001package org.apache.commons.digester3.examples.plugins.pipeline;
002
003/*
004 * Licensed to the Apache Software Foundation (ASF) under one or more
005 * contributor license agreements.  See the NOTICE file distributed with
006 * this work for additional information regarding copyright ownership.
007 * The ASF licenses this file to You under the Apache License, Version 2.0
008 * (the "License"); you may not use this file except in compliance with
009 * the License.  You may obtain a copy of the License at
010 * 
011 *      http://www.apache.org/licenses/LICENSE-2.0
012 * 
013 * Unless required by applicable law or agreed to in writing, software
014 * distributed under the License is distributed on an "AS IS" BASIS,
015 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
016 * See the License for the specific language governing permissions and
017 * limitations under the License.
018 */ 
019
020import java.util.LinkedList;
021import java.util.Iterator;
022
023import org.apache.commons.digester3.Digester;
024import org.apache.commons.digester3.plugins.PluginCreateRule;
025
026/**
027 * An implementation of the Transform interface which is configured with
028 * a sequence of "subtransforms", and applies them one by one to the input
029 * data.
030 * <p>
031 * This demonstrates that a plugged-in class can itself define plugin-points 
032 * for user-defined classes if it wishes.
033 */
034public class CompoundTransform
035    implements Transform
036{
037
038    private LinkedList<Transform> transforms = new LinkedList<Transform>();
039
040    public void addTransform( Transform transform )
041    {
042        transforms.add( transform );
043    }
044
045    public String transform( String s )
046    {
047        for ( Iterator<Transform> i = transforms.iterator(); i.hasNext(); )
048        {
049            Transform t = i.next();
050            s = t.transform( s );
051        }
052        return s;
053    }
054
055    public static void addRules( Digester d, String patternPrefix )
056    {
057        PluginCreateRule pcr = new PluginCreateRule( Transform.class );
058        d.addRule( patternPrefix + "/subtransform", pcr );
059        d.addSetNext( patternPrefix + "/subtransform", "addTransform" );
060    }
061
062}