| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| /* $Id$ */ |
| |
| package org.apache.fop.util; |
| |
| import java.util.Iterator; |
| import java.util.Map; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| |
| import org.apache.xmlgraphics.util.Service; |
| |
| /** |
| * This class holds references to various XML handlers used by FOP. It also |
| * supports automatic discovery of additional XML handlers available through |
| * the class path. |
| */ |
| public class ContentHandlerFactoryRegistry { |
| |
| /** the logger */ |
| private static Log log = LogFactory.getLog(ContentHandlerFactoryRegistry.class); |
| |
| /** Map from namespace URIs to ContentHandlerFactories */ |
| private Map factories = new java.util.HashMap(); |
| |
| /** |
| * Default constructor. |
| */ |
| public ContentHandlerFactoryRegistry() { |
| discover(); |
| } |
| |
| /** |
| * Add an XML handler. The handler itself is inspected to find out what it supports. |
| * @param classname the fully qualified class name |
| */ |
| public void addContentHandlerFactory(String classname) { |
| try { |
| ContentHandlerFactory factory |
| = (ContentHandlerFactory)Class.forName(classname).newInstance(); |
| addContentHandlerFactory(factory); |
| } catch (ClassNotFoundException e) { |
| throw new IllegalArgumentException("Could not find " |
| + classname); |
| } catch (InstantiationException e) { |
| throw new IllegalArgumentException("Could not instantiate " |
| + classname); |
| } catch (IllegalAccessException e) { |
| throw new IllegalArgumentException("Could not access " |
| + classname); |
| } catch (ClassCastException e) { |
| throw new IllegalArgumentException(classname |
| + " is not an " |
| + ContentHandlerFactory.class.getName()); |
| } |
| } |
| |
| /** |
| * Add an ContentHandlerFactory. The instance is inspected to find out what it supports. |
| * @param factory the ContentHandlerFactory instance |
| */ |
| public void addContentHandlerFactory(ContentHandlerFactory factory) { |
| String[] ns = factory.getSupportedNamespaces(); |
| for (int i = 0; i < ns.length; i++) { |
| factories.put(ns[i], factory); |
| } |
| } |
| |
| /** |
| * Retrieves a ContentHandlerFactory instance of a given namespace URI. |
| * @param namespaceURI the namespace to be handled. |
| * @return the ContentHandlerFactory or null, if no suitable instance is available. |
| */ |
| public ContentHandlerFactory getFactory(String namespaceURI) { |
| ContentHandlerFactory factory = (ContentHandlerFactory)factories.get(namespaceURI); |
| return factory; |
| } |
| |
| /** |
| * Discovers ContentHandlerFactory implementations through the classpath and dynamically |
| * registers them. |
| */ |
| private void discover() { |
| // add mappings from available services |
| Iterator providers = Service.providers(ContentHandlerFactory.class); |
| if (providers != null) { |
| while (providers.hasNext()) { |
| ContentHandlerFactory factory = (ContentHandlerFactory)providers.next(); |
| try { |
| if (log.isDebugEnabled()) { |
| log.debug("Dynamically adding ContentHandlerFactory: " |
| + factory.getClass().getName()); |
| } |
| addContentHandlerFactory(factory); |
| } catch (IllegalArgumentException e) { |
| log.error("Error while adding ContentHandlerFactory", e); |
| } |
| |
| } |
| } |
| } |
| } |