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
020package org.apache.james.mime4j.field;
021
022import java.util.Locale;
023
024import org.apache.james.mime4j.codec.DecodeMonitor;
025import org.apache.james.mime4j.dom.FieldParser;
026import org.apache.james.mime4j.dom.field.ContentTransferEncodingField;
027import org.apache.james.mime4j.stream.Field;
028import org.apache.james.mime4j.util.MimeUtil;
029
030/**
031 * Represents a <code>Content-Transfer-Encoding</code> field.
032 */
033public 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}