proper solution

m-m-m · Oct 4, 2023 · 095c078 · 095c078
1 parent 957fced
commit 095c078
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Showing 5 changed files with 61 additions and 57 deletions.
diff --git a/core/src/main/java/io/github/mmm/event/AbstractEventSender.java b/core/src/main/java/io/github/mmm/event/AbstractEventSender.java
@@ -42,8 +42,8 @@ public boolean removeListener(L listener) {
   }
 
   /**
-   * @return {@code true} if at least one {@link EventListener} is {@link #addListener(EventListener, boolean)
-   *         registered}, {@code false} otherwise.
+   * @return {@code true} if at least one {@link EventListener} is {@link #addListener(EventListener) registered},
+   *         {@code false} otherwise.
    */
   protected boolean hasListeners() {
 

diff --git a/core/src/main/java/io/github/mmm/event/AbstractEventSource.java b/core/src/main/java/io/github/mmm/event/AbstractEventSource.java
@@ -2,8 +2,6 @@
  * http://www.apache.org/licenses/LICENSE-2.0 */
 package io.github.mmm.event;
 
-import io.github.mmm.event.impl.WeakEventListener;
-
 /**
  * Implementation of {@link EventSource}.
  *
@@ -21,58 +19,15 @@ public AbstractEventSource() {
     super();
   }
 
-  /**
-   * @param listener the {@link EventListener} to wrap (potentially).
-   * @param weak - {@code true} to wrap as {@link WeakEventListener}, {@code false} otherwise.
-   * @return the given {@link EventListener} or a {@link WeakEventListener} wrapping it in case {@code weak} is
-   *         {@code true}.
-   * @see EventSource#addListener(EventListener, boolean)
-   */
-  protected final EventListener<E> wrap(EventListener<E> listener, boolean weak) {
-
-    if (weak) {
-      return new WeakEventListener<>(this, listener);
-    }
-    return listener;
-  }
-
-  /**
-   * @param <E> type of the event.
-   * @param listener the {@link EventListener} to unwrap (potentially).
-   * @return the given {@link EventListener} or the unwrapped {@link EventListener} if a {@link WeakEventListener} was
-   *         given.
-   */
-  protected static <E> EventListener<E> unwrap(EventListener<E> listener) {
-
-    if (listener == null) {
-      return null;
-    } else if (listener instanceof WeakEventListener) {
-      return ((WeakEventListener<E>) listener).ref.get();
-    }
-    return listener;
-  }
-
-  /**
-   * @param listener2remove the {@link EventListener} to {@link #removeListener(EventListener) remove}.
-   * @param registeredListener the {@link #addListener(EventListener) registered} {@link EventListener} to match with.
-   * @return {@code true} if the given {@link EventListener}s match, {@code false} otherwise.
-   */
-  protected static boolean matches(EventListener<?> listener2remove, EventListener<?> registeredListener) {
-
-    registeredListener = AbstractEventSource.unwrap(registeredListener);
-    if (listener2remove == registeredListener) {
-      return true;
-    } else if ((registeredListener.isMatchedUsingEquals()) && registeredListener.equals(listener2remove)) {
-      return true;
-    }
-    return false;
-  }
-
-  @SuppressWarnings({ "rawtypes", "unchecked" })
+  @SuppressWarnings("unchecked")
   @Override
   public void addListener(L listener, boolean weak) {
 
-    doAddListener(wrap((EventListener) listener, weak));
+    EventListener<E> l = (EventListener<E>) listener;
+    if (weak) {
+      l = l.weak(this);
+    }
+    doAddListener(l);
   }
 
   /**

diff --git a/core/src/main/java/io/github/mmm/event/EventListener.java b/core/src/main/java/io/github/mmm/event/EventListener.java
@@ -2,6 +2,8 @@
  * http://www.apache.org/licenses/LICENSE-2.0 */
 package io.github.mmm.event;
 
+import io.github.mmm.event.impl.WeakEventListener;
+
 /**
  * Interface for a generic event listener.
  *
@@ -35,4 +37,38 @@ default boolean isMatchedUsingEquals() {
    */
   void onEvent(E event);
 
+  /**
+   * @param source the {@link EventSource}.
+   * @return an instance of {@link EventListener} using a {@link java.lang.ref.WeakReference} so that this original
+   *         {@link EventListener} can be gargabe collected without being
+   *         {@link EventSource#removeListener(EventListener) removed} manually.
+   */
+  default EventListener<E> weak(EventSource<E, ?> source) {
+
+    return new WeakEventListener<>(source, this);
+  }
+
+  /**
+   * @return the raw {@link EventListener} that may be wrapped (e.g. via {@link #weak(EventSource)}).
+   */
+  default EventListener<E> unwrap() {
+
+    return this;
+  }
+
+  /**
+   * @param listener the registered {@link EventListener} to match with.
+   * @return {@code true} if this {@link EventListener} matches the given {@link EventListener}, {@code false}
+   *         otherwise.
+   */
+  default boolean matches(EventListener<?> listener) {
+
+    listener = listener.unwrap();
+    if (this == listener) {
+      return true;
+    } else if ((listener.isMatchedUsingEquals()) && listener.equals(this)) {
+      return true;
+    }
+    return false;
+  }
 }
diff --git a/core/src/main/java/io/github/mmm/event/EventSourceAdapter.java b/core/src/main/java/io/github/mmm/event/EventSourceAdapter.java
@@ -167,7 +167,7 @@ public EventSourceAdapter<E, L> addListener(EventListener<? super E> eventListen
     @Override
     public EventSourceAdapter<E, L> removeListener(EventListener<? super E> eventListener) {
 
-      if (AbstractEventSource.matches(eventListener, this.listener)) {
+      if (eventListener.matches(this.listener)) {
         return EMPTY;
       }
       return null;
@@ -196,7 +196,7 @@ public int getListenerCount() {
     public L getListener(int index) {
 
       if (index == 0) {
-        return (L) AbstractEventSource.unwrap(this.listener);
+        return (L) this.listener.unwrap();
       }
       return null;
     }
@@ -249,7 +249,7 @@ public EventSourceAdapter<E, L> addListener(EventListener<? super E> listener) {
     public EventSourceAdapter<E, L> removeListener(EventListener<? super E> listener) {
 
       for (int i = 0; i < this.listenerCount; i++) {
-        if (AbstractEventSource.matches(listener, this.listeners[i])) {
+        if (listener.matches(this.listeners[i])) {
           if (this.listenerCount == 2) {
             return new Single<>(this.listeners[1 - i]);
           } else {
@@ -307,7 +307,7 @@ public int getListenerCount() {
     public L getListener(int index) {
 
       if ((index >= 0) && (index < this.listenerCount)) {
-        return (L) AbstractEventSource.unwrap(this.listeners[index]);
+        return (L) this.listeners[index].unwrap();
       }
       return null;
     }

diff --git a/core/src/main/java/io/github/mmm/event/impl/WeakEventListener.java b/core/src/main/java/io/github/mmm/event/impl/WeakEventListener.java
@@ -58,6 +58,19 @@ public void onEvent(E event) {
     }
   }
 
+  @Override
+  public EventListener<E> weak(EventSource<E, ?> eventSource) {
+
+    assert (eventSource == this.source);
+    return this;
+  }
+
+  @Override
+  public EventListener<E> unwrap() {
+
+    return this.ref.get();
+  }
+
   /**
    * @param count the current size of listeners. Has to be less or equal to the length of the given {@code listeners}
    *        array.