package org.apache.commons.digester3.plugins;

/*
 * 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.
 */

import org.apache.commons.digester3.Digester;

/**
 * Interface for classes which can dynamically load custom plugin rules associated with a user's plugin class.
 * <p>
 * Each plugin declaration has an associated RuleLoader instance, and that instance's addRules method is invoked each
 * time the input xml specifies that an instance of that plugged-in class is to be created.
 * <p>
 * This is an abstract class rather than an interface in order to make it possible to enhance this class in future
 * without breaking binary compatibility; it is possible to add methods to an abstract class, but not to an interface.
 * 
 * @since 1.6
 */
public abstract class RuleLoader
{

    /**
     * Configures the digester with custom rules for some plugged-in class.
     * <p>
     * This method is invoked when the start of an xml tag is encountered which maps to a PluginCreateRule. Any rules
     * added here are removed from the digester when the end of that xml tag is encountered.
     *
     * @param d The gigester has to be configured
     * @param path The path where rule has to be bound
     * @throws PluginException if any error occurs
     */
    public abstract void addRules( Digester d, String path )
        throws PluginException;

}