Changeset 8017 in josm for trunk/src/org/openstreetmap/josm/plugins/PluginHandler.java

Timestamp:

2015-02-09T08:43:18+01:00 (9 years ago)

Author:

bastiK

Message:

see #11090 - basic support for plugin loading at runtime.

This is still in testing stage. It will be announced on
the mailing list when plugin authors can start to adapt
their code.

File:

• trunk/src/org/openstreetmap/josm/plugins/PluginHandler.java (modified) (6 diffs)

trunk/src/org/openstreetmap/josm/plugins/PluginHandler.java

@@ -187 +187 @@
 
     /**
+     * ClassLoader that makes the addURL method of URLClassLoader public.
+     *
+     * Like URLClassLoader, but allows to add more URLs after construction.
+     */
+    public static class DynamicURLClassLoader extends URLClassLoader {
+
+        public DynamicURLClassLoader(URL[] urls, ClassLoader parent) {
+            super(urls, parent);
+        }
+
+        @Override
+        public void addURL(URL url) {
+            super.addURL(url);
+        }
+    }
+
+    /**
      * List of unmaintained plugins. Not really up-to-date as the vast majority of plugins are not really maintained after a few months, sadly...
      */
@@ -200 +217 @@
      */
     public static final Collection<PluginProxy> pluginList = new LinkedList<>();
+
+    /**
+     * Global plugin ClassLoader.
+     */
+    private static DynamicURLClassLoader pluginClassLoader;
 
     /**
@@ -536 +558 @@
 
     /**
-     * Creates a class loader for loading plugin code.
-     *
-     * @param plugins the collection of plugins which are going to be loaded with this
-     * class loader
+     * Get the class loader for loading plugin code.
+     *
      * @return the class loader
      */
-    public static ClassLoader createClassLoader(Collection<PluginInformation> plugins) {
+    public static DynamicURLClassLoader getPluginClassLoader() {
+        if (pluginClassLoader == null) {
+            pluginClassLoader = AccessController.doPrivileged(new PrivilegedAction<DynamicURLClassLoader>() {
+                public DynamicURLClassLoader run() {
+                    return new DynamicURLClassLoader(new URL[0], Main.class.getClassLoader());
+                }
+            });
+            sources.add(0, pluginClassLoader);
+        }
+        return pluginClassLoader;
+    }
+
+    /**
+     * Add more plugins to the plugin class loader.
+     *
+     * @param plugins the plugins that should be handled by the plugin class loader
+     */
+    public static void extendPluginClassLoader(Collection<PluginInformation> plugins) {
         // iterate all plugins and collect all libraries of all plugins:
-        List<URL> allPluginLibraries = new LinkedList<>();
         File pluginDir = Main.pref.getPluginsDirectory();
-
-        // Add all plugins already loaded (to include early plugins in the classloader, allowing late plugins to rely on early ones)
-        Collection<PluginInformation> allPlugins = new HashSet<>(plugins);
-        for (PluginProxy proxy : pluginList) {
-            allPlugins.add(proxy.getPluginInformation());
-        }
-
-        for (PluginInformation info : allPlugins) {
+        DynamicURLClassLoader cl = getPluginClassLoader();
+
+        for (PluginInformation info : plugins) {
             if (info.libraries == null) {
                 continue;
             }
-            allPluginLibraries.addAll(info.libraries);
+            for (URL libUrl : info.libraries) {
+                cl.addURL(libUrl);
+            }
             File pluginJar = new File(pluginDir, info.name + ".jar");
             I18n.addTexts(pluginJar);
             URL pluginJarUrl = Utils.fileToURL(pluginJar);
-            allPluginLibraries.add(pluginJarUrl);
-        }
-
-        // create a classloader for all plugins:
-        final URL[] jarUrls = allPluginLibraries.toArray(new URL[allPluginLibraries.size()]);
-        return AccessController.doPrivileged(new PrivilegedAction<ClassLoader>() {
-            public ClassLoader run() {
-                return new URLClassLoader(jarUrls, Main.class.getClassLoader());
-            }
-      });
+            cl.addURL(pluginJarUrl);
+        }
     }
 
@@ -614 +639 @@
      * @param monitor the progress monitor. Defaults to {@link NullProgressMonitor#INSTANCE} if null.
      */
-    public static void loadPlugins(Component parent,Collection<PluginInformation> plugins, ProgressMonitor monitor) {
+    public static void loadPlugins(Component parent, Collection<PluginInformation> plugins, ProgressMonitor monitor) {
         if (monitor == null) {
             monitor = NullProgressMonitor.INSTANCE;
@@ -644 +669 @@
                 return;
 
-            ClassLoader pluginClassLoader = createClassLoader(toLoad);
-            sources.add(0, pluginClassLoader);
+            extendPluginClassLoader(toLoad);
             monitor.setTicksCount(toLoad.size());
             for (PluginInformation info : toLoad) {
                 monitor.setExtraText(tr("Loading plugin ''{0}''...", info.name));
-                loadPlugin(parent, info, pluginClassLoader);
+                loadPlugin(parent, info, getPluginClassLoader());
                 monitor.worked(1);
             }
@@ -1045 +1069 @@
      * If {@code dowarn} is true, this methods emits warning messages on the console if a downloaded
      * but not yet installed plugin .jar can't be be installed. If {@code dowarn} is false, the
-     * installation of the respective plugin is sillently skipped.
+     * installation of the respective plugin is silently skipped.
      *
      * @param dowarn if true, warning messages are displayed; false otherwise