From 4fefdcf76cb7b9c5df414fc870ad2bfebb96e5bb Mon Sep 17 00:00:00 2001
From: James Moger <james.moger@gitblit.com>
Date: Wed, 2 Apr 2014 20:10:26 -0400
Subject: [PATCH] Add method to unload a plugin and it's dependencies

---
 .../fortsoft/pf4j/DefaultPluginManager.java   | 39 +++++++++++++++++++
 .../java/ro/fortsoft/pf4j/PluginManager.java  |  8 ++++
 .../pf4j/util/CompoundClassLoader.java        | 20 ++++++----
 3 files changed, 59 insertions(+), 8 deletions(-)

diff --git a/pf4j/src/main/java/ro/fortsoft/pf4j/DefaultPluginManager.java b/pf4j/src/main/java/ro/fortsoft/pf4j/DefaultPluginManager.java
index 1680a5a..1bca676 100644
--- a/pf4j/src/main/java/ro/fortsoft/pf4j/DefaultPluginManager.java
+++ b/pf4j/src/main/java/ro/fortsoft/pf4j/DefaultPluginManager.java
@@ -294,6 +294,45 @@ public class DefaultPluginManager implements PluginManager {
 		}
     }
 
+    @Override
+    public boolean unloadPlugin(String pluginId) {
+    	try {
+    		PluginState state = stopPlugin(pluginId);
+    		if (!PluginState.STOPPED.equals(state)) {
+    			return false;
+    		}
+
+    		PluginWrapper pluginWrapper = plugins.get(pluginId);
+    		PluginDescriptor descriptor = pluginWrapper.getDescriptor();
+    		List<PluginDependency> dependencies = descriptor.getDependencies();
+    		for (PluginDependency dependency : dependencies) {
+    			if (!unloadPlugin(dependency.getPluginId())) {
+    				return false;
+    			}
+    		}
+
+    		// remove the plugin
+    		plugins.remove(pluginId);
+    		resolvedPlugins.remove(pluginWrapper);
+    		pathToIdMap.remove(pluginWrapper.getPluginPath());
+
+    		// remove the classloader
+    		if (pluginClassLoaders.containsKey(pluginId)) {
+    			PluginClassLoader classLoader = pluginClassLoaders.remove(pluginId);
+    			compoundClassLoader.removeLoader(classLoader);
+    			try {
+    				classLoader.close();
+    			} catch (IOException e) {
+    				log.error(e.getMessage(), e);
+    			}
+    		}
+    		return true;
+    	} catch (IllegalArgumentException e) {
+    		// ignore not found exceptions because this method is recursive
+    	}
+    	return false;
+    }
+
     /**
      * Get plugin class loader for this path.
      */
diff --git a/pf4j/src/main/java/ro/fortsoft/pf4j/PluginManager.java b/pf4j/src/main/java/ro/fortsoft/pf4j/PluginManager.java
index e183a95..6ffe4cf 100644
--- a/pf4j/src/main/java/ro/fortsoft/pf4j/PluginManager.java
+++ b/pf4j/src/main/java/ro/fortsoft/pf4j/PluginManager.java
@@ -71,6 +71,14 @@ public interface PluginManager {
      */
     public PluginState stopPlugin(String pluginId);
 
+    /**
+     * Unload a plugin.
+     *
+     * @param pluginId
+     * @return true if the plugin was unloaded
+     */
+    public boolean unloadPlugin(String pluginId);
+
 	public PluginClassLoader getPluginClassLoader(String pluginId);
 
 	public <T> List<T> getExtensions(Class<T> type);
diff --git a/pf4j/src/main/java/ro/fortsoft/pf4j/util/CompoundClassLoader.java b/pf4j/src/main/java/ro/fortsoft/pf4j/util/CompoundClassLoader.java
index f5c5df4..426b2a3 100644
--- a/pf4j/src/main/java/ro/fortsoft/pf4j/util/CompoundClassLoader.java
+++ b/pf4j/src/main/java/ro/fortsoft/pf4j/util/CompoundClassLoader.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.
@@ -23,7 +23,7 @@ import java.util.Set;
 
 /**
  * A class loader that has multiple loaders and uses them for loading classes and resources.
- * 
+ *
  * @author Decebal Suiu
  */
 public class CompoundClassLoader extends ClassLoader {
@@ -34,6 +34,10 @@ public class CompoundClassLoader extends ClassLoader {
 		loaders.add(loader);
 	}
 
+	public void removeLoader(ClassLoader loader) {
+		loaders.remove(loader);
+	}
+
 	@Override
 	public Class<?> findClass(String name) throws ClassNotFoundException {
 		for (ClassLoader loader : loaders) {
@@ -43,7 +47,7 @@ public class CompoundClassLoader extends ClassLoader {
 				// try next
 			}
 		}
-		
+
 		throw new ClassNotFoundException(name);
 	}
 
@@ -55,7 +59,7 @@ public class CompoundClassLoader extends ClassLoader {
 				return url;
 			}
 		}
-		
+
 		return null;
 	}
 
@@ -65,8 +69,8 @@ public class CompoundClassLoader extends ClassLoader {
 		for (ClassLoader loader : loaders) {
 			resources.addAll(Collections.list(loader.getResources(name)));
 		}
-		
+
 		return Collections.enumeration(resources);
 	}
-	
+
 }