001/* $Id: RuleLoader.java 471661 2006-11-06 08:09:25Z skitching $
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 */ 
018 
019package org.apache.commons.digester.plugins;
020
021import org.apache.commons.digester.Digester;
022
023/**
024 * Interface for classes which can dynamically load custom
025 * plugin rules associated with a user's plugin class.
026 * <p>
027 * Each plugin declaration has an associated RuleLoader instance, and that
028 * instance's addRules method is invoked each time the input xml specifies
029 * that an instance of that plugged-in class is to be created.
030 * <p>
031 * This is an abstract class rather than an interface in order to make
032 * it possible to enhance this class in future without breaking binary
033 * compatibility; it is possible to add methods to an abstract class, but
034 * not to an interface. 
035 *
036 * @since 1.6
037 */
038
039public abstract class RuleLoader {
040    
041    /**
042     * Configures the digester with custom rules for some plugged-in
043     * class.
044     * <p>
045     * This method is invoked when the start of an xml tag is encountered
046     * which maps to a PluginCreateRule. Any rules added here are removed
047     * from the digester when the end of that xml tag is encountered.
048     */
049    public abstract void addRules(Digester d, String path) throws PluginException;
050}