added PluginBackendListener

scm-plugin-backend/src/main/java/sonia/scm/plugin/AbstractPluginBackend.java

@@ -42,6 +42,9 @@ import sonia.scm.util.Util;
 import java.io.File;
 
 import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Set;
 
 /**
  *
@@ -50,6 +53,30 @@ import java.util.Arrays;
 public abstract class AbstractPluginBackend implements PluginBackend
 {
 
+  /**
+   *   Method description
+   *
+   *
+   *   @param listener
+   */
+  @Override
+  public void addListener(PluginBackendListener listener)
+  {
+    listenerSet.add(listener);
+  }
+
+  /**
+   * Method description
+   *
+   *
+   * @param listeners
+   */
+  @Override
+  public void addListeners(Collection<PluginBackendListener> listeners)
+  {
+    listenerSet.addAll(listeners);
+  }
+
   /**
    * Method description
    *
@@ -79,4 +106,37 @@ public abstract class AbstractPluginBackend implements PluginBackend
       addScannedFiles(Arrays.asList(scannedFiles));
     }
   }
+
+  /**
+   * Method description
+   *
+   *
+   * @param listener
+   */
+  @Override
+  public void removeListener(PluginBackendListener listener)
+  {
+    listenerSet.remove(listener);
+  }
+
+  /**
+   * Method description
+   *
+   *
+   *
+   * @param plugins
+   */
+  protected void fireEvent(Collection<PluginInformation> plugins)
+  {
+    for (PluginBackendListener listener : listenerSet)
+    {
+      listener.addedNewPlugins(plugins);
+    }
+  }
+
+  //~--- fields ---------------------------------------------------------------
+
+  /** Field description */
+  private Set<PluginBackendListener> listenerSet =
+    new HashSet<PluginBackendListener>();
 }