001/* $Id: RuleLoader.java 992060 2010-09-02 19:09:47Z simonetripodi $
002 *
003 * Licensed to the Apache Software Foundation (ASF) under one or more
004 * contributor license agreements.  See the NOTICE file distributed with
005 * this work for additional information regarding copyright ownership.
006 * The ASF licenses this file to You under the Apache License, Version 2.0
007 * (the "License"); you may not use this file except in compliance with
008 * the License.  You may obtain a copy of the License at
009 *
010 *      http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.commons.digester.plugins;
019
020import org.apache.commons.digester.Digester;
021
022/**
023 * Interface for classes which can dynamically load custom
024 * plugin rules associated with a user's plugin class.
025 * <p>
026 * Each plugin declaration has an associated RuleLoader instance, and that
027 * instance's addRules method is invoked each time the input xml specifies
028 * that an instance of that plugged-in class is to be created.
029 * <p>
030 * This is an abstract class rather than an interface in order to make
031 * it possible to enhance this class in future without breaking binary
032 * compatibility; it is possible to add methods to an abstract class, but
033 * not to an interface. 
034 *
035 * @since 1.6
036 */
037
038public abstract class RuleLoader {
039    
040    /**
041     * Configures the digester with custom rules for some plugged-in
042     * class.
043     * <p>
044     * This method is invoked when the start of an xml tag is encountered
045     * which maps to a PluginCreateRule. Any rules added here are removed
046     * from the digester when the end of that xml tag is encountered.
047     */
048    public abstract void addRules(Digester d, String path) throws PluginException;
049}