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.mina.example.sumup.codec;
021
022import org.apache.mina.core.buffer.IoBuffer;
023import org.apache.mina.core.session.IoSession;
024import org.apache.mina.example.sumup.message.AbstractMessage;
025import org.apache.mina.example.sumup.message.ResultMessage;
026import org.apache.mina.filter.codec.ProtocolDecoderOutput;
027import org.apache.mina.filter.codec.demux.MessageDecoder;
028
029/**
030 * A {@link MessageDecoder} that decodes {@link ResultMessage}.
031 *
032 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
033 */
034public class ResultMessageDecoder extends AbstractMessageDecoder {
035    private int code;
036
037    private boolean readCode;
038
039    public ResultMessageDecoder() {
040        super(Constants.RESULT);
041    }
042
043    @Override
044    protected AbstractMessage decodeBody(IoSession session, IoBuffer in) {
045        if (!readCode) {
046            if (in.remaining() < Constants.RESULT_CODE_LEN) {
047                return null; // Need more data.
048            }
049
050            code = in.getShort();
051            readCode = true;
052        }
053
054        if (code == Constants.RESULT_OK) {
055            if (in.remaining() < Constants.RESULT_VALUE_LEN) {
056                return null;
057            }
058
059            ResultMessage m = new ResultMessage();
060            m.setOk(true);
061            m.setValue(in.getInt());
062            readCode = false;
063            return m;
064        } else {
065            ResultMessage m = new ResultMessage();
066            m.setOk(false);
067            readCode = false;
068            return m;
069        }
070    }
071
072    public void finishDecode(IoSession session, ProtocolDecoderOutput out)
073            throws Exception {
074    }
075}