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AZMessageFactory.javaAPI DocAzureus 3.0.3.410935Sat Sep 01 06:58:38 BST 2007com.aelitis.azureus.core.peermanager.messaging.azureus

AZMessageFactory

public class AZMessageFactory extends Object
Factory for handling AZ message creation. NOTE: wire format: [total message length] + [id length] + [id bytes] + [version byte] + [payload bytes]

Fields Summary
public static final byte
MESSAGE_VERSION_INITIAL
public static final byte
MESSAGE_VERSION_SUPPORTS_PADDING
public static final int
AZ_HANDSHAKE_PAD_MAX
public static final int
SMALL_PAD_MAX
public static final int
BIG_PAD_MAX
private static final byte
bss
private static final Map
legacy_data
Constructors Summary
Methods Summary
public static MessagecreateAZMessage(DirectByteBuffer stream_payload)
Construct a new AZ message instance from the given message raw byte stream.

param
stream_payload data
return
decoded/deserialized AZ message
throws
MessageException if message creation failed. NOTE: Does not auto-return to buffer pool the given direct buffer on thrown exception.

    int id_length = stream_payload.getInt( bss );

    if( id_length < 1 || id_length > 1024 || id_length > stream_payload.remaining( bss ) - 1 ) {
      byte bt_id = stream_payload.get( (byte)0, 0 );
      throw new MessageException( "invalid AZ id length given: " +id_length+ ", stream_payload.remaining(): " +stream_payload.remaining( bss )+ ", BT id?=" +bt_id );
    }
    
    byte[] id_bytes = new byte[ id_length ];
    
    stream_payload.get( bss, id_bytes );
    
    	// if only the version came first we could save a lot of space by changing the id length + id....
    
    	// in the meantime we overload the version byte to have a version number and flags
    	// flags = top 4 bits, version = bottom 4 bits
    
    byte version_and_flags = stream_payload.get( bss );
    
    byte version = (byte)( version_and_flags & 0x0f );
    
    if ( version >= MESSAGE_VERSION_SUPPORTS_PADDING ){
    
    	byte	flags =  (byte)(( version_and_flags >> 4 ) & 0x0f );
    	
    	if ( ( flags & 0x01 ) != 0 ){
    		
    		short padding_length = stream_payload.getShort( bss );
    	
    		byte[]	padding = new byte[padding_length];
    	
    		stream_payload.get( bss, padding );
    	}
    }
    
    return MessageManager.getSingleton().createMessage( id_bytes, stream_payload, version );
public static com.aelitis.azureus.core.networkmanager.RawMessagecreateAZRawMessage(Message base_message, boolean enable_padding)
Create the proper AZ raw message from the given base message.

param
base_message to create from
return
AZ raw message

    byte[] id_bytes = base_message.getIDBytes();
    byte version = base_message.getVersion();
    
    DirectByteBuffer[] payload = base_message.getData();
    
    int payload_size = 0;
    for( int i=0; i < payload.length; i++ ) {
      payload_size += payload[i].remaining( bss );
    }
       
    //create and fill header buffer
    
    DirectByteBuffer header;
    
    if ( version >= MESSAGE_VERSION_SUPPORTS_PADDING ){
    	    	
    	short 	padding_length = enable_padding?(short)(( Math.random() * ( payload_size>256?SMALL_PAD_MAX:BIG_PAD_MAX ))+1):0;
    	    	
    	byte	flags = enable_padding?(byte)0x01:(byte)0x00;
    	
    	int	header_size = 4 + 4 + id_bytes.length + 1 + (enable_padding?(2+padding_length):0);
    	
        header = DirectByteBufferPool.getBuffer( DirectByteBuffer.AL_MSG_AZ_HEADER, header_size );
        
	    header.putInt( bss, header_size - 4 + payload_size );
	    header.putInt( bss, id_bytes.length );
	    header.put( bss, id_bytes );
	    
	    byte version_and_flags = (byte)( ( flags << 4 ) | version );
	    
	    header.put( bss, version_and_flags ); 
	    
	    if ( enable_padding ){
	    	
	    	byte[]	padding = new byte[padding_length];
	    	
	    	header.putShort( bss, padding_length );
	    	header.put( bss, padding );
	    }
    }else{
    	
	   	int	header_size = 4 + 4 + id_bytes.length + 1;

	    header = DirectByteBufferPool.getBuffer( DirectByteBuffer.AL_MSG_AZ_HEADER, header_size );
	    
	    header.putInt( bss, header_size - 4 + payload_size );
	    header.putInt( bss, id_bytes.length );
	    header.put( bss, id_bytes );
	    header.put( bss, version ); 
    }
    
    header.flip( bss );
    
    DirectByteBuffer[] raw_buffs = new DirectByteBuffer[ payload.length + 1 ];
    raw_buffs[0] = header;
    for( int i=0; i < payload.length; i++ ) {
      raw_buffs[i+1] = payload[i];
    }
     
    String message_id = base_message.getID();
    
    LegacyData ld = (LegacyData)legacy_data.get( message_id );  //determine if a legacy BT message
    
    if( ld != null ) {  //legacy message, use pre-configured values
      return new RawMessageImpl( base_message, raw_buffs, ld.priority, ld.is_no_delay, ld.to_remove );
    }
    
    	// these should really be properties of the message...
    
    int 	priority;
    boolean	no_delay	= true;
    
    if ( message_id == AZMessage.ID_AZ_HANDSHAKE ){
    	
    		// handshake needs to go out first - if not high then bitfield can get in front of it...
    	
    	priority = RawMessage.PRIORITY_HIGH;
    	
    }else if ( message_id == AZMessage.ID_AZ_HAVE ){
    	
    	priority 	= RawMessage.PRIORITY_LOW;
    	no_delay	= false;
    	
    }else{
    	
    	   //standard message, ensure that protocol messages have wire priority over data payload messages

    	priority = base_message.getType() == Message.TYPE_DATA_PAYLOAD ? RawMessage.PRIORITY_LOW : RawMessage.PRIORITY_NORMAL;
    }
        
    return new RawMessageImpl( base_message, raw_buffs, priority, no_delay, null );
public static voidinit()
Initialize the factory, i.e. register the messages with the message manager.

   
    legacy_data.put( BTMessage.ID_BT_CHOKE, new LegacyData( RawMessage.PRIORITY_HIGH, true, new Message[]{new BTUnchoke((byte)0), new BTPiece(-1, -1, null,(byte)0 )} ) );
    legacy_data.put( BTMessage.ID_BT_UNCHOKE, new LegacyData( RawMessage.PRIORITY_NORMAL, true, new Message[]{new BTChoke((byte)0)} ) );
    legacy_data.put( BTMessage.ID_BT_INTERESTED, new LegacyData( RawMessage.PRIORITY_HIGH, true, new Message[]{new BTUninterested((byte)0)} ) );
    legacy_data.put( BTMessage.ID_BT_UNINTERESTED, new LegacyData( RawMessage.PRIORITY_NORMAL, false, new Message[]{new BTInterested((byte)0)} ) );
    legacy_data.put( BTMessage.ID_BT_HAVE, new LegacyData( RawMessage.PRIORITY_LOW, false, null ) );
    legacy_data.put( BTMessage.ID_BT_BITFIELD, new LegacyData( RawMessage.PRIORITY_HIGH, true, null ) );
    legacy_data.put( BTMessage.ID_BT_REQUEST, new LegacyData( RawMessage.PRIORITY_NORMAL, true, null ) );
    legacy_data.put( BTMessage.ID_BT_PIECE, new LegacyData( RawMessage.PRIORITY_LOW, false, null ) );
    legacy_data.put( BTMessage.ID_BT_CANCEL, new LegacyData( RawMessage.PRIORITY_HIGH, true, null ) );
    legacy_data.put( BTMessage.ID_BT_HANDSHAKE, new LegacyData( RawMessage.PRIORITY_HIGH, true, null ) );
    legacy_data.put( BTMessage.ID_BT_KEEP_ALIVE, new LegacyData( RawMessage.PRIORITY_LOW, false, null ) );
    legacy_data.put( BTMessage.ID_BT_LT_EXTENSION_HANDSHAKE, new LegacyData (RawMessage.PRIORITY_HIGH, false, null));
  
    try {
      MessageManager.getSingleton().registerMessageType( new AZHandshake( new byte[20], "", "", 0, 0, 0, new String[0], new byte[0], 0, MESSAGE_VERSION_SUPPORTS_PADDING ) );
      MessageManager.getSingleton().registerMessageType( new AZPeerExchange( new byte[20], null, null, MESSAGE_VERSION_SUPPORTS_PADDING ));
      MessageManager.getSingleton().registerMessageType( new AZRequestHint( -1, -1, -1, -1, MESSAGE_VERSION_SUPPORTS_PADDING ));
      MessageManager.getSingleton().registerMessageType( new AZHave( new int[0], MESSAGE_VERSION_SUPPORTS_PADDING ));
      MessageManager.getSingleton().registerMessageType( new AZBadPiece( -1, MESSAGE_VERSION_SUPPORTS_PADDING ));

      /*
      MessageManager.getSingleton().registerMessageType( new AZSessionSyn( new byte[20], -1, null) );
      MessageManager.getSingleton().registerMessageType( new AZSessionAck( new byte[20], -1, null) );
      MessageManager.getSingleton().registerMessageType( new AZSessionEnd( new byte[20], "" ) );
      MessageManager.getSingleton().registerMessageType( new AZSessionBitfield( -1, null ) );
      MessageManager.getSingleton().registerMessageType( new AZSessionCancel( -1, -1, -1, -1 ) );
      MessageManager.getSingleton().registerMessageType( new AZSessionHave( -1, new int[]{-1} ) );
      MessageManager.getSingleton().registerMessageType( new AZSessionPiece( -1, -1, -1, null ) );
      MessageManager.getSingleton().registerMessageType( new AZSessionRequest( -1, (byte)-1, -1, -1, -1 ) );
      */
    }
    catch( MessageException me ) {  me.printStackTrace();  }
public static voidregisterGenericMapPayloadMessageType(java.lang.String type_id)
Register a generic map payload type with the factory.

param
type_id to register
throws
MessageException on registration error

  	MessageManager.getSingleton().registerMessageType( new AZGenericMapPayload( type_id, null, MESSAGE_VERSION_INITIAL ) );