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.Locale;
023    
024    import org.apache.james.mime4j.codec.DecodeMonitor;
025    import org.apache.james.mime4j.dom.FieldParser;
026    import org.apache.james.mime4j.dom.field.ContentTransferEncodingField;
027    import org.apache.james.mime4j.stream.Field;
028    import org.apache.james.mime4j.util.MimeUtil;
029    
030    /**
031     * Represents a <code>Content-Transfer-Encoding</code> field.
032     */
033    public class ContentTransferEncodingFieldImpl extends AbstractField implements ContentTransferEncodingField {
034    
035        private boolean parsed = false;
036        private String encoding;
037    
038        ContentTransferEncodingFieldImpl(Field rawField, DecodeMonitor monitor) {
039            super(rawField, monitor);
040        }
041    
042        private void parse() {
043            parsed = true;
044            String body = getBody();
045            if (body != null) {
046                encoding = body.trim().toLowerCase(Locale.US);
047            } else {
048                encoding = null;
049            }
050        }
051    
052        /**
053         * @see org.apache.james.mime4j.dom.field.ContentTransferEncodingField#getEncoding()
054         */
055        public String getEncoding() {
056            if (!parsed) {
057                parse();
058            }
059            return encoding;
060        }
061    
062        /**
063         * Gets the encoding of the given field if. Returns the default
064         * <code>7bit</code> if not set or if <code>f</code> is
065         * <code>null</code>.
066         *
067         * @return the encoding.
068         */
069        public static String getEncoding(ContentTransferEncodingField f) {
070            if (f != null && f.getEncoding().length() != 0) {
071                return f.getEncoding();
072            }
073            return MimeUtil.ENC_7BIT;
074        }
075    
076        public static final FieldParser<ContentTransferEncodingField> PARSER = new FieldParser<ContentTransferEncodingField>() {
077    
078            public ContentTransferEncodingField parse(final Field rawField, final DecodeMonitor monitor) {
079                return new ContentTransferEncodingFieldImpl(rawField, monitor);
080            }
081    
082        };
083    }