001    package org.apache.commons.digester3.substitution;
002    
003    /*
004     * Licensed to the Apache Software Foundation (ASF) under one
005     * or more contributor license agreements.  See the NOTICE file
006     * distributed with this work for additional information
007     * regarding copyright ownership.  The ASF licenses this file
008     * to you under the Apache License, Version 2.0 (the
009     * "License"); you may not use this file except in compliance
010     * with the License.  You may obtain a copy of the License at
011     *
012     *   http://www.apache.org/licenses/LICENSE-2.0
013     *
014     * Unless required by applicable law or agreed to in writing,
015     * software distributed under the License is distributed on an
016     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017     * KIND, either express or implied.  See the License for the
018     * specific language governing permissions and limitations
019     * under the License.
020     */
021    
022    import org.apache.commons.digester3.Substitutor;
023    import org.xml.sax.Attributes;
024    
025    /**
026     * This Substitutor chains two Substitutors <code>a</code> and <code>b</code>.
027     * All values to substitute are first handled by <code>a</code> and passed to
028     * <code>b</code> afterwards.
029     */
030    public class CompoundSubstitutor
031        extends Substitutor
032    {
033    
034        /**
035         * Substitutor a
036         */
037        private final Substitutor a;
038    
039        /**
040         * Substitutor b
041         */
042        private final Substitutor b;
043    
044        /**
045         * Creates a new CompoundSubstitutor instance. All values overgiven to <code>substitute()</code>
046         * are first handled by <code>a</code> and passed to <code>b</code> afterwards.
047         * Both Substitutor have to be not null.
048         *
049         * @param a Substitutor a
050         * @param b Substitutor b
051         */
052        public CompoundSubstitutor( Substitutor a, Substitutor b )
053        {
054            if ( a == null )
055            {
056                throw new IllegalArgumentException( "First Substitutor must be not null" );
057            }
058            if ( b == null )
059            {
060                throw new IllegalArgumentException( "Second Substitutor must be not null" );
061            }
062            this.a = a;
063            this.b = b;
064        }
065    
066        /**
067         * {@inheritDoc}
068         */
069        @Override
070        public Attributes substitute( Attributes attributes )
071        {
072            return b.substitute( a.substitute( attributes ) );
073        }
074    
075        /**
076         * {@inheritDoc}
077         */
078        @Override
079        public String substitute( String bodyText )
080        {
081            return b.substitute( a.substitute( bodyText ) );
082        }
083    
084    }