Refactor events so listener is defined as an Object for flexibility

git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/collections/trunk@131126 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/commons/collections/decorators/ObservedCollection.java

@@ -1,5 +1,5 @@
 /*
- * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/decorators/Attic/ObservedCollection.java,v 1.2 2003/08/31 17:24:46 scolebourne Exp $
+ * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/decorators/Attic/ObservedCollection.java,v 1.3 2003/08/31 21:09:49 scolebourne Exp $
  * ====================================================================
  *
  * The Apache Software License, Version 1.1
@@ -61,7 +61,6 @@ import java.util.Collection;
 import java.util.Iterator;
 
 import org.apache.commons.collections.event.ModificationHandler;
-import org.apache.commons.collections.event.ModificationListener;
 import org.apache.commons.collections.event.StandardModificationHandler;
 import org.apache.commons.collections.event.StandardModificationListener;
 
@@ -82,7 +81,7 @@ import org.apache.commons.collections.event.StandardModificationListener;
  * uses a technique other than listeners to communicate events.
  *
  * @since Commons Collections 3.0
- * @version $Revision: 1.2 $ $Date: 2003/08/31 17:24:46 $
+ * @version $Revision: 1.3 $ $Date: 2003/08/31 21:09:49 $
  * 
  * @author Stephen Colebourne
  */
@@ -244,7 +243,7 @@ public class ObservedCollection extends AbstractCollectionDecorator {
      * @return the listeners
      * @throws UnsupportedOperationException if the handler does not support listeners
      */
-    public ModificationListener[] getModificationListeners() {
+    public Object[] getModificationListeners() {
         return getHandler().getModificationListeners();
     }
     
@@ -253,12 +252,17 @@ public class ObservedCollection extends AbstractCollectionDecorator {
      * This method simply delegates to the handler.
      * <p>
      * No error occurs if the listener is <code>null</code>.
+     * <p>
+     * The listener does not necessarily have to be a listener in the classic
+     * JavaBean sense. It is entirely up to the handler as to how it interprets
+     * the listener parameter. A ClassCastException is thrown if the handler
+     * cannot interpret the parameter.
      * 
      * @param listener  the listener to add, may be null (ignored)
      * @throws ClassCastException if the listener is not of the correct type
      * @throws UnsupportedOperationException if the handler does not support listeners
      */
-    public void addModificationListener(ModificationListener listener) {
+    public void addModificationListener(Object listener) {
         getHandler().addModificationListener(listener);
     }
     
@@ -274,7 +278,7 @@ public class ObservedCollection extends AbstractCollectionDecorator {
      * @param listener  the listener to remove, may be null (ignored)
      * @throws UnsupportedOperationException if the handler does not support listeners
      */
-    public void removeModificationListener(ModificationListener listener) {
+    public void removeModificationListener(Object listener) {
         getHandler().removeModificationListener(listener);
     }
     

src/java/org/apache/commons/collections/event/ModificationHandler.java

@@ -1,5 +1,5 @@
 /*
- * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/event/Attic/ModificationHandler.java,v 1.2 2003/08/31 17:25:49 scolebourne Exp $
+ * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/event/Attic/ModificationHandler.java,v 1.3 2003/08/31 21:09:49 scolebourne Exp $
  * ====================================================================
  *
  * The Apache Software License, Version 1.1
@@ -69,7 +69,7 @@ import org.apache.commons.collections.decorators.ObservedCollection;
  * that forwards to single points.
  *
  * @since Commons Collections 3.0
- * @version $Revision: 1.2 $ $Date: 2003/08/31 17:25:49 $
+ * @version $Revision: 1.3 $ $Date: 2003/08/31 21:09:49 $
  * 
  * @author Stephen Colebourne
  */
@@ -129,7 +129,7 @@ public abstract class ModificationHandler {
      * @return the listeners
      * @throws UnsupportedOperationException if the handler does not support listeners
      */
-    public ModificationListener[] getModificationListeners() {
+    public Object[] getModificationListeners() {
         throw new UnsupportedOperationException("Listeners not supported by " + getClass().getName());
     }
     
@@ -138,13 +138,18 @@ public abstract class ModificationHandler {
      * <p>
      * No error occurs if the listener is <code>null</code>.
      * <p>
+     * The listener does not necessarily have to be a listener in the classic
+     * JavaBean sense. It is entirely up to the handler as to how it interprets
+     * the listener parameter. A ClassCastException is thrown if the handler
+     * cannot interpret the parameter.
+     * <p>
      * This implementation throws UnsupportedOperationException.
      * 
      * @param listener  the listener to add, may be null (ignored)
      * @throws ClassCastException if the listener is not of the correct type
      * @throws UnsupportedOperationException if the handler does not support listeners
      */
-    public void addModificationListener(ModificationListener listener) {
+    public void addModificationListener(Object listener) {
         throw new UnsupportedOperationException("Listeners not supported by " + getClass().getName());
     }
     
@@ -159,7 +164,7 @@ public abstract class ModificationHandler {
      * @param listener  the listener to remove, may be null (ignored)
      * @throws UnsupportedOperationException if the handler does not support listeners
      */
-    public void removeModificationListener(ModificationListener listener) {
+    public void removeModificationListener(Object listener) {
         throw new UnsupportedOperationException("Listeners not supported by " + getClass().getName());
     }
     

src/java/org/apache/commons/collections/event/ModificationListener.java

@@ -1,77 +0,0 @@
-/*
- * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/event/Attic/ModificationListener.java,v 1.2 2003/08/31 17:25:49 scolebourne Exp $
- * ====================================================================
- *
- * The Apache Software License, Version 1.1
- *
- * Copyright (c) 2003 The Apache Software Foundation.  All rights
- * reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *
- * 3. The end-user documentation included with the redistribution, if
- *    any, must include the following acknowledgement:
- *       "This product includes software developed by the
- *        Apache Software Foundation (http://www.apache.org/)."
- *    Alternately, this acknowledgement may appear in the software itself,
- *    if and wherever such third-party acknowledgements normally appear.
- *
- * 4. The names "The Jakarta Project", "Commons", and "Apache Software
- *    Foundation" must not be used to endorse or promote products derived
- *    from this software without prior written permission. For written
- *    permission, please contact apache@apache.org.
- *
- * 5. Products derived from this software may not be called "Apache"
- *    nor may "Apache" appear in their names without prior written
- *    permission of the Apache Software Foundation.
- *
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
- * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
- * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
- * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- * ====================================================================
- *
- * This software consists of voluntary contributions made by many
- * individuals on behalf of the Apache Software Foundation.  For more
- * information on the Apache Software Foundation, please see
- * <http://www.apache.org/>.
- *
- */
-package org.apache.commons.collections.event;
-
-import java.util.EventListener;
-
-/**
- * An empty listener designed to be subclassed.
- * <p>
- * This interface exists to mark independent subclasses as fulfilling the
- * role of an event listener for collection modification events.
- *
- * @since Commons Collections 3.0
- * @version $Revision: 1.2 $ $Date: 2003/08/31 17:25:49 $
- * 
- * @author Stephen Colebourne
- */
-public interface ModificationListener extends EventListener {
-
-    // no methods - subinterfaces define them
-    
-}

src/java/org/apache/commons/collections/event/StandardModificationHandler.java

@@ -1,5 +1,5 @@
 /*
- * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/event/Attic/StandardModificationHandler.java,v 1.2 2003/08/31 17:25:49 scolebourne Exp $
+ * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/event/Attic/StandardModificationHandler.java,v 1.3 2003/08/31 21:09:49 scolebourne Exp $
  * ====================================================================
  *
  * The Apache Software License, Version 1.1
@@ -80,7 +80,7 @@ package org.apache.commons.collections.event;
  * </ul>
  *
  * @since Commons Collections 3.0
- * @version $Revision: 1.2 $ $Date: 2003/08/31 17:25:49 $
+ * @version $Revision: 1.3 $ $Date: 2003/08/31 21:09:49 $
  * 
  * @author Stephen Colebourne
  */
@@ -123,8 +123,8 @@ public class StandardModificationHandler extends ModificationHandler {
      * 
      * @return the listeners
      */
-    public synchronized ModificationListener[] getModificationListeners() {
+    public synchronized Object[] getModificationListeners() {
-        ModificationListener[] lnrs = new ModificationListener[holders.length];
+        Object[] lnrs = new Object[holders.length];
         for (int i = 0; i < holders.length; i++) {
             lnrs[i] = holders[i].listener;
         }
@@ -139,8 +139,8 @@ public class StandardModificationHandler extends ModificationHandler {
      * @param listener  the listener to add, may be null (ignored)
      * @throws ClassCastException if the listener is not a StandardModificationListener
      */
-    public void addModificationListener(ModificationListener listener) {
+    public void addModificationListener(Object listener) {
-        addModificationListener(listener, -1, -1);
+        addModificationListener((StandardModificationListener) listener, -1, -1);
     }
     
     /**
@@ -151,14 +151,13 @@ public class StandardModificationHandler extends ModificationHandler {
      * @param listener  the listener to add, may be null (ignored)
      * @param preMask  the mask for pre events (0 for none, -1 for all)
      * @param postMask  the mask for post events (0 for none, -1 for all)
-     * @throws ClassCastException if the listener is not a StandardModificationListener
      */
-    public synchronized void addModificationListener(ModificationListener listener, int preMask, int postMask) {
+    public synchronized void addModificationListener(StandardModificationListener listener, int preMask, int postMask) {
         if (listener != null) {
             int oldSize = holders.length;
             Holder[] array = new Holder[oldSize + 1];
             System.arraycopy(holders, 0, array, 0, oldSize);
-            array[oldSize] = new Holder((StandardModificationListener) listener, preMask, postMask);
+            array[oldSize] = new Holder(listener, preMask, postMask);
             holders = array;
             calculateMasks();
         }
@@ -173,7 +172,7 @@ public class StandardModificationHandler extends ModificationHandler {
      * 
      * @param listener  the listener to remove, may be null (ignored)
      */
-    public synchronized void removeModificationListener(ModificationListener listener) {
+    public synchronized void removeModificationListener(Object listener) {
         if (listener != null) {
             switch (holders.length) {
                 case 0:

src/java/org/apache/commons/collections/event/StandardModificationListener.java

@@ -1,5 +1,5 @@
 /*
- * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/event/Attic/StandardModificationListener.java,v 1.2 2003/08/31 17:25:49 scolebourne Exp $
+ * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/event/Attic/StandardModificationListener.java,v 1.3 2003/08/31 21:09:49 scolebourne Exp $
  * ====================================================================
  *
  * The Apache Software License, Version 1.1
@@ -57,6 +57,8 @@
  */
 package org.apache.commons.collections.event;
 
+import java.util.EventListener;
+
 /**
  * A listener that receives events from the <code>StandardModificationHandler</code>.
  * <p>
@@ -69,11 +71,11 @@ package org.apache.commons.collections.event;
  * </ol>
  *
  * @since Commons Collections 3.0
- * @version $Revision: 1.2 $ $Date: 2003/08/31 17:25:49 $
+ * @version $Revision: 1.3 $ $Date: 2003/08/31 21:09:49 $
  * 
  * @author Stephen Colebourne
  */
-public interface StandardModificationListener extends ModificationListener {
+public interface StandardModificationListener extends EventListener {
 
     /**
      * A collection modification is occurring.

src/test/org/apache/commons/collections/decorators/ObservedTestHelper.java

@@ -1,5 +1,5 @@
 /*
- * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/test/org/apache/commons/collections/decorators/Attic/ObservedTestHelper.java,v 1.2 2003/08/31 17:28:42 scolebourne Exp $
+ * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/test/org/apache/commons/collections/decorators/Attic/ObservedTestHelper.java,v 1.3 2003/08/31 21:09:49 scolebourne Exp $
  * ====================================================================
  *
  * The Apache Software License, Version 1.1
@@ -64,7 +64,6 @@ import java.util.List;
 import junit.framework.Assert;
 
 import org.apache.commons.collections.event.ModificationEventType;
-import org.apache.commons.collections.event.ModificationListener;
 import org.apache.commons.collections.event.StandardModificationEvent;
 import org.apache.commons.collections.event.StandardModificationHandler;
 import org.apache.commons.collections.event.StandardModificationListener;
@@ -74,7 +73,7 @@ import org.apache.commons.collections.event.StandardModificationListener;
  * {@link ObservedCollection} implementations.
  *
  * @since Commons Collections 3.0
- * @version $Revision: 1.2 $ $Date: 2003/08/31 17:28:42 $
+ * @version $Revision: 1.3 $ $Date: 2003/08/31 21:09:49 $
  * 
  * @author Stephen Colebourne
  */
@@ -157,7 +156,7 @@ public class ObservedTestHelper {
         Assert.assertEquals(0, coll.getModificationListeners().length);
         
         try {
-            coll.addModificationListener(new ModificationListener() {});
+            coll.addModificationListener(new Object());
             Assert.fail();
         } catch (ClassCastException ex) {
         }