OPENJPA-1722, OPENJPA-1690: Make DistinctResultList serializable, and add writeReplace method.

Submitted by: Dianne Richards and Pinaki Poddar

git-svn-id: https://svn.apache.org/repos/asf/openjpa/branches/2.0.x@979418 13f79535-47bb-0310-9956-ffa450edef68

openjpa-kernel/src/main/java/org/apache/openjpa/kernel/DistinctResultList.java

@@ -18,6 +18,8 @@
  */
 package org.apache.openjpa.kernel;
 
+import java.io.ObjectStreamException;
+import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Iterator;
@@ -39,7 +41,9 @@ import org.apache.openjpa.util.RuntimeExceptionTranslator;
  * @param <E>
  *            element type
  */
-public class DistinctResultList<E> implements List<E> {
+public class DistinctResultList<E> implements List<E>, Serializable {
+    private static final long serialVersionUID = -6140119764940777922L;
+
     private final ArrayList<E> _del;
     private final RuntimeExceptionTranslator _trans;
 
@@ -204,4 +208,9 @@ public class DistinctResultList<E> implements List<E> {
         return (_trans == null) ? re : _trans.translate(re);
     }
 
+    public Object writeReplace()
+        throws ObjectStreamException {
+        return _del;
+    }
+
 }

openjpa-persistence-jdbc/src/test/java/org/apache/openjpa/persistence/query/results/TestListResultSerialization.java

@@ -0,0 +1,59 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.openjpa.persistence.query.results;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.apache.openjpa.lib.rop.ListResultList;
+import org.apache.openjpa.lib.rop.ResultList;
+
+import org.apache.openjpa.kernel.DistinctResultList;
+import org.apache.openjpa.persistence.EntityManagerImpl;
+import org.apache.openjpa.persistence.PersistenceExceptions;
+import org.apache.openjpa.persistence.test.SQLListenerTestCase;
+import org.apache.openjpa.util.RuntimeExceptionTranslator;
+
+/**
+ * Test that the DistinctResultList serializes correctly and without error.
+ *
+ * @since 2.1.0
+ */
+public class TestListResultSerialization extends SQLListenerTestCase {
+    public void setUp() throws Exception {
+        super.setUp();
+        assertNotNull(emf);
+    }
+    
+    public void testRoundtrip() {
+        List<String> list = new ArrayList<String>();
+        list.add("xxx");
+        list.add("yyy");
+        ResultList resultList = new ListResultList(list);
+        EntityManagerImpl em = (EntityManagerImpl)emf.createEntityManager();
+        em.close();
+        RuntimeExceptionTranslator trans = PersistenceExceptions.getRollbackTranslator(em);
+        DistinctResultList distinctResultList = new DistinctResultList(resultList, trans);
+        try {
+            roundtrip(distinctResultList);
+        } catch (Exception e) {
+            e.printStackTrace();
+            fail("unexpected exception - see stack trace in output");
+        }
+    }
+}