001    /**
002     *
003     * Copyright 2004 Protique Ltd
004     *
005     * Licensed under the Apache License, Version 2.0 (the "License");
006     * you may not use this file except in compliance with the License.
007     * You may obtain a copy of the License at
008     *
009     * http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     *
017     **/
018    
019    package org.activemq.io.impl;
020    import java.io.DataInput;
021    import java.io.IOException;
022    import org.activemq.message.Packet;
023    import org.activemq.message.WireFormatInfo;
024    
025    /**
026     * Reads a ConnnectionInfo object from a Stream
027     * 
028     * @version $Revision: 1.1.1.1 $
029     */
030    public class WireFormatInfoReader extends AbstractPacketReader {
031        
032        AbstractDefaultWireFormat wireFormat;
033        
034        WireFormatInfoReader(){
035        }
036        
037        WireFormatInfoReader(AbstractDefaultWireFormat format){
038            this.wireFormat = format;
039        }
040        /**
041         * Return the type of Packet
042         * 
043         * @return integer representation of the type of Packet
044         */
045        public int getPacketType() {
046            return Packet.WIRE_FORMAT_INFO;
047        }
048    
049        /**
050         * @return a new Packet instance
051         */
052        public Packet createPacket() {
053            return new WireFormatInfo();
054        }
055    
056        /**
057         * build a Packet instance from the data input stream
058         * 
059         * @param packet A Packet object
060         * @param dataIn the data input stream to build the packet from
061         * @throws IOException
062         */
063        public void buildPacket(Packet packet, DataInput dataIn) throws IOException {
064    
065            // The Magic has to match.
066            for( int i=0; i < WireFormatInfo.MAGIC.length; i++ ) {
067                if( dataIn.readByte() != WireFormatInfo.MAGIC[i]) {
068                    throw new IOException("Invalid WireFormatInfo packet.");
069                }
070            }
071            
072            super.buildPacket(packet, dataIn);
073            WireFormatInfo info = (WireFormatInfo) packet;
074            info.setVersion(dataIn.readInt());
075            if (wireFormat != null){
076                wireFormat.setCurrentWireFormatVersion(info.getVersion());
077            }
078        }
079    }