| //------------------------------------------------------------------------------ |
| //Copyright (c) 2005, 2008 IBM Corporation 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: |
| //IBM Corporation - initial implementation |
| //------------------------------------------------------------------------------ |
| package org.eclipse.epf.common.utils; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| 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.epf.common.CommonPlugin; |
| import org.osgi.framework.Bundle; |
| |
| /** |
| * Helper class with methods to retrieve extensions |
| * Moved part of org.eclipse.epf.library.edit.util.ExtensionManager, to allow |
| * access by classes that have no dependency on org.eclipse.epf.library.edit |
| * |
| * @author Phong Nguyen Le |
| * @author Weiping Lu |
| */ |
| public class ExtensionHelper { |
| private static Map IDToExtensionMap = new HashMap(); |
| |
| public static Object createExtension(String namespace, String extensionPointName) { |
| // Process the contributors. |
| // |
| IExtensionRegistry extensionRegistry = Platform.getExtensionRegistry(); |
| IExtensionPoint extensionPoint = extensionRegistry.getExtensionPoint(namespace, extensionPointName); |
| if (extensionPoint != null) { |
| IExtension[] extensions = extensionPoint.getExtensions(); |
| Object ext = null; |
| ext_walk: |
| for (int i = 0; i < extensions.length; i++) { |
| IExtension extension = extensions[i]; |
| String pluginId = extension.getNamespaceIdentifier(); |
| Bundle bundle = Platform.getBundle(pluginId); |
| IConfigurationElement[] configElements = extension |
| .getConfigurationElements(); |
| for (int j = 0; j < configElements.length; j++) { |
| IConfigurationElement configElement = configElements[j]; |
| try { |
| String className = configElement.getAttribute("class"); //$NON-NLS-1$ |
| if(className != null) { |
| ext = bundle.loadClass(className).newInstance(); |
| break ext_walk; |
| } |
| } catch (Exception e) { |
| CommonPlugin.getDefault().getLogger().logError(e); |
| } |
| } |
| } |
| return ext; |
| } |
| return null; |
| } |
| |
| public static Object getExtension(String namespace, String extensionPointName) { |
| String ID = namespace + '.' + extensionPointName; |
| Object ext = IDToExtensionMap.get(ID); |
| if(ext == null) { |
| synchronized (IDToExtensionMap) { |
| ext = IDToExtensionMap.get(ID); |
| if(ext == null) { |
| ext = createExtension(namespace, extensionPointName); |
| if(ext != null) { |
| IDToExtensionMap.put(ID, ext); |
| } |
| } |
| } |
| |
| } |
| return ext; |
| } |
| |
| /** |
| * Create object based on type and context through extension |
| * @param type |
| * @param context |
| * @return created object or null if no extension is found |
| */ |
| public static Object create(Class type, Object context) { |
| IObjectFactory ret = (IObjectFactory) getExtension( |
| CommonPlugin.getDefault().getId(), "objectFactory");//$NON-NLS-1$ |
| if (ret == null) { |
| return null; |
| } |
| return ret.create(type, context); |
| } |
| |
| } |