path: root/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasklist/internal/TaskListExtensionReader.java

/*******************************************************************************
 * Copyright (c) 2004 - 2005 University Of British Columbia and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     University Of British Columbia - initial API and implementation
 *******************************************************************************/
package org.eclipse.mylar.tasklist.internal;

import java.util.List;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtension;
import org.eclipse.core.runtime.IExtensionPoint;
import org.eclipse.core.runtime.IExtensionRegistry;
import org.eclipse.core.runtime.Platform;
import org.eclipse.mylar.core.MylarPlugin;
import org.eclipse.mylar.tasklist.ITaskHandler;
import org.eclipse.mylar.tasklist.ITaskListDynamicSubMenuContributor;
import org.eclipse.mylar.tasklist.ITaskListExternalizer;
import org.eclipse.mylar.tasklist.ITaskActivationListener;
import org.eclipse.mylar.tasklist.MylarTasklistPlugin;

/**
 * @author Shawn Minto
 */
public class TaskListExtensionReader {
	private static boolean extensionsRead = false;
	private static TaskListExtensionReader thisReader = new TaskListExtensionReader();
	
	// read the extensions and load the required plugins
	public static void initExtensions(List<ITaskListExternalizer> externalizers, DefaultTaskListExternalizer defaultExternalizer) {
		// code from "contributing to eclipse" with modifications for deprecated code
		if(!extensionsRead){
			IExtensionRegistry registry = Platform.getExtensionRegistry();
			IExtensionPoint extensionPoint = registry.getExtensionPoint(MylarTasklistPlugin.TASK_CONTRIBUTOR_EXTENSION_POINT_ID);
			IExtension[] extensions = extensionPoint.getExtensions();
			for(int i = 0; i < extensions.length; i++){
				IConfigurationElement[] elements = extensions[i].getConfigurationElements();
				for(int j = 0; j < elements.length; j++){
					if(elements[j].getName().compareTo(MylarTasklistPlugin.TASK_HANDLER_ELEMENT) == 0){
						readTaskHandler(elements[j], externalizers);
					} else if(elements[j].getName().compareTo(MylarTasklistPlugin.TASK_LISTENER_ELEMENT) == 0){
						readTaskListener(elements[j]);
					} else if(elements[j].getName().compareTo(MylarTasklistPlugin.DYNAMIC_POPUP_ELEMENT) == 0){
						readDynamicPopupContributor(elements[j]);
					}
				}
			}
			defaultExternalizer.setExternalizers(externalizers);
			extensionsRead = true;
		}
	}

	private static void readTaskListener(IConfigurationElement element) {
		try{
			Object taskListener = element.createExecutableExtension(MylarTasklistPlugin.TASK_LISTENER_CLASS_ID);
			if (taskListener instanceof ITaskActivationListener) {
				MylarTasklistPlugin.getDefault().addTaskListListener((ITaskActivationListener) taskListener);
			} else {
				MylarPlugin.log("Could not load tasklist listener: " + taskListener.getClass().getCanonicalName() + " must implement " + ITaskActivationListener.class.getCanonicalName(), thisReader);	
			}
		} catch (CoreException e){
			MylarPlugin.log(e, "Could not load tasklist listener extension");
		}
	}

	private static void readDynamicPopupContributor(IConfigurationElement element) {
		try{
			Object dynamicPopupContributor = element.createExecutableExtension(MylarTasklistPlugin.DYNAMIC_POPUP_CLASS_ID);
			if (dynamicPopupContributor instanceof ITaskListDynamicSubMenuContributor) {
				MylarTasklistPlugin.getDefault().addDynamicPopupContributor((ITaskListDynamicSubMenuContributor) dynamicPopupContributor);
			} else {
				MylarPlugin.log("Could not load dyanmic popup menu: " + dynamicPopupContributor.getClass().getCanonicalName() + " must implement " + ITaskListDynamicSubMenuContributor.class.getCanonicalName(), thisReader);	
			}
		} catch (CoreException e){
			MylarPlugin.log(e, "Could not load dynamic popup extension");
		}
	}

	private static void readTaskHandler(IConfigurationElement element, List<ITaskListExternalizer> externalizers) {
		try{
			Object externalizer = element.createExecutableExtension(MylarTasklistPlugin.EXTERNALIZER_CLASS_ID);
			if (externalizer instanceof ITaskListExternalizer) {
				externalizers.add((ITaskListExternalizer) externalizer);
			} else {
				MylarPlugin.log("Could not load externalizer: " + externalizer.getClass().getCanonicalName() + " must implement " + ITaskListExternalizer.class.getCanonicalName(), thisReader);	
			}
			
			Object taskHandler = element.createExecutableExtension(MylarTasklistPlugin.ACTION_CONTRIBUTOR_CLASS_ID);
			if (taskHandler instanceof ITaskHandler) {
				MylarTasklistPlugin.getDefault().addTaskHandler((ITaskHandler) taskHandler);
				
			}else {
				MylarPlugin.log("Could not load contributor: " + taskHandler.getClass().getCanonicalName() + " must implement " + ITaskHandler.class.getCanonicalName(), thisReader);	
			}
		} catch (CoreException e){
			MylarPlugin.log(e, "Could not load task handler extension");
		}
	}
}