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.message;
021
022import org.apache.james.mime4j.MimeException;
023import org.apache.james.mime4j.codec.DecodeMonitor;
024import org.apache.james.mime4j.dom.FieldParser;
025import org.apache.james.mime4j.dom.Header;
026import org.apache.james.mime4j.dom.field.ParsedField;
027import org.apache.james.mime4j.field.LenientFieldParser;
028import org.apache.james.mime4j.parser.AbstractContentHandler;
029import org.apache.james.mime4j.stream.Field;
030
031/**
032 * Abstract implementation of ContentHandler that automates common
033 * tasks. Currently performs header parsing.
034 *
035 * Older versions of this class performed decoding of content streams.
036 * This can be now easily achieved by calling setContentDecoding(true) on the MimeStreamParser.
037 */
038public abstract class SimpleContentHandler extends AbstractContentHandler {
039
040    private final FieldParser<? extends ParsedField> fieldParser;
041    private final DecodeMonitor monitor;
042
043    public SimpleContentHandler(
044            final FieldParser<? extends ParsedField> fieldParser,
045            final DecodeMonitor monitor) {
046        super();
047        this.fieldParser = fieldParser != null ? fieldParser : LenientFieldParser.getParser();
048        this.monitor = monitor != null ? monitor : DecodeMonitor.SILENT;
049    }
050
051    public SimpleContentHandler() {
052        this(null, null);
053    }
054
055    /**
056     * Called after headers are parsed.
057     */
058    public abstract void headers(Header header);
059
060    /* Implement introduced callbacks. */
061
062    private Header currHeader;
063
064    /**
065     * @see org.apache.james.mime4j.parser.AbstractContentHandler#startHeader()
066     */
067    @Override
068    public final void startHeader() {
069        currHeader = new HeaderImpl();
070    }
071
072    /**
073     * @see org.apache.james.mime4j.parser.AbstractContentHandler#field(Field)
074     */
075    @Override
076    public final void field(Field field) throws MimeException {
077        ParsedField parsedField;
078        if (field instanceof ParsedField) {
079            parsedField = (ParsedField) field;
080        } else {
081            parsedField = fieldParser.parse(field, monitor);
082        }
083        currHeader.addField(parsedField);
084    }
085
086    /**
087     * @see org.apache.james.mime4j.parser.AbstractContentHandler#endHeader()
088     */
089    @Override
090    public final void endHeader() {
091        Header tmp = currHeader;
092        currHeader = null;
093        headers(tmp);
094    }
095
096}