Making MultiValueMap serializable as per COLLECTIONS-240

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/collections/trunk@656960 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/commons/collections/map/MultiValueMap.java

@@ -16,6 +16,11 @@
  */
 package org.apache.commons.collections.map;
 
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
+
 import java.util.AbstractCollection;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -61,7 +66,10 @@ import org.apache.commons.collections.iterators.IteratorChain;
  * @version $Revision$ $Date$
  * @since Commons Collections 3.2
  */
-public class MultiValueMap extends AbstractMapDecorator implements MultiMap {
+public class MultiValueMap extends AbstractMapDecorator implements MultiMap, Serializable {
+
+    /** Serialization version */
+    private static final long serialVersionUID = -2214159910087182007L;
 
     /** The factory for creating value collections. */
     private final Factory collectionFactory;
@@ -124,6 +132,32 @@ public class MultiValueMap extends AbstractMapDecorator implements MultiMap {
         this.collectionFactory = collectionFactory;
     }
 
+    //-----------------------------------------------------------------------
+    /**
+     * Write the map out using a custom routine.
+     * 
+     * @param out  the output stream
+     * @throws IOException
+     * @since Commons Collections 3.3
+     */
+    private void writeObject(ObjectOutputStream out) throws IOException {
+        out.defaultWriteObject();
+        out.writeObject(map);
+    }
+
+    /**
+     * Read the map in using a custom routine.
+     * 
+     * @param in  the input stream
+     * @throws IOException
+     * @throws ClassNotFoundException
+     * @since Commons Collections 3.3
+     */
+    private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
+        in.defaultReadObject();
+        map = (Map) in.readObject();
+    }
+
     //-----------------------------------------------------------------------
     /**
      * Clear the map.
@@ -424,7 +458,7 @@ public class MultiValueMap extends AbstractMapDecorator implements MultiMap {
     /**
      * Inner class that provides a simple reflection factory.
      */
-    private static class ReflectionFactory implements Factory {
+    private static class ReflectionFactory implements Factory, Serializable {
         private final Class clazz;
 
         public ReflectionFactory(Class clazz) {

src/test/org/apache/commons/collections/map/TestMultiValueMap.java

@@ -32,6 +32,8 @@ import junit.framework.TestSuite;
 import org.apache.commons.collections.IteratorUtils;
 import org.apache.commons.collections.MultiMap;
 
+import org.apache.commons.collections.AbstractTestObject;
+
 /**
  * TestMultiValueMap.
  *
@@ -39,7 +41,7 @@ import org.apache.commons.collections.MultiMap;
  * @author Stephen Colebourne
  * @since Commons Collections 3.2
  */
-public class TestMultiValueMap extends TestCase {
+public class TestMultiValueMap extends AbstractTestObject {
 
     public TestMultiValueMap(String testName) {
         super(testName);
@@ -353,4 +355,55 @@ public class TestMultiValueMap extends TestCase {
         assertEquals(new MultiValueMap(), map);
     }
 
+    //-----------------------------------------------------------------------
+    // Manual serialization testing as this class cannot easily 
+    // extend the AbstractTestMap
+    //-----------------------------------------------------------------------
+
+    public String getCompatibilityVersion() {
+        return "3.3";
+    }
+
+    public Object makeObject() {
+        Map m = makeEmptyMap();
+        m.put("a", "1");
+        m.put("a", "1b");
+        m.put("b", "2");
+        m.put("c", "3");
+        m.put("c", "3b");
+        m.put("d", "4");
+        return m;
+    }
+
+    private Map makeEmptyMap() {
+        return new MultiValueMap();
+    }
+
+//    public void testCreate() throws Exception {
+//        writeExternalFormToDisk(
+//            (java.io.Serializable) makeEmptyMap(),
+//            "/tmp/MultiValueMap.emptyCollection.version3.3.obj");
+//
+//        writeExternalFormToDisk(
+//            (java.io.Serializable) makeObject(),
+//            "/tmp/MultiValueMap.fullCollection.version3.3.obj");
+//    }
+
+    public void testEmptyMapCompatibility() throws Exception {
+        Map map = makeEmptyMap();
+        Map map2 = (Map) readExternalFormFromDisk(getCanonicalEmptyCollectionName(map));
+        assertEquals("Map is empty", 0, map2.size());
+    }
+    public void testFullMapCompatibility() throws Exception {
+        Map map = (Map) makeObject();
+        Map map2 = (Map) readExternalFormFromDisk(getCanonicalFullCollectionName(map));
+        assertEquals("Map is the right size", map.size(), map2.size());
+        for (Iterator it = map.keySet().iterator(); it.hasNext();) {
+            Object key = it.next();
+            assertEquals( "Map had inequal elements", map.get(key), map2.get(key) );
+            map2.remove(key);
+        }
+        assertEquals("Map had extra values", 0, map2.size());
+    }
+
 }