getConfigurationBean();
     }
 
-    @Override
-    protected Trace getLogger() {
-        return LOGGER;
-    }
-
     private class Correlation {
 
         @NotNull private final CorrelationContext correlationContext;
@@ -81,11 +68,7 @@ private class Correlation {
         Correlation(@NotNull CorrelationContext correlationContext) {
             this.correlationContext = correlationContext;
             this.task = correlationContext.getTask();
-            this.contextDescription =
-                    ("composite correlator" +
-                            (getConfiguration().getName() != null ? " '" + getConfiguration().getName() + "'" : ""))
-                            + " for " + correlationContext.getObjectTypeDefinition().getHumanReadableName()
-                            + " in " + correlationContext.getResource();
+            this.contextDescription = getDefaultContextDescription(correlationContext);
         }
 
         public CorrelationResult execute(OperationResult result)

model/model-impl/src/main/java/com/evolveum/midpoint/model/impl/correlator/expression/ExpressionCorrelator.java

@@ -13,6 +13,8 @@
 import java.util.List;
 import java.util.Objects;
 
+import com.evolveum.midpoint.model.api.correlator.CorrelatorContext;
+
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -45,22 +47,12 @@
  * A correlator based on expressions that directly provide focal object(s) (or their references) for given resource object.
  * Similar to synchronization sorter, but simpler - it treats only correlation, not the classification part.
  */
-class ExpressionCorrelator extends BaseCorrelator {
+class ExpressionCorrelator extends BaseCorrelator<ExpressionCorrelatorType> {
 
     private static final Trace LOGGER = TraceManager.getTrace(ExpressionCorrelator.class);
 
-    /**
-     * Configuration of the correlator.
-     */
-    @NotNull private final ExpressionCorrelatorType configuration;
-
-    /** Useful beans. */
-    @NotNull private final ModelBeans beans;
-
-    ExpressionCorrelator(@NotNull ExpressionCorrelatorType configuration, @NotNull ModelBeans beans) {
-        this.configuration = configuration;
-        this.beans = beans;
-        LOGGER.trace("Instantiated the correlator with the configuration:\n{}", configuration.debugDumpLazily(1));
+    ExpressionCorrelator(@NotNull CorrelatorContext<ExpressionCorrelatorType> correlatorContext, @NotNull ModelBeans beans) {
+        super(LOGGER, "expression", correlatorContext, beans);
     }
 
     @Override
@@ -74,11 +66,6 @@ class ExpressionCorrelator extends BaseCorrelator {
                 .execute(result);
     }
 
-    @Override
-    protected Trace getLogger() {
-        return LOGGER;
-    }
-
     private class Correlation<F extends FocusType> {
 
         @NotNull private final ShadowType resourceObject;
@@ -92,11 +79,7 @@ private class Correlation<F extends FocusType> {
             this.resourceObject = correlationContext.getResourceObject();
             this.correlationContext = correlationContext;
             this.task = correlationContext.getTask();
-            this.contextDescription =
-                    ("expression correlator" +
-                            (configuration.getName() != null ? " '" + configuration.getName() + "'" : ""))
-                            + " for " + correlationContext.getObjectTypeDefinition().getHumanReadableName()
-                            + " in " + correlationContext.getResource();
+            this.contextDescription = getDefaultContextDescription(correlationContext);
         }
 
         public CorrelationResult execute(OperationResult result)
@@ -112,21 +95,21 @@ public CorrelationResult execute(OperationResult result)
 
             ExpressionType expressionBean;
             ItemDefinition<?> outputDefinition;
-            if (configuration.getOwner() != null) {
-                if (configuration.getOwnerRef() != null) {
+            if (configurationBean.getOwner() != null) {
+                if (configurationBean.getOwnerRef() != null) {
                     throw new ConfigurationException("Both owner and ownerRef expressions found in " + contextDescription);
                 }
-                expressionBean = configuration.getOwner();
+                expressionBean = configurationBean.getOwner();
                 outputDefinition =
                         Objects.requireNonNull(
                                 PrismContext.get().getSchemaRegistry()
                                         .findObjectDefinitionByCompileTimeClass(correlationContext.getFocusType()),
                                 () -> "No definition for focus type " + correlationContext.getFocusType());
             } else {
-                if (configuration.getOwnerRef() == null) {
+                if (configurationBean.getOwnerRef() == null) {
                     throw new ConfigurationException("Neither owner nor ownerRef expression found in " + contextDescription);
                 }
-                expressionBean = configuration.getOwnerRef();
+                expressionBean = configurationBean.getOwnerRef();
                 outputDefinition =
                         PrismContext.get().definitionFactory().createReferenceDefinition(
                                 ExpressionConstants.OUTPUT_ELEMENT_NAME, ObjectReferenceType.COMPLEX_TYPE);

model/model-impl/src/main/java/com/evolveum/midpoint/model/impl/correlator/expression/ExpressionCorrelatorFactory.java

@@ -51,6 +51,6 @@ public void register() {
             @NotNull CorrelatorContext<ExpressionCorrelatorType> context,
             @NotNull Task task,
             @NotNull OperationResult result) throws ConfigurationException {
-        return new ExpressionCorrelator(context.getConfigurationBean(), beans);
+        return new ExpressionCorrelator(context, beans);
     }
 }