/**
* This will create a {@link PluginEnvironment} for the plugin at the given URL. The plugin's
* descriptor is parsed. Once this method returns, the plugin's components are ready to be created
* and used.
*
* @param pluginUrl the new plugin's jar location
* @param classLoader the new plugin's classloader
* @param pluginDescriptor the already parsed plugin descriptor for this plugin
* @throws PluginContainerException if the plugin fails to load
*/
private void loadPlugin(URL pluginUrl, ClassLoader classLoader, PluginDescriptor pluginDescriptor)
throws PluginContainerException {
if (log.isDebugEnabled()) {
log.debug("Loading plugin from [" + pluginUrl + "] in classloader [" + classLoader + "]...");
}
PluginDescriptorLoader pluginDescriptorLoader =
new PluginDescriptorLoader(pluginUrl, classLoader);
PluginEnvironment pluginEnvironment =
new PluginEnvironment(pluginDescriptor.getName(), pluginDescriptorLoader);
String pluginName = pluginEnvironment.getPluginName();
// tell the plugin we have loaded it
PluginLifecycleListener overseer =
getPluginLifecycleListener(pluginName, pluginEnvironment, pluginDescriptor);
if (overseer != null) {
PluginContext context = createPluginContext(pluginName);
ClassLoader originalContextClassLoader = Thread.currentThread().getContextClassLoader();
try {
Thread.currentThread().setContextClassLoader(classLoader);
overseer.initialize(context);
} catch (Throwable t) {
throw new PluginContainerException(
"Plugin Lifecycle Listener failed to initialize plugin", t);
} finally {
Thread.currentThread().setContextClassLoader(originalContextClassLoader);
}
}
// everything is loaded and initialized
this.loadedPluginEnvironments.put(pluginName, pluginEnvironment);
this.metadataManager.loadPlugin(pluginDescriptor);
pluginLifecycleListenerMgr.setListener(pluginDescriptor.getName(), overseer);
updateLoadedPlugins.execute(pluginDescriptor, pluginUrl);
}
/**
* Finds all plugins using the plugin finder defined in the <code>pluginContainerConfiguration
* </code> and {@link #loadPlugin(java.net.URL, ClassLoader,
* org.rhq.core.clientapi.descriptor.plugin.PluginDescriptor) loads} each plugin found.
*/
public PluginManager(
PluginContainerConfiguration pluginContainerConfiguration,
PluginLifecycleListenerManager pluginLifecycleListenerManager) {
if (pluginContainerConfiguration == null) {
throw new NullPointerException("pluginContainerConfiguration is null");
}
if (pluginLifecycleListenerManager == null) {
throw new NullPointerException("pluginLifecycleListenerManager is null");
}
this.pluginContainerConfiguration = pluginContainerConfiguration;
this.pluginLifecycleListenerMgr = pluginLifecycleListenerManager;
loadedPluginEnvironments = new HashMap<String, PluginEnvironment>();
loadedPlugins = new ArrayList<Plugin>();
metadataManager = new PluginMetadataManager();
metadataManager.setDisabledResourceTypes(
pluginContainerConfiguration.getDisabledResourceTypes());
updateLoadedPlugins =
new UpdateLoadedPlugins() {
PluginTransformer transformer = new PluginTransformer();
public void execute(PluginDescriptor pluginDescriptor, URL pluginURL) {
Plugin plugin = transformer.toPlugin(pluginDescriptor, pluginURL);
loadedPlugins.add(plugin);
}
};
PluginFinder finder = pluginContainerConfiguration.getPluginFinder();
File tmpDir = pluginContainerConfiguration.getTemporaryDirectory();
List<String> disabledPlugins = pluginContainerConfiguration.getDisabledPlugins();
// The root classloader for all plugins will have all classes hidden except for those configured
// in the regex.
// Notice this root classloader has no jar URLs - it will provide no classes except for what it
// will allow
// the parent to expose as dictated by the regex.
ClassLoader thisClassLoader = this.getClass().getClassLoader();
String rootPluginClassLoaderRegex =
pluginContainerConfiguration.getRootPluginClassLoaderRegex();
ClassLoader rootCL =
new RootPluginClassLoader(new URL[] {}, thisClassLoader, rootPluginClassLoaderRegex);
// build our empty class loader manager - we use it to create and manage our plugin's
// classloaders
Map<String, URL> pluginNamesUrls = new HashMap<String, URL>();
// Save descriptors for later use, so we don't need to parse them twice.
Map<URL, PluginDescriptor> descriptors = new HashMap<URL, PluginDescriptor>();
PluginDependencyGraph graph = new PluginDependencyGraph();
boolean createResourceCL = pluginContainerConfiguration.isCreateResourceClassloaders();
this.classLoaderManager =
new ClassLoaderManager(pluginNamesUrls, graph, rootCL, tmpDir, createResourceCL);
if (finder == null) {
log.warn(
"No plugin finder was specified in the plugin container configuration - this should only occur within test environments.");
return;
}
try {
Collection<URL> pluginUrls = finder.findPlugins();
// first, we need to parse all descriptors so we can build the dependency graph
for (URL url : pluginUrls) {
log.debug("Plugin found at: " + url);
try {
PluginDescriptor descriptor = AgentPluginDescriptorUtil.loadPluginDescriptorFromUrl(url);
if (!disabledPlugins.contains(descriptor.getName())) {
AgentPluginDescriptorUtil.addPluginToDependencyGraph(graph, descriptor);
pluginNamesUrls.put(descriptor.getName(), url);
descriptors.put(url, descriptor);
} else {
log.info("Not loading disabled plugin: " + url);
}
} catch (Throwable t) {
// probably due to invalid XML syntax in the deployment descriptor - the plugin will be
// ignored
log.error(
"Plugin at [" + url + "] could not be loaded and will therefore not be deployed.", t);
continue;
}
}
// our graph is complete, get the order that we have to deploy the plugins
List<String> deploymentOrder = graph.getDeploymentOrder();
// now deploy the plugins in the proper order, making sure we build the proper classloaders
for (String nextPlugin : deploymentOrder) {
URL pluginUrl = pluginNamesUrls.get(nextPlugin);
try {
ClassLoader pluginClassLoader =
this.classLoaderManager.obtainPluginClassLoader(nextPlugin);
PluginDescriptor descriptor = descriptors.get(pluginUrl);
loadPlugin(pluginUrl, pluginClassLoader, descriptor);
} catch (Throwable t) {
// for some reason, the plugin failed to load - it will be ignored, and its depending
// plugins will also fail later
log.error(
"Plugin ["
+ nextPlugin
+ "] at ["
+ pluginUrl
+ "] could not be loaded and will therefore not be deployed.",
t);
continue;
}
}
log.info("Deployed plugins: " + this.loadedPlugins);
metadataManager.cleanupDescriptors();
} catch (Exception e) {
shutdown(); // have to clean up the environments (e.g. unpacked jars) we might have already
// created
log.error("Error initializing plugin container", e);
throw new RuntimeException("Cannot initialize the plugin container", e);
}
}