StagemonitorPlugin.java

package org.stagemonitor.core;

import org.stagemonitor.configuration.ConfigurationRegistry;
import org.stagemonitor.configuration.ConfigurationOptionProvider;
import org.stagemonitor.core.metrics.metrics2.Metric2Registry;

import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;

/**
 * Base class for stagemonitor Plugins.
 *
 * The {@link #initializePlugin(InitArguments)} )} method serves as a initialisation callback
 * for plugins.
 */
public abstract class StagemonitorPlugin extends ConfigurationOptionProvider implements StagemonitorSPI {

	volatile boolean initialized;
	List<Runnable> onInitCallbacks = new CopyOnWriteArrayList<Runnable>();

	public boolean isInitialized() {
		return initialized;
	}

	/**
	 * Implementing classes have to initialize the plugin by registering their metrics the
	 * {@link Metric2Registry}
	 * @param initArguments
	 */
	public void initializePlugin(InitArguments initArguments) throws Exception {
	}

	/**
	 * This method is called when stagemonitor shuts down.
	 * The shutdown is triggered by {@link org.stagemonitor.web.monitor.filter.HttpRequestMonitorFilter#destroy()},
	 * for example. In non-servlet applications this method has to be called manually.
	 * <p>
	 * Note that this method will be called even if {@link #initializePlugin(InitArguments)} has not been called.
	 */
	public void onShutDown() throws Exception {
	}

	/**
	 * StagemonitorPlugins can add additional tabs to the in browser widget.
	 * A tab plugin consists of a javascript file and a html file.
	 * <p/>
	 * The files should be placed under
	 * <code>src/main/resources/stagemonitor/static/some/sub/folder/myPlugin[.js|.html]</code>
	 * if you return the path <code>/stagemonitor/static/some/sub/folder/myPlugin</code>
	 * <p/>
	 * The FileServlet serves all files under /src/main/resources/stagemonitor/static and
	 * src/main/resources/stagemonitor/public/static
	 */
	public void registerWidgetTabPlugins(WidgetTabPluginsRegistry widgetTabPluginsRegistry) {
	}

	/**
	 * StagemonitorPlugins can extend the metrics tab in the in browser widget.
	 * A widget metrics tab plugin consists of a javascript file and a html file.
	 * <p/>
	 * The files should be placed under
	 * <code>/src/main/resources/stagemonitor/static/some/sub/folder/{pluginId}[.js|.html]</code>
	 * <p/>
	 * The FileServlet serves all files under /src/main/resources/stagemonitor/static and
	 * /src/main/resources/stagemonitor/public/static
	 * <p/>
	 * For documentation and a example of how a plugin should look like, see
	 * <code>stagemonitor-ehcache/src/main/resources/stagemonitor/static/tabs/metrics</code> and
	 * <code>stagemonitor-jvm/src/main/resources/stagemonitor/static/tabs/metrics</code>
	 */
	public void registerWidgetMetricTabPlugins(WidgetMetricTabPluginsRegistry widgetMetricTabPluginsRegistry) {
	}

	/**
	 * If this plugin is initialized, the callback is executed immediately. Otherwise, it is executed after the plugin
	 * has been initialized.
	 *
	 * @param onInitCallback the callback which is not executed in a different thread
	 */
	public void onInit(Runnable onInitCallback) {
		if (initialized) {
			onInitCallback.run();
		} else {
			onInitCallbacks.add(onInitCallback);
		}
	}

	public static class InitArguments {
		private final Metric2Registry metricRegistry;
		private final ConfigurationRegistry configuration;
		private final MeasurementSession measurementSession;

		public InitArguments(Metric2Registry metricRegistry, ConfigurationRegistry configuration, MeasurementSession measurementSession) {
			this.metricRegistry = metricRegistry;
			this.configuration = configuration;
			this.measurementSession = measurementSession;
		}

		public Metric2Registry getMetricRegistry() {
			return metricRegistry;
		}

		public ConfigurationRegistry getConfiguration() {
			return configuration;
		}

		public <T extends StagemonitorPlugin> T getPlugin(Class<T> plugin) {
			return configuration.getConfig(plugin);
		}

		public MeasurementSession getMeasurementSession() {
			return measurementSession;
		}
	}

	public static class WidgetTabPluginsRegistry {
		private final List<String> pathsOfWidgetTabPlugins;

		WidgetTabPluginsRegistry(List<String> pathsOfWidgetTabPlugins) {
			this.pathsOfWidgetTabPlugins = pathsOfWidgetTabPlugins;
		}

		public void addWidgetTabPlugin(String pathOfWidgetTabPlugin) {
			pathsOfWidgetTabPlugins.add(pathOfWidgetTabPlugin);
		}
	}

	public static class WidgetMetricTabPluginsRegistry {
		private final List<String> pathsOfWidgetMetricTabPlugins;

		WidgetMetricTabPluginsRegistry(List<String> pathsOfWidgetMetricTabPlugins) {
			this.pathsOfWidgetMetricTabPlugins = pathsOfWidgetMetricTabPlugins;
		}

		public void addWidgetMetricTabPlugin(String pathOfWidgetMetricTabPlugin) {
			pathsOfWidgetMetricTabPlugins.add(pathOfWidgetMetricTabPlugin);
		}
	}
}