Java tutorial
/***************************************************************************** * Java Plug-in Framework (JPF) * Copyright (C) 2004-2006 Dmitry Olshansky * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA *****************************************************************************/ package org.java.plugin.standard; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.java.plugin.ObjectFactory; import org.java.plugin.PathResolver; import org.java.plugin.PluginManager; import org.java.plugin.registry.PluginRegistry; import org.java.plugin.util.ExtendedProperties; /** * Standard object factory implementation. * @version $Id: StandardObjectFactory.java,v 1.8 2006/06/05 18:16:43 ddimon Exp $ */ public class StandardObjectFactory extends ObjectFactory { static final String PACKAGE_NAME = "org.java.plugin.standard"; //$NON-NLS-1$ protected Log log = LogFactory.getLog(getClass()); protected ExtendedProperties config; /** * @see org.java.plugin.ObjectFactory#configure(ExtendedProperties) */ protected void configure(final ExtendedProperties configuration) { config = (configuration != null) ? configuration : new ExtendedProperties(); } protected String getImplClassName(final Class cls) { String result = config.getProperty(cls.getName(), null); if (log.isDebugEnabled()) { log.debug("implementation class for " + cls.getName() //$NON-NLS-1$ + " is " + result); //$NON-NLS-1$ } return result; } protected Object createClassInstance(final String className) throws InstantiationException, IllegalAccessException, ClassNotFoundException { ClassLoader cl = Thread.currentThread().getContextClassLoader(); if (cl != null) { try { return cl.loadClass(className).newInstance(); } catch (ClassNotFoundException cnfe) { // ignore } } cl = getClass().getClassLoader(); if (cl != null) { try { return cl.loadClass(className).newInstance(); } catch (ClassNotFoundException cnfe) { // ignore } } return ClassLoader.getSystemClassLoader().loadClass(className).newInstance(); } /** * @see org.java.plugin.ObjectFactory#createRegistry() */ public PluginRegistry createRegistry() { String className = getImplClassName(PluginRegistry.class); PluginRegistry result; if (className == null) { className = "org.java.plugin.registry.xml.PluginRegistryImpl"; //$NON-NLS-1$ } try { result = (PluginRegistry) createClassInstance(className); } catch (Exception e) { log.fatal("failed creating registry instance " //$NON-NLS-1$ + className, e); throw new Error("failed creating registry instance " //$NON-NLS-1$ + className, e); } result.configure(config.getSubset(className + ".")); //$NON-NLS-1$ log.debug("registry instance created - " + result); //$NON-NLS-1$ return result; } /** * @see org.java.plugin.ObjectFactory#createPathResolver() */ public PathResolver createPathResolver() { String className = getImplClassName(PathResolver.class); PathResolver result; if (className == null) { className = "org.java.plugin.standard.StandardPathResolver"; //$NON-NLS-1$ } try { result = (PathResolver) createClassInstance(className); } catch (Exception e) { log.fatal("failed creating path resolver instance " //$NON-NLS-1$ + className, e); throw new Error("failed creating path resolver instance " //$NON-NLS-1$ + className, e); } try { result.configure(config.getSubset(className + ".")); //$NON-NLS-1$ } catch (Exception e) { log.fatal("failed configuring path resolver instance " //$NON-NLS-1$ + result, e); throw new Error("failed configuring path resolver instance " //$NON-NLS-1$ + result, e); } log.debug("path resolver instance created - " + result); //$NON-NLS-1$ return result; } /** * Creates new instance of plug-in life cycle handler implementation class * using standard discovery algorithm to determine which handler * implementation class should be instantiated. * @return new plug-in life cycle handler instance */ protected PluginLifecycleHandler createLifecycleHandler() { String className = getImplClassName(PluginLifecycleHandler.class); PluginLifecycleHandler result; if (className == null) { className = "org.java.plugin.standard.StandardPluginLifecycleHandler"; //$NON-NLS-1$ } try { result = (PluginLifecycleHandler) createClassInstance(className); } catch (Exception e) { log.fatal("failed creating plug-in life cycle handler instance " //$NON-NLS-1$ + className, e); throw new Error("failed creating plug-in life cycle handler instance " //$NON-NLS-1$ + className, e); } result.configure(config.getSubset(className + ".")); //$NON-NLS-1$ log.debug("life cycle handler instance created - " + result); //$NON-NLS-1$ return result; } /** * @see org.java.plugin.ObjectFactory#createManager( * org.java.plugin.registry.PluginRegistry, * org.java.plugin.PathResolver) */ public PluginManager createManager(final PluginRegistry registry, final PathResolver pathResolver) { return new StandardPluginManager(registry, pathResolver, createLifecycleHandler()); } }