Type-safe result listeners. Whee!

git-svn-id: https://samskivert.googlecode.com/svn/trunk@1832 6335cc39-0255-0410-8fd6-9bcaacd3b74c

src/java/com/samskivert/util/ResultListener.java

@@ -16,7 +16,7 @@ package com.samskivert.util;
  * more clearly than the previous paragraph of flowery prose:
  *
  * <pre>
- * public void doSomeStuff (ResultListener listener)
+ * public void doSomeStuff (ResultListener<String> listener)
  * {
  *     Runnable run = new Runnable () {
  *         public void run () {
@@ -34,26 +34,17 @@ package com.samskivert.util;
  *
  * @see IntResultListener
  */
-public interface ResultListener
+public interface ResultListener<T>
 {
     /**
      * Called to communicate that the request succeeded and that the
      * result is available.
      */
-    public void requestCompleted (Object result);
+    public void requestCompleted (T result);
 
     /**
      * Called to communicate that the request failed and to provide the
      * reason for failure.
      */
     public void requestFailed (Exception cause);
-
-    /** Useful when you want to allow optional result listeners but don't
-     * want to have to check before calling. */
-    public static final ResultListener NOOP = new ResultListener() {
-        public void requestCompleted (Object result) {
-        }
-        public void requestFailed (Exception cause) {
-        }
-    };
 }

src/java/com/samskivert/util/ResultListenerList.java

@@ -6,8 +6,8 @@ package com.samskivert.util;
 /**
  * Multiplexes ResultListener responses to multiple ResultListeners.
  */
-public class ResultListenerList extends ObserverList<ResultListener>
-    implements ResultListener
+public class ResultListenerList<T> extends ObserverList<ResultListener<T>>
+    implements ResultListener<T>
 {
     /**
      * Create a ResultListenerList with the FAST_UNSAFE_NOTIFY policy.
@@ -29,10 +29,10 @@ public class ResultListenerList extends ObserverList<ResultListener>
      * Multiplex a requestCompleted response to all the ResultListeners in
      * this list.
      */
-    public void requestCompleted (final Object result)
+    public void requestCompleted (final T result)
     {
-        apply(new ObserverOp<ResultListener>() {
-            public boolean apply (ResultListener observer) {
+        apply(new ObserverOp<ResultListener<T>>() {
+            public boolean apply (ResultListener<T> observer) {
                 observer.requestCompleted(result);
                 return true;
             }
@@ -45,8 +45,8 @@ public class ResultListenerList extends ObserverList<ResultListener>
      */
     public void requestFailed (final Exception cause)
     {
-        apply(new ObserverOp<ResultListener>() {
-            public boolean apply (ResultListener observer) {
+        apply(new ObserverOp<ResultListener<T>>() {
+            public boolean apply (ResultListener<T> observer) {
                 observer.requestFailed(cause);
                 return true;
             }