Added ability to dynamically unload plugins.

git-svn-id: http://svn.igniterealtime.org/svn/repos/messenger/trunk@829 b35dd754-fafc-0310-a699-88a17e54d16e

src/java/org/jivesoftware/admin/AdminConsole.java

@@ -24,19 +24,19 @@ import java.io.InputStream;
 import java.net.URL;
 
 /**
- * A model for admin tab and sidebar info. This class loads in xml definitions of the data and
- * produces an in-memory model.<p>
+ * A model for admin tab and sidebar info. This class loads in xml definitions of the
+ * data and produces an in-memory model.<p>
  *
- * This class loads its data from the <tt>admin-sidebar.xml</tt> file which is assumed to be in
- * the main application jar file. In addition, it will load files from
- * <tt>META-INF/admin-sidebar.xml</tt> if they're found. This allows developers to extend the
- * functionality of the admin console to provide more options. See the main
- * <tt>admin-sidebar.xml</tt> file for documentation of its format.<p>
+ * This class loads its data from the <tt>admin-sidebar.xml</tt> file which is assumed
+ * to be in the main application jar file. In addition, it will load files from
+ * <tt>META-INF/admin-sidebar.xml</tt> if they're found. This allows developers to
+ * extend the functionality of the admin console to provide more options. See the main
+ * <tt>admin-sidebar.xml</tt> file for documentation of its format.
  */
 public class AdminConsole {
 
     private static Element coreModel;
-    private static List<Element> overrideModels;
+    private static Map<String,Element> overrideModels;
     private static Element generatedModel;
 
     static {
@@ -44,7 +44,7 @@ public class AdminConsole {
     }
 
     private static void init() {
-        overrideModels = new ArrayList<Element>();
+        overrideModels = new HashMap<String,Element>();
         load();
     }
 
@@ -55,23 +55,35 @@ public class AdminConsole {
     /**
      * Adds XML stream to the tabs/sidebar model.
      *
+     * @param name the name.
      * @param in the XML input stream.
      * @throws Exception if an error occurs when parsing the XML or adding it to the model.
      */
-    public static void addModel(InputStream in) throws Exception {
+    public static void addModel(String name, InputStream in) throws Exception {
         SAXReader saxReader = new SAXReader();
         Document doc = saxReader.read(in);
-        addModel((Element)doc.selectSingleNode("/adminconsole"));
+        addModel(name, (Element)doc.selectSingleNode("/adminconsole"));
     }
 
     /**
      * Adds an &lt;adminconsole&gt; Element to the tabs/sidebar model.
      *
+     * @param name the name.
      * @param element the Element
      * @throws Exception if an error occurs.
      */
-    public static void addModel(Element element) throws Exception {
-        overrideModels.add(element);
+    public static void addModel(String name, Element element) throws Exception {
+        overrideModels.put(name, element);
+        rebuildModel();
+    }
+
+    /**
+     * Removes an &lt;adminconsole&gt; Element from the tabs/sidebar model.
+     *
+     * @param name the name.
+     */
+    public static void removeModel(String name) {
+        overrideModels.remove(name);
         rebuildModel();
     }
 
@@ -190,7 +202,7 @@ public class AdminConsole {
                         url = (URL)e.nextElement();
                         try {
                             in = url.openStream();
-                            addModel(in);
+                            addModel("admin", in);
                         }
                         finally {
                             try { if (in != null) { in.close(); } }
@@ -219,7 +231,7 @@ public class AdminConsole {
         doc.add(generatedModel);
 
         // Add in all overrides.
-        for (Element element : overrideModels) {
+        for (Element element : overrideModels.values()) {
             // See if global settings are overriden.
             Element appName = (Element)element.selectSingleNode("//adminconsole/global/appname");
             if (appName != null) {

src/java/org/jivesoftware/messenger/container/PluginClassLoader.java

@@ -69,7 +69,6 @@ class PluginClassLoader {
             urlArray[i] = (URL)urls.next();
         }
         classLoader = new URLClassLoader(urlArray, findParentClassLoader());
-        Thread.currentThread().setContextClassLoader(classLoader);
     }
 
     /**
@@ -88,6 +87,13 @@ class PluginClassLoader {
         return classLoader.loadClass(name);
     }
 
+    /**
+     * Destroys this class loader.
+     */
+    public void destroy() {
+        classLoader = null;
+    }
+
     /**
      * Locates the best parent class loader based on context.
      *

src/java/org/jivesoftware/messenger/container/PluginManager.java

@@ -27,6 +27,7 @@ import java.util.zip.ZipFile;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * Loads and manages plugins. The <tt>plugins</tt> directory is monitored for any
@@ -50,7 +51,7 @@ public class PluginManager {
      */
     public PluginManager(File pluginDir) {
         this.pluginDirectory = pluginDir;
-        plugins = new HashMap<String,Plugin>();
+        plugins = new ConcurrentHashMap<String,Plugin>();
         classloaders = new HashMap<Plugin,PluginClassLoader>();
     }
 
@@ -75,6 +76,7 @@ public class PluginManager {
             plugin.destroy();
         }
         plugins.clear();
+        classloaders.clear();
     }
 
     /**
@@ -143,7 +145,7 @@ public class PluginManager {
                         Attribute attr = (Attribute)urls.get(i);
                         attr.setValue("plugins/" + pluginDir.getName() + "/" + attr.getValue());
                     }
-                    AdminConsole.addModel(adminElement);
+                    AdminConsole.addModel(pluginDir.getName(), adminElement);
                 }
             }
             else {
@@ -155,6 +157,32 @@ public class PluginManager {
         }
     }
 
+    /**
+     * Unloads a plugin. The {@link Plugin#destroy()} method will be called and then
+     * any resources will be released.
+     *
+     * @param pluginName the name of the plugin to unload.
+     */
+    public void unloadPlugin(String pluginName) {
+        Log.debug("Unloading plugin " + pluginName);
+        Plugin plugin = plugins.get(pluginName);
+        if (plugin == null) {
+            return;
+        }
+        File webXML = new File(pluginDirectory + File.separator + pluginName +
+                File.separator + "web" + File.separator + "web.xml");
+        if (webXML.exists()) {
+            AdminConsole.removeModel(pluginName);
+            PluginServlet.unregisterServlets(webXML);
+        }
+
+        PluginClassLoader classLoader = classloaders.get(plugin);
+        plugin.destroy();
+        classLoader.destroy();
+        plugins.remove(pluginName);
+        classloaders.remove(plugin);
+    }
+
     public Class loadClass(String className, Plugin plugin) throws ClassNotFoundException,
             IllegalAccessException, InstantiationException
     {
@@ -179,45 +207,25 @@ public class PluginManager {
 
                 for (int i=0; i<jars.length; i++) {
                     File jarFile = jars[i];
-                    String jarName = jarFile.getName().substring(
+                    String pluginName = jarFile.getName().substring(
                             0, jarFile.getName().length()-4).toLowerCase();
                     // See if the JAR has already been exploded.
-                    File dir = new File(pluginDirectory, jarName);
+                    File dir = new File(pluginDirectory, pluginName);
                     // If the JAR hasn't been exploded, do so.
                     if (!dir.exists()) {
-                        try {
-                            ZipFile zipFile = new JarFile(jarFile);
-                            // Ensure that this JAR is a plugin.
-                            if (zipFile.getEntry("plugin.xml") == null) {
-                                continue;
-                            }
-                            dir.mkdir();
-                            Log.debug("Extracting plugin: " + jarName);
-                            for (Enumeration e=zipFile.entries(); e.hasMoreElements(); ) {
-                                JarEntry entry = (JarEntry)e.nextElement();
-                                File entryFile = new File(dir, entry.getName());
-                                // Ignore any manifest.mf entries.
-                                if (entry.getName().toLowerCase().endsWith("manifest.mf")) {
-                                    continue;
-                                }
-                                if (!entry.isDirectory()) {
-                                    entryFile.getParentFile().mkdirs();
-                                    FileOutputStream out = new FileOutputStream(entryFile);
-                                    InputStream zin = zipFile.getInputStream(entry);
-                                    byte [] b = new byte[512];
-                                    int len = 0;
-                                    while ( (len=zin.read(b))!= -1 ) {
-                                        out.write(b,0,len);
-                                    }
-                                    out.flush();
-                                    out.close();
-                                    zin.close();
-                                }
-                            }
-                        }
-                        catch (Exception e) {
-                            Log.error(e);
+                        unzipPlugin(pluginName, jarFile, dir);
+                    }
+                    // See if the JAR is newer than the directory. If so, the plugin
+                    // needs to be unloaded and then reloaded.
+                    else if (jarFile.lastModified() > dir.lastModified()) {
+                        unloadPlugin(pluginName);
+                        if (!deleteDir(dir)) {
+                            Log.error("Error unloading plugin " + pluginName + ". " +
+                                    "You must manually delete the plugin directory.");
+                            continue;
                         }
+                        // Now unzip the plugin.
+                        unzipPlugin(pluginName, jarFile, dir);
                     }
                 }
 
@@ -248,10 +256,89 @@ public class PluginManager {
                         loadPlugin(dirFile);
                     }
                 }
+
+                // Finally see if any currently running plugins need to be unloaded
+                // due to its JAR file being deleted (ignore admin plugin).
+                if (plugins.size() > jars.length + 1) {
+                    for (String pluginName : plugins.keySet()) {
+                        if (pluginName.equals("admin")) {
+                            continue;
+                        }
+                        File file = new File(pluginDirectory, pluginName + ".jar");
+                        if (!file.exists()) {
+                            unloadPlugin(pluginName);
+                            if (!deleteDir(new File(pluginDirectory, pluginName))) {
+                                Log.error("Error unloading plugin " + pluginName + ". " +
+                                        "You must manually delete the plugin directory.");
+                                continue;
+                            }
+                        }
+                    }
+                }
             }
             catch (Exception e) {
                 Log.error(e);
             }
         }
+
+        /**
+         * Unzips a plugin from a JAR file into a directory. If the JAR file
+         * isn't a plugin, this method will do nothing.
+         *
+         * @param pluginName the name of the plugin.
+         * @param file the JAR file
+         * @param dir the directory to extract the plugin to. 
+         */
+        private void unzipPlugin(String pluginName, File file, File dir) {
+            try {
+                ZipFile zipFile = new JarFile(file);
+                // Ensure that this JAR is a plugin.
+                if (zipFile.getEntry("plugin.xml") == null) {
+                    return;
+                }
+                dir.mkdir();
+                Log.debug("Extracting plugin: " + pluginName);
+                for (Enumeration e=zipFile.entries(); e.hasMoreElements(); ) {
+                    JarEntry entry = (JarEntry)e.nextElement();
+                    File entryFile = new File(dir, entry.getName());
+                    // Ignore any manifest.mf entries.
+                    if (entry.getName().toLowerCase().endsWith("manifest.mf")) {
+                        continue;
+                    }
+                    if (!entry.isDirectory()) {
+                        entryFile.getParentFile().mkdirs();
+                        FileOutputStream out = new FileOutputStream(entryFile);
+                        InputStream zin = zipFile.getInputStream(entry);
+                        byte [] b = new byte[512];
+                        int len = 0;
+                        while ( (len=zin.read(b))!= -1 ) {
+                            out.write(b,0,len);
+                        }
+                        out.flush();
+                        out.close();
+                        zin.close();
+                    }
+                }
+            }
+            catch (Exception e) {
+                Log.error(e);
+            }
+        }
+
+        /**
+         * Deletes a directory.
+         */
+         public boolean deleteDir(File dir) {
+            if (dir.isDirectory()) {
+                String[] children = dir.list();
+                for (int i=0; i<children.length; i++) {
+                    boolean success = deleteDir(new File(dir, children[i]));
+                    if (!success) {
+                        return false;
+                    }
+                }
+            }
+            return dir.delete();
+        }
     }
 }
\ No newline at end of file

src/java/org/jivesoftware/messenger/container/PluginServlet.java

@@ -97,6 +97,7 @@ public class PluginServlet extends HttpServlet {
     /**
      * Registers all JSP page servlets for a plugin.
      *
+     * @param manager the plugin manager.
      * @param plugin the plugin.
      * @param webXML the web.xml file containing JSP page names to servlet class file
      *      mappings.
@@ -146,6 +147,41 @@ public class PluginServlet extends HttpServlet {
         }
     }
 
+    /**
+     * Unregisters all JSP page servlets for a plugin.
+     *
+     * @param webXML the web.xml file containing JSP page names to servlet class file
+     *      mappings.
+     */
+    public static void unregisterServlets(File webXML) {
+        if (!webXML.exists()) {
+            Log.error("Could not unregister plugin servlets, file " + webXML.getAbsolutePath() +
+                    " does not exist.");
+            return;
+        }
+        // Find the name of the plugin directory given that the webXML file
+        // lives in plugins/[pluginName]/web/web.xml
+        String pluginName = webXML.getParentFile().getParentFile().getName();
+        try {
+            SAXReader saxReader = new SAXReader();
+            Document doc = saxReader.read(webXML);
+            // Find all <servelt-mapping> entries to discover name to URL mapping.
+            List names = doc.selectNodes("//servlet-mapping");
+            for (int i=0; i<names.size(); i++) {
+                Element nameElement = (Element)names.get(i);
+                String url = nameElement.element("url-pattern").getTextTrim();
+                // Destroy the servlet than remove from servlets map.
+                HttpServlet servlet = servlets.get(pluginName + url);
+                servlet.destroy();
+                servlets.remove(pluginName + url);
+                servlet = null;
+            }
+        }
+        catch (Throwable e) {
+            Log.error(e);
+        }
+    }
+
     /**
      * Handles a request for a JSP page. It checks to see if a servlet is mapped
      * for the JSP URL. If one is found, request handling is passed to it. If no