com.google.bitcoin.net
Class ProtobufParser<MessageType extends com.google.protobuf.MessageLite>

java.lang.Object
  com.google.bitcoin.net.AbstractTimeoutHandler
      com.google.bitcoin.net.ProtobufParser<MessageType>

All Implemented Interfaces:

StreamParser

public class ProtobufParser<MessageType extends com.google.protobuf.MessageLite>
extends AbstractTimeoutHandler
implements StreamParser

A handler which is used in NioServer and NioClient to split up incoming data streams into protobufs and provide an interface for writing protobufs to the connections.

Messages are encoded with a 4-byte signed integer (big endian) prefix to indicate their length followed by the serialized protobuf

Nested Class Summary

static interface

ProtobufParser.Listener<MessageType extends com.google.protobuf.MessageLite> An interface which can be implemented to handle callbacks as new messages are generated and socket events occur.

Constructor Summary

ProtobufParser(ProtobufParser.Listener<MessageType> handler, MessageType prototype, int maxMessageSize, int timeoutMillis)
Creates a new protobuf handler.

Method Summary

void	closeConnection() Closes this connection, eventually triggering a connectionClosed() event.
void	connectionClosed() Called when the connection socket is closed
void	connectionOpened() Called when the connection socket is first opened
int	getMaxMessageSize() Returns the maximum message size of a message on the socket.
int	receiveBytes(ByteBuffer buff) Called when new bytes are available from the remote end.
void	setWriteTarget(MessageWriteTarget writeTarget) Called when this parser is attached to an upstream write target (ie a low-level connection handler).
protected void	timeoutOccurred()
void	write(MessageType msg) Writes the given message to the other side of the connection, prefixing it with the proper 4-byte prefix.

Methods inherited from class com.google.bitcoin.net.AbstractTimeoutHandler

resetTimeout, setSocketTimeout, setTimeoutEnabled

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ProtobufParser

public ProtobufParser(ProtobufParser.Listener<MessageType> handler,
                      MessageType prototype,
                      int maxMessageSize,
                      int timeoutMillis)

Creates a new protobuf handler.

Parameters:

handler - The callback listener

prototype - The default instance of the message type used in both directions of this channel. This should be the return value from MessageType#getDefaultInstanceForType()

maxMessageSize - The maximum message size (not including the 4-byte length prefix). Note that this has an upper bound of Integer.MAX_VALUE - 4

timeoutMillis - The timeout between messages before the connection is automatically closed. Only enabled after the connection is established.

Method Detail

setWriteTarget

public void setWriteTarget(MessageWriteTarget writeTarget)

Description copied from interface: StreamParser

Called when this parser is attached to an upstream write target (ie a low-level connection handler). This writeTarget should be stored and used to close the connection or write data to the socket.

Specified by:

setWriteTarget in interface StreamParser

getMaxMessageSize

public int getMaxMessageSize()

Description copied from interface: StreamParser

Returns the maximum message size of a message on the socket. This is used in calculating size of buffers to allocate.

Specified by:

getMaxMessageSize in interface StreamParser

closeConnection

public void closeConnection()

Closes this connection, eventually triggering a connectionClosed() event.

timeoutOccurred

protected void timeoutOccurred()

Specified by:

timeoutOccurred in class AbstractTimeoutHandler

receiveBytes

public int receiveBytes(ByteBuffer buff)
                 throws Exception

Description copied from interface: StreamParser

Called when new bytes are available from the remote end. This should only ever be called by the single writeTarget associated with any given StreamParser, multiple callers will likely confuse implementations.

Implementers/callers must follow the following conventions exactly:

• buff will start with its limit set to the position we can read to and its position set to the location we will start reading at (always 0)
• May read more than one message (recursively) if there are enough bytes available
• Uses some internal buffering to store message which are larger (incl their length prefix) than buff's capacity(), ie it is up to this method to ensure we dont run out of buffer space to decode the next message.
• buff will end with its limit the same as it was previously, and its position set to the position up to which bytes have been read (the same as its return value)
• buff must be at least the size of a Bitcoin header (incl magic bytes).

Specified by:

receiveBytes in interface StreamParser

Returns:

The amount of bytes consumed which should not be provided again

Throws:

Exception

connectionClosed

public void connectionClosed()

Description copied from interface: StreamParser

Called when the connection socket is closed

Specified by:

connectionClosed in interface StreamParser

connectionOpened

public void connectionOpened()

Description copied from interface: StreamParser

Called when the connection socket is first opened

Specified by:

connectionOpened in interface StreamParser

write

public void write(MessageType msg)
           throws IllegalStateException

Writes the given message to the other side of the connection, prefixing it with the proper 4-byte prefix.

Provides a write-order guarantee.

Throws:

IllegalStateException - If the encoded message is larger than the maximum message size.