add listeners to plugin state changes

8 files changed, 186 insertions, 53 deletions

diff --git a/pf4j/src/main/java/ro/fortsoft/pf4j/DefaultExtensionFinder.java b/pf4j/src/main/java/ro/fortsoft/pf4j/DefaultExtensionFinder.java
index c31f5d3..295d5c8 100644
--- a/pf4j/src/main/java/ro/fortsoft/pf4j/DefaultExtensionFinder.java
+++ b/pf4j/src/main/java/ro/fortsoft/pf4j/DefaultExtensionFinder.java
@@ -28,7 +28,7 @@ import org.slf4j.LoggerFactory;
  *
  * @author Decebal Suiu
  */
-public class DefaultExtensionFinder implements ExtensionFinder {
+public class DefaultExtensionFinder implements ExtensionFinder, PluginStateListener {
 
 	private static final Logger log = LoggerFactory.getLogger(DefaultExtensionFinder.class);
 
@@ -95,8 +95,8 @@ public class DefaultExtensionFinder implements ExtensionFinder {
         return entries.get(pluginId);
     }
 
-    @Override
-    public void reset() {
+    public void pluginStateChanged(PluginStateEvent event) {
+        // TODO optimize (do only for some transitions)
         // clear cache
         entries = null;
     }
diff --git a/pf4j/src/main/java/ro/fortsoft/pf4j/DefaultPluginManager.java b/pf4j/src/main/java/ro/fortsoft/pf4j/DefaultPluginManager.java
index cf02045..47dce71 100644
--- a/pf4j/src/main/java/ro/fortsoft/pf4j/DefaultPluginManager.java
+++ b/pf4j/src/main/java/ro/fortsoft/pf4j/DefaultPluginManager.java
@@ -78,6 +78,11 @@ public class DefaultPluginManager implements PluginManager {
     private List<String> disabledPlugins;
 
     /**
+     * The registered {@link PluginStateListener}s.
+     */
+    private List<PluginStateListener> pluginStateListeners;
+
+    /**
      * Cache value for the runtime mode. No need to re-read it because it wont change at
 	 * runtime.
      */
@@ -143,7 +148,7 @@ public class DefaultPluginManager implements PluginManager {
 
 	@Override
 	public String loadPlugin(File pluginArchiveFile) {
-		if (pluginArchiveFile == null || !pluginArchiveFile.exists()) {
+		if ((pluginArchiveFile == null) || !pluginArchiveFile.exists()) {
 			throw new IllegalArgumentException(String.format("Specified plugin %s does not exist!", pluginArchiveFile));
 		}
 
@@ -153,7 +158,7 @@ public class DefaultPluginManager implements PluginManager {
 		} catch (IOException e) {
 			log.error(e.getMessage(), e);
 		}
-		if (pluginDirectory == null || !pluginDirectory.exists()) {
+		if ((pluginDirectory == null) || !pluginDirectory.exists()) {
 			throw new IllegalArgumentException(String.format("Failed to expand %s", pluginArchiveFile));
 		}
 
@@ -162,7 +167,9 @@ public class DefaultPluginManager implements PluginManager {
 			// TODO uninstalled plugin dependencies?
         	unresolvedPlugins.remove(pluginWrapper);
         	resolvedPlugins.add(pluginWrapper);
-        	extensionFinder.reset();
+
+            firePluginStateEvent(new PluginStateEvent(this, pluginWrapper, null));
+
 			return pluginWrapper.getDescriptor().getPluginId();
 		} catch (PluginException e) {
 			log.error(e.getMessage(), e);
@@ -185,6 +192,8 @@ public class DefaultPluginManager implements PluginManager {
                     pluginWrapper.getPlugin().start();
                     pluginWrapper.setPluginState(PluginState.STARTED);
                     startedPlugins.add(pluginWrapper);
+
+                    firePluginStateEvent(new PluginStateEvent(this, pluginWrapper, pluginState));
                 } catch (PluginException e) {
                     log.error(e.getMessage(), e);
                 }
@@ -201,17 +210,18 @@ public class DefaultPluginManager implements PluginManager {
     		throw new IllegalArgumentException(String.format("Unknown pluginId %s", pluginId));
     	}
 
-    	PluginWrapper pluginWrapper = plugins.get(pluginId);
+    	PluginWrapper pluginWrapper = getPlugin(pluginId);
     	PluginDescriptor pluginDescriptor = pluginWrapper.getDescriptor();
-    	if (PluginState.STARTED == pluginWrapper.getPluginState()) {
+        PluginState pluginState = pluginWrapper.getPluginState();
+    	if (PluginState.STARTED == pluginState) {
     		log.debug("Already started plugin '{}:{}'", pluginDescriptor.getPluginId(), pluginDescriptor.getVersion());
     		return PluginState.STARTED;
     	}
 
-        if (PluginState.DISABLED == pluginWrapper.getPluginState()) {
+        if (PluginState.DISABLED == pluginState) {
             // automatically enable plugin on manual plugin start
             if (!enablePlugin(pluginId)) {
-                return pluginWrapper.getPluginState();
+                return pluginState;
             }
         }
 
@@ -224,7 +234,9 @@ public class DefaultPluginManager implements PluginManager {
     		pluginWrapper.getPlugin().start();
     		pluginWrapper.setPluginState(PluginState.STARTED);
     		startedPlugins.add(pluginWrapper);
-    	} catch (PluginException e) {
+
+            firePluginStateEvent(new PluginStateEvent(this, pluginWrapper, pluginState));
+        } catch (PluginException e) {
     		log.error(e.getMessage(), e);
     	}
 
@@ -241,13 +253,16 @@ public class DefaultPluginManager implements PluginManager {
     	Iterator<PluginWrapper> itr = startedPlugins.iterator();
         while (itr.hasNext()) {
         	PluginWrapper pluginWrapper = itr.next();
-            if (PluginState.STARTED == pluginWrapper.getPluginState()) {
+            PluginState pluginState = pluginWrapper.getPluginState();
+            if (PluginState.STARTED == pluginState) {
                 try {
                     PluginDescriptor pluginDescriptor = pluginWrapper.getDescriptor();
                     log.info("Stop plugin '{}:{}'", pluginDescriptor.getPluginId(), pluginDescriptor.getVersion());
                     pluginWrapper.getPlugin().stop();
                     pluginWrapper.setPluginState(PluginState.STOPPED);
                     itr.remove();
+
+                    firePluginStateEvent(new PluginStateEvent(this, pluginWrapper, pluginState));
                 } catch (PluginException e) {
                     log.error(e.getMessage(), e);
                 }
@@ -264,17 +279,18 @@ public class DefaultPluginManager implements PluginManager {
     		throw new IllegalArgumentException(String.format("Unknown pluginId %s", pluginId));
     	}
 
-    	PluginWrapper pluginWrapper = plugins.get(pluginId);
+    	PluginWrapper pluginWrapper = getPlugin(pluginId);
     	PluginDescriptor pluginDescriptor = pluginWrapper.getDescriptor();
-    	if (PluginState.STOPPED == pluginWrapper.getPluginState()) {
+        PluginState pluginState = pluginWrapper.getPluginState();
+    	if (PluginState.STOPPED == pluginState) {
     		log.debug("Already stopped plugin '{}:{}'", pluginDescriptor.getPluginId(), pluginDescriptor.getVersion());
     		return PluginState.STOPPED;
     	}
 
         // test for disabled plugin
-        if (PluginState.DISABLED == pluginWrapper.getPluginState()) {
+        if (PluginState.DISABLED == pluginState) {
             // do nothing
-            return pluginWrapper.getPluginState();
+            return pluginState;
         }
 
     	for (PluginDependency dependency : pluginDescriptor.getDependencies()) {
@@ -286,6 +302,8 @@ public class DefaultPluginManager implements PluginManager {
     		pluginWrapper.getPlugin().stop();
     		pluginWrapper.setPluginState(PluginState.STOPPED);
     		startedPlugins.remove(pluginWrapper);
+
+            firePluginStateEvent(new PluginStateEvent(this, pluginWrapper, pluginState));
     	} catch (PluginException e) {
     		log.error(e.getMessage(), e);
     	}
@@ -353,12 +371,12 @@ public class DefaultPluginManager implements PluginManager {
     @Override
     public boolean unloadPlugin(String pluginId) {
     	try {
-    		PluginState state = stopPlugin(pluginId);
-    		if (PluginState.STOPPED != state) {
+    		PluginState pluginState = stopPlugin(pluginId);
+    		if (PluginState.STOPPED != pluginState) {
     			return false;
     		}
 
-    		PluginWrapper pluginWrapper = plugins.get(pluginId);
+    		PluginWrapper pluginWrapper = getPlugin(pluginId);
     		PluginDescriptor descriptor = pluginWrapper.getDescriptor();
     		List<PluginDependency> dependencies = descriptor.getDependencies();
     		for (PluginDependency dependency : dependencies) {
@@ -371,7 +389,8 @@ public class DefaultPluginManager implements PluginManager {
     		plugins.remove(pluginId);
     		resolvedPlugins.remove(pluginWrapper);
     		pathToIdMap.remove(pluginWrapper.getPluginPath());
-    		extensionFinder.reset();
+
+            firePluginStateEvent(new PluginStateEvent(this, pluginWrapper, pluginState));
 
     		// remove the classloader
     		if (pluginClassLoaders.containsKey(pluginId)) {
@@ -398,17 +417,18 @@ public class DefaultPluginManager implements PluginManager {
         }
 
 
-        PluginWrapper pluginWrapper = plugins.get(pluginId);
+        PluginWrapper pluginWrapper = getPlugin(pluginId);
         PluginDescriptor pluginDescriptor = pluginWrapper.getDescriptor();
-
-        if (PluginState.DISABLED == getPlugin(pluginId).getPluginState()) {
+        PluginState pluginState = pluginWrapper.getPluginState();
+        if (PluginState.DISABLED == pluginState) {
         	log.debug("Already disabled plugin '{}:{}'", pluginDescriptor.getPluginId(), pluginDescriptor.getVersion());
            	return true;
         }
 
         if (PluginState.STOPPED == stopPlugin(pluginId)) {
-            getPlugin(pluginId).setPluginState(PluginState.DISABLED);
-            extensionFinder.reset();
+            pluginWrapper.setPluginState(PluginState.DISABLED);
+
+            firePluginStateEvent(new PluginStateEvent(this, pluginWrapper, PluginState.STOPPED));
 
             if (disabledPlugins.add(pluginId)) {
                 try {
@@ -432,10 +452,10 @@ public class DefaultPluginManager implements PluginManager {
             throw new IllegalArgumentException(String.format("Unknown pluginId %s", pluginId));
         }
 
-        PluginWrapper pluginWrapper = plugins.get(pluginId);
+        PluginWrapper pluginWrapper = getPlugin(pluginId);
         PluginDescriptor pluginDescriptor = pluginWrapper.getDescriptor();
-
-        if (PluginState.DISABLED != getPlugin(pluginId).getPluginState()) {
+        PluginState pluginState = pluginWrapper.getPluginState();
+        if (PluginState.DISABLED != pluginState) {
             log.debug("Plugin plugin '{}:{}' is not disabled", pluginDescriptor.getPluginId(), pluginDescriptor.getVersion());
             return true;
         }
@@ -449,8 +469,9 @@ public class DefaultPluginManager implements PluginManager {
             return false;
         }
 
-        getPlugin(pluginId).setPluginState(PluginState.CREATED);
-        extensionFinder.reset();
+        pluginWrapper.setPluginState(PluginState.CREATED);
+
+        firePluginStateEvent(new PluginStateEvent(this, pluginWrapper, pluginState));
 
         log.info("Enabled plugin '{}:{}'", pluginDescriptor.getPluginId(), pluginDescriptor.getVersion());
 
@@ -462,10 +483,10 @@ public class DefaultPluginManager implements PluginManager {
     	if (!plugins.containsKey(pluginId)) {
     		throw new IllegalArgumentException(String.format("Unknown pluginId %s", pluginId));
     	}
-		PluginWrapper pw = getPlugin(pluginId);
-		PluginState state = stopPlugin(pluginId);
 
-		if (PluginState.STOPPED != state) {
+		PluginWrapper pluginWrapper = getPlugin(pluginId);
+		PluginState pluginState = stopPlugin(pluginId);
+		if (PluginState.STOPPED != pluginState) {
 			log.error("Failed to stop plugin {} on delete", pluginId);
 			return false;
 		}
@@ -475,14 +496,14 @@ public class DefaultPluginManager implements PluginManager {
 			return false;
 		}
 
-		File pluginFolder = new File(pluginsDirectory, pw.getPluginPath());
+		File pluginFolder = new File(pluginsDirectory, pluginWrapper.getPluginPath());
 		File pluginZip = null;
 
 		FileFilter zipFilter = new ZipFileFilter();
         File[] zipFiles = pluginsDirectory.listFiles(zipFilter);
         if (zipFiles != null) {
         	// strip prepended / from the plugin path
-        	String dirName = pw.getPluginPath().substring(1);
+        	String dirName = pluginWrapper.getPluginPath().substring(1);
         	// find the zip file that matches the plugin path
         	for (File zipFile : zipFiles) {
         		String name = zipFile.getName().substring(0, zipFile.getName().lastIndexOf('.'));
@@ -499,6 +520,7 @@ public class DefaultPluginManager implements PluginManager {
 		if (pluginZip != null && pluginZip.exists()) {
 			FileUtils.delete(pluginZip);
 		}
+
 		return true;
 	}
 
@@ -551,10 +573,21 @@ public class DefaultPluginManager implements PluginManager {
             }
         }
         log.warn("Failed to find the plugin for {}", clazz);
+
         return null;
     }
 
-	/**
+    @Override
+    public synchronized void addPluginStateListener(PluginStateListener listener) {
+        pluginStateListeners.add(listener);
+    }
+
+    @Override
+    public synchronized void removePluginStateListener(PluginStateListener listener) {
+        pluginStateListeners.remove(listener);
+    }
+
+    /**
 	 * Add the possibility to override the PluginDescriptorFinder.
 	 * By default if getRuntimeMode() returns RuntimeMode.DEVELOPMENT than a
 	 * PropertiesPluginDescriptorFinder is returned else this method returns
@@ -572,7 +605,10 @@ public class DefaultPluginManager implements PluginManager {
      * Add the possibility to override the ExtensionFinder.
      */
     protected ExtensionFinder createExtensionFinder() {
-    	return new DefaultExtensionFinder(this);
+    	DefaultExtensionFinder extensionFinder = new DefaultExtensionFinder(this);
+        addPluginStateListener(extensionFinder);
+
+        return extensionFinder;
     }
 
     /**
@@ -632,6 +668,8 @@ public class DefaultPluginManager implements PluginManager {
         startedPlugins = new ArrayList<PluginWrapper>();
         disabledPlugins = new ArrayList<String>();
 
+        pluginStateListeners = new ArrayList<PluginStateListener>();
+
         pluginClasspath = createPluginClasspath();
         pluginDescriptorFinder = createPluginDescriptorFinder();
         extensionFinder = createExtensionFinder();
@@ -739,4 +777,11 @@ public class DefaultPluginManager implements PluginManager {
         }
 	}
 
+    private synchronized void firePluginStateEvent(PluginStateEvent event) {
+        for (PluginStateListener listener : pluginStateListeners) {
+            log.debug("Fire '{}' to '{}'", event, listener);
+            listener.pluginStateChanged(event);
+        }
+    }
+
 }
diff --git a/pf4j/src/main/java/ro/fortsoft/pf4j/ExtensionFinder.java b/pf4j/src/main/java/ro/fortsoft/pf4j/ExtensionFinder.java
index c518566..7236b49 100644
--- a/pf4j/src/main/java/ro/fortsoft/pf4j/ExtensionFinder.java
+++ b/pf4j/src/main/java/ro/fortsoft/pf4j/ExtensionFinder.java
@@ -30,6 +30,4 @@ public interface ExtensionFinder {
      */
     public Set<String> findClassNames(String pluginId);
 
-    public void reset();
-
 }
diff --git a/pf4j/src/main/java/ro/fortsoft/pf4j/PluginLoader.java b/pf4j/src/main/java/ro/fortsoft/pf4j/PluginLoader.java
index 8bd2daa..03e7683 100644
--- a/pf4j/src/main/java/ro/fortsoft/pf4j/PluginLoader.java
+++ b/pf4j/src/main/java/ro/fortsoft/pf4j/PluginLoader.java
@@ -1,11 +1,11 @@
 /*
  * Copyright 2012 Decebal Suiu
- * 
+ *
  * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this work except in compliance with
  * the License. You may obtain a copy of the License in the LICENSE file, or at:
- * 
+ *
  * http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
  * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
  * specific language governing permissions and limitations under the License.
@@ -46,10 +46,11 @@ class PluginLoader {
 
     public PluginLoader(PluginManager pluginManager, PluginDescriptor pluginDescriptor, File pluginRepository, PluginClasspath pluginClasspath) {
         this.pluginRepository = pluginRepository;
-        this.pluginClasspath = pluginClasspath; 
-        ClassLoader parent = getClass().getClassLoader(); 
-        pluginClassLoader = new PluginClassLoader(pluginManager, pluginDescriptor, parent);        
-        log.debug("Created class loader {}", pluginClassLoader);
+        this.pluginClasspath = pluginClasspath;
+
+        ClassLoader parent = getClass().getClassLoader();
+        pluginClassLoader = new PluginClassLoader(pluginManager, pluginDescriptor, parent);
+        log.debug("Created class loader '{}'", pluginClassLoader);
     }
 
     public File getPluginRepository() {
@@ -70,15 +71,15 @@ class PluginLoader {
 
     private boolean loadClasses() {
     	List<String> classesDirectories = pluginClasspath.getClassesDirectories();
-    	
+
     	// add each classes directory to plugin class loader
     	for (String classesDirectory : classesDirectories) {
 	        // make 'classesDirectory' absolute
 	        File file = new File(pluginRepository, classesDirectory).getAbsoluteFile();
-	
+
 	        if (file.exists() && file.isDirectory()) {
 	            log.debug("Found '{}' directory", file.getPath());
-	
+
 	            try {
 	                pluginClassLoader.addURL(file.toURI().toURL());
 	                log.debug("Added '{}' to the class loader path", file);
@@ -98,12 +99,12 @@ class PluginLoader {
      */
     private boolean loadJars() {
     	List<String> libDirectories = pluginClasspath.getLibDirectories();
-    	
+
     	// add each jars directory to plugin class loader
     	for (String libDirectory : libDirectories) {
 	        // make 'libDirectory' absolute
 	        File file = new File(pluginRepository, libDirectory).getAbsoluteFile();
-	
+
 	        // collect all jars from current lib directory in jars variable
 	        Vector<File> jars = new Vector<File>();
 	        getJars(jars, file);
diff --git a/pf4j/src/main/java/ro/fortsoft/pf4j/PluginManager.java b/pf4j/src/main/java/ro/fortsoft/pf4j/PluginManager.java
index f656313..daf6fbf 100644
--- a/pf4j/src/main/java/ro/fortsoft/pf4j/PluginManager.java
+++ b/pf4j/src/main/java/ro/fortsoft/pf4j/PluginManager.java
@@ -137,4 +137,8 @@ public interface PluginManager {
 	 */
 	public RuntimeMode getRuntimeMode();
 
+    public void addPluginStateListener(PluginStateListener listener);
+
+    public void removePluginStateListener(PluginStateListener listener);
+
 }
diff --git a/pf4j/src/main/java/ro/fortsoft/pf4j/PluginStateEvent.java b/pf4j/src/main/java/ro/fortsoft/pf4j/PluginStateEvent.java
new file mode 100644
index 0000000..bea202e
--- /dev/null
+++ b/pf4j/src/main/java/ro/fortsoft/pf4j/PluginStateEvent.java
@@ -0,0 +1,57 @@
+/*
+ * Copyright 2014 Decebal Suiu
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this work except in compliance with
+ * the License. You may obtain a copy of the License in the LICENSE file, or at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+ * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations under the License.
+ */
+package ro.fortsoft.pf4j;
+
+import java.util.EventObject;
+
+/**
+ * @author Decebal Suiu
+ */
+public class PluginStateEvent extends EventObject {
+
+    private PluginWrapper plugin;
+    private PluginState oldState;
+
+    public PluginStateEvent(PluginManager source, PluginWrapper plugin, PluginState oldState) {
+        super(source);
+
+        this.plugin = plugin;
+        this.oldState = oldState;
+    }
+
+    @Override
+    public PluginManager getSource() {
+        return (PluginManager) super.getSource();
+    }
+
+    public PluginWrapper getPlugin() {
+        return plugin;
+    }
+
+    public PluginState getPluginState() {
+        return plugin.getPluginState();
+    }
+
+    public PluginState getOldState() {
+        return oldState;
+    }
+
+    @Override
+    public String toString() {
+        return "PluginStateEvent [plugin=" + plugin.getPluginId() +
+                ", newState=" + getPluginState() +
+                ", oldState=" + oldState +
+                ']';
+    }
+
+}
diff --git a/pf4j/src/main/java/ro/fortsoft/pf4j/PluginStateListener.java b/pf4j/src/main/java/ro/fortsoft/pf4j/PluginStateListener.java
new file mode 100644
index 0000000..4af2e91
--- /dev/null
+++ b/pf4j/src/main/java/ro/fortsoft/pf4j/PluginStateListener.java
@@ -0,0 +1,29 @@
+/*
+ * Copyright 2014 Decebal Suiu
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this work except in compliance with
+ * the License. You may obtain a copy of the License in the LICENSE file, or at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+ * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations under the License.
+ */
+package ro.fortsoft.pf4j;
+
+import java.util.EventListener;
+
+/**
+ * PluginStateListener defines the interface for an object that listens to plugin state changes.
+ *
+ * @author Decebal Suiu
+ */
+public interface PluginStateListener extends EventListener {
+
+    /**
+     * Invoked when a plugin's state (for example DISABLED, STARTED) is changed.
+     */
+    public void pluginStateChanged(PluginStateEvent event);
+
+}
diff --git a/pf4j/src/main/java/ro/fortsoft/pf4j/PluginWrapper.java b/pf4j/src/main/java/ro/fortsoft/pf4j/PluginWrapper.java
index b2ab37d..da9908a 100644
--- a/pf4j/src/main/java/ro/fortsoft/pf4j/PluginWrapper.java
+++ b/pf4j/src/main/java/ro/fortsoft/pf4j/PluginWrapper.java
@@ -119,8 +119,7 @@ public class PluginWrapper {
 
 	@Override
 	public String toString() {
-		return "PluginWrapper [descriptor=" + descriptor + ", pluginPath="
-				+ pluginPath + "]";
+		return "PluginWrapper [descriptor=" + descriptor + ", pluginPath=" + pluginPath + "]";
 	}
 
 	void setPluginState(PluginState pluginState) {