Fix #1240: SessionEventListener: add pre/post flush() events (#1978)

* Fixes #1240 : SessionEventListener: add pre/post flush() events
- added preFlushUnitOfWork/postFlushUnitOfWork events
- removed preCommitUnitOfWork event from flush in UnitOfWorkImpl
- added unitTests for flush events

Signed-off-by: Patrick Schmitt <Patrick.Schmitt@cpb-software.com>

foundation/eclipselink.core.test/src/it/java/org/eclipse/persistence/testing/tests/events/SessionEventTestCase.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2021 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2023 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
@@ -43,6 +43,7 @@ public void test() {
         UnitOfWork uow = getSession().acquireUnitOfWork();
         Employee emp = (Employee)uow.readObject(Employee.class);
         emp.setFirstName(emp.getFirstName() + "-modified");
+        uow.writeChanges();
         uow.commit();
     }
 
@@ -60,5 +61,11 @@ public void verify() {
         if (this.listener.postAcquireClientSession) {
             throw new TestErrorException("The post acquire event was not raised but should not have been.");
         }
+        if(!this.listener.preFlushUnitOfWork) {
+            throw new TestErrorException("The pre UnitOfWork flush event did not fire");
+        }
+        if(!this.listener.postFlushUnitOfWork) {
+            throw new TestErrorException("The post UnitOfWork flush event did not fire");
+        }
     }
 }

foundation/eclipselink.core.test/src/it/java/org/eclipse/persistence/testing/tests/events/TestSessionListener.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2021 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2023 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
@@ -22,6 +22,18 @@ public class TestSessionListener extends SessionEventAdapter {
     public boolean preBeginTransaction;
     public boolean postCalculateUnitOfWork;
     public boolean preCalculateUnitOfWork;
+    public boolean preFlushUnitOfWork;
+    public boolean postFlushUnitOfWork;
+
+    @Override
+    public void postFlushUnitOfWork(SessionEvent event) {
+       postFlushUnitOfWork = true;
+    }
+
+    @Override
+    public void preFlushUnitOfWork(SessionEvent event) {
+        preFlushUnitOfWork = true;
+    }
 
     /**
      * TestSessionListener constructor comment.

foundation/eclipselink.core.test/src/it/java/org/eclipse/persistence/testing/tests/unitofwork/PostFlushUnitOfWorkTest.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2023 Oracle and/or its affiliates. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0,
+ * or the Eclipse Distribution License v. 1.0 which is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
+ */
+package org.eclipse.persistence.testing.tests.unitofwork;
+
+import org.eclipse.persistence.sessions.SessionEvent;
+import org.eclipse.persistence.sessions.SessionEventAdapter;
+import org.eclipse.persistence.sessions.UnitOfWork;
+import org.eclipse.persistence.testing.framework.TestErrorException;
+
+public class PostFlushUnitOfWorkTest extends UnitOfWorkEventTest {
+    @Override
+    public void setup() {
+        super.setup();
+        setDescription("Test the postFlushUnitOfWork Event");
+        SessionEventAdapter tvAdapter = new SessionEventAdapter() {
+                // Listen for PostFlushUnitOfWorkEvents
+
+                @Override
+                public void postFlushUnitOfWork(SessionEvent event) {
+                    setEventTriggered(true);
+                }
+            };
+        getSession().getEventManager().addListener(tvAdapter);
+    }
+
+    @Override
+    public void test() {
+        UnitOfWork tvUnitOfWork = getSession().acquireUnitOfWork();
+        tvUnitOfWork.writeChanges();
+    }
+
+    @Override
+    public void verify() {
+        if (!isEventTriggered()) {
+            throw new TestErrorException("The preFlushUnitOfWork event was not triggered.");
+        }
+    }
+}

foundation/eclipselink.core.test/src/it/java/org/eclipse/persistence/testing/tests/unitofwork/PreFlushUnitOfWorkTest.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2023 Oracle and/or its affiliates. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0,
+ * or the Eclipse Distribution License v. 1.0 which is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
+ */
+package org.eclipse.persistence.testing.tests.unitofwork;
+
+import org.eclipse.persistence.sessions.SessionEvent;
+import org.eclipse.persistence.sessions.SessionEventAdapter;
+import org.eclipse.persistence.sessions.UnitOfWork;
+import org.eclipse.persistence.testing.framework.TestErrorException;
+
+public class PreFlushUnitOfWorkTest extends UnitOfWorkEventTest {
+    @Override
+    public void setup() {
+        super.setup();
+        setDescription("Test the preFlushUnitOfWork Event");
+        SessionEventAdapter tvAdapter = new SessionEventAdapter() {
+                // Listen for PreFlushUnitOfWorkEvents
+
+                @Override
+                public void preFlushUnitOfWork(SessionEvent event) {
+                    setEventTriggered(true);
+                }
+            };
+        getSession().getEventManager().addListener(tvAdapter);
+    }
+
+    @Override
+    public void test() {
+        UnitOfWork tvUnitOfWork = getSession().acquireUnitOfWork();
+        tvUnitOfWork.writeChanges();
+    }
+
+    @Override
+    public void verify() {
+        if (!isEventTriggered()) {
+            throw new TestErrorException("The preFlushUnitOfWork event was not triggered.");
+        }
+    }
+}

foundation/eclipselink.core.test/src/it/java/org/eclipse/persistence/testing/tests/unitofwork/UnitOfWorkEventTestSuite.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2021 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2023 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
@@ -29,6 +29,12 @@ public void addTests() {
         // PreCommitUnitOfWork
         addTest(new PreCommitUnitOfWorkTest());
 
+        // PreFlushUnitOfWork
+        addTest(new PreFlushUnitOfWorkTest());
+
+        // PostFlushUnitOfWork
+        addTest(new PostFlushUnitOfWorkTest());
+
         // PrepareUnitOfWork
         addTest(new PrepareUnitOfWorkTest());
 

foundation/org.eclipse.persistence.core.test.framework/src/main/java/org/eclipse/persistence/testing/framework/SessionEventTracker.java

@@ -414,6 +414,17 @@ public void postCommitUnitOfWork(SessionEvent event) {
         log(event);
     }
 
+    /**
+     * PUBLIC: This event is raised on the unit of work after a flush.
+     */
+    @Override
+    public void postFlushUnitOfWork(SessionEvent event) {
+        if (!isTrackingEvent(event)) {
+            return;
+        }
+        log(event);
+    }
+
     /**
      * PUBLIC:
      * This event is raised after the session connects to the database.
@@ -568,6 +579,17 @@ public void preCommitUnitOfWork(SessionEvent event) {
         log(event);
     }
 
+    /**
+     * PUBLIC: This event is raised on the unit of work before a flush.
+     */
+    @Override
+    public void preFlushUnitOfWork(SessionEvent event) {
+        if (!isTrackingEvent(event)) {
+            return;
+        }
+        log(event);
+    }
+
     /**
      * PUBLIC:
      * This event is raised before the execution of every query against the session.

foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/internal/sessions/RepeatableWriteUnitOfWork.java

@@ -441,6 +441,9 @@ public void writeChanges() {
             return;
         }
         log(SessionLog.FINER, SessionLog.TRANSACTION, "begin_unit_of_work_flush");
+        if(eventManager != null) {
+            eventManager.preFlushUnitOfWork();
+        }
 
         // 256277: stop any nested flushing - there should only be one level
         this.isWithinFlush = true; // set before calculateChanges as a PrePersist callback may contain a query that requires a pre flush()
@@ -465,6 +468,9 @@ public void writeChanges() {
                 writesCompleted();
                 //return if there were no changes in the change set.
                 log(SessionLog.FINER, SessionLog.TRANSACTION, "end_unit_of_work_flush");
+                if(eventManager != null) {
+                    eventManager.postFlushUnitOfWork();
+                }
                 return;
             }
             // Write changes to the database.
@@ -485,6 +491,9 @@ public void writeChanges() {
             this.cumulativeUOWChangeSet.mergeUnitOfWorkChangeSet(changeSet, this, true);
         }
         log(SessionLog.FINER, SessionLog.TRANSACTION, "end_unit_of_work_flush");
+        if(eventManager != null) {
+            eventManager.postFlushUnitOfWork();
+        }
 
         resumeUnitOfWork();
         log(SessionLog.FINER, SessionLog.TRANSACTION, "resume_unit_of_work");

foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/internal/sessions/UnitOfWorkImpl.java

@@ -5856,10 +5856,11 @@ public void writeChanges() {
             throw ValidationException.writeChangesOnNestedUnitOfWork();
         }
         log(SessionLog.FINER, SessionLog.TRANSACTION, "begin_unit_of_work_flush");
-        mergeBmpAndWsEntities();
         if (this.eventManager != null) {
-            this.eventManager.preCommitUnitOfWork();
+            this.eventManager.preFlushUnitOfWork();
         }
+        mergeBmpAndWsEntities();
+
         setLifecycle(CommitPending);
         try {
             commitToDatabaseWithChangeSet(false);
@@ -5871,6 +5872,9 @@ public void writeChanges() {
         }
         setLifecycle(CommitTransactionPending);
         log(SessionLog.FINER, SessionLog.TRANSACTION, "end_unit_of_work_flush");
+        if (this.eventManager != null) {
+            this.eventManager.postFlushUnitOfWork();
+        }
     }
 
     /**

foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/internal/sessions/remote/RemoteUnitOfWork.java

@@ -225,6 +225,9 @@ public void writeChanges() {
             return;
         }
         log(SessionLog.FINER, SessionLog.TRANSACTION, "begin_unit_of_work_flush");
+        if(eventManager != null) {
+            eventManager.preFlushUnitOfWork();
+        }
 
         // PERF: If this is an empty unit of work, do nothing (but still may need to commit SQL changes).
         boolean hasChanges = (this.unitOfWorkChangeSet != null) || hasCloneMapping() || hasDeletedObjects() || hasModifyAllQueries() || hasDeferredModifyAllQueries();
@@ -238,6 +241,9 @@ public void writeChanges() {
         }
         if (!hasChanges) {
             log(SessionLog.FINER, SessionLog.TRANSACTION, "end_unit_of_work_flush");
+            if(eventManager != null) {
+                eventManager.postFlushUnitOfWork();
+            }
             return;
         }
 
@@ -268,6 +274,9 @@ public void writeChanges() {
         remoteUnitOfWork.commitIntoRemoteUnitOfWork();
 
         log(SessionLog.FINER, SessionLog.TRANSACTION, "end_unit_of_work_flush");
+        if(eventManager != null) {
+            eventManager.postFlushUnitOfWork();
+        }
 
         resumeUnitOfWork();
         log(SessionLog.FINER, SessionLog.TRANSACTION, "resume_unit_of_work");

foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/sessions/SessionEvent.java

@@ -69,6 +69,10 @@ public class SessionEvent extends EventObject {
     public static final int PrepareUnitOfWork = 14;
     public static final int PostResumeUnitOfWork = 15;
 
+    public static final int PreFlushUnitOfWork = 38;
+
+    public static final int PostFlushUnitOfWork = 39;
+
     // Three-tier events, only raised on server/client session.
     public static final int PostAcquireClientSession = 16;
     public static final int PreReleaseClientSession = 17;

foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/sessions/SessionEventAdapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2021 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2023 Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2021 IBM Corporation. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
@@ -65,6 +65,9 @@ public void postCommitTransaction(SessionEvent event) { }
     @Override
     public void postCommitUnitOfWork(SessionEvent event) { }
 
+    @Override
+    public void postFlushUnitOfWork(SessionEvent event) { }
+
     @Override
     public void postDistributedMergeUnitOfWorkChangeSet(SessionEvent event) { }
 
@@ -101,6 +104,9 @@ public void preCommitTransaction(SessionEvent event) { }
     @Override
     public void preCommitUnitOfWork(SessionEvent event) { }
 
+    @Override
+    public void preFlushUnitOfWork(SessionEvent event) { }
+
     @Override
     public void preExecuteCall(SessionEvent event) { }
 

foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/sessions/SessionEventListener.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2021 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2023 Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2021 IBM Corporation. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
@@ -124,6 +124,11 @@ public interface SessionEventListener extends CoreSessionEventListener {
      */
     void postCommitUnitOfWork(SessionEvent event);
 
+    /**
+     * PUBLIC: This event is raised on the unit of work after a flush.
+     */
+    void postFlushUnitOfWork(SessionEvent event);
+
     /**
      * PUBLIC:
      * This event is raised after the session connects to the database.
@@ -207,6 +212,11 @@ public interface SessionEventListener extends CoreSessionEventListener {
      */
     void preCommitUnitOfWork(SessionEvent event);
 
+    /**
+     * PUBLIC: This event is raised on the unit of work before a flush.
+     */
+    void preFlushUnitOfWork(SessionEvent event);
+
     /**
      * PUBLIC:
      * This event is raised before the execution of every call against the session.