001    /****************************************************************
002     * Licensed to the Apache Software Foundation (ASF) under one   *
003     * or more contributor license agreements.  See the NOTICE file *
004     * distributed with this work for additional information        *
005     * regarding copyright ownership.  The ASF licenses this file   *
006     * to you under the Apache License, Version 2.0 (the            *
007     * "License"); you may not use this file except in compliance   *
008     * with 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,   *
013     * software distributed under the License is distributed on an  *
014     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY       *
015     * KIND, either express or implied.  See the License for the    *
016     * specific language governing permissions and limitations      *
017     * under the License.                                           *
018     ****************************************************************/
019    
020    package org.apache.james.mime4j.field;
021    
022    import java.util.HashMap;
023    import java.util.Map;
024    
025    import org.apache.james.mime4j.codec.DecodeMonitor;
026    import org.apache.james.mime4j.dom.FieldParser;
027    import org.apache.james.mime4j.dom.field.ParsedField;
028    import org.apache.james.mime4j.stream.Field;
029    
030    public class DelegatingFieldParser implements FieldParser<ParsedField> {
031    
032        private final FieldParser<? extends ParsedField> defaultParser;
033        private final Map<String, FieldParser<? extends ParsedField>> parsers;
034    
035        public DelegatingFieldParser(final FieldParser<? extends ParsedField> defaultParser) {
036            super();
037            this.defaultParser = defaultParser;
038            this.parsers = new HashMap<String, FieldParser<? extends ParsedField>>();
039        }
040    
041        /**
042         * Sets the parser used for the field named <code>name</code>.
043         * @param name the name of the field
044         * @param parser the parser for fields named <code>name</code>
045         */
046        public void setFieldParser(final String name, final FieldParser<? extends ParsedField> parser) {
047            parsers.put(name.toLowerCase(), parser);
048        }
049    
050        public FieldParser<? extends ParsedField> getParser(final String name) {
051            final FieldParser<? extends ParsedField> field = parsers.get(name.toLowerCase());
052            if (field == null) {
053                return defaultParser;
054            }
055            return field;
056        }
057    
058        public ParsedField parse(final Field rawField, final DecodeMonitor monitor) {
059            final FieldParser<? extends ParsedField> parser = getParser(rawField.getName());
060            return parser.parse(rawField, monitor);
061        }
062    }