com.hazelcast.nio

Class PacketIOHelper

java.lang.Object

com.hazelcast.nio.PacketIOHelper

@PrivateApi
public class PacketIOHelper
extends Object

Responsible for writing or reading an Packet. Originally the logic was placed in the Packet. The problem with this approach is that a single Packet instance can't be shared between multiple connections and this leads to increased memory usage since the packet needs to be copied for every connection. The PacketIOHelper is stateful because it tracks where the packet reading from ByteBuffer or writing to ByteBuffer. A PacketIOHelper instance should only be used for reading, or only be used for writing. So if you need to read and write at the same time, you need to have 2 instances. A PacketIOHelper is designed to be reused.

Constructor Summary

Constructors

Constructor and Description
PacketIOHelper()

Method Summary

Modifier and Type	Method and Description
Packet	readFrom(ByteBuffer src) Reads the packet data from the supplied ByteBuffer.
boolean	writeTo(Packet packet, ByteBuffer dst) Writes the packet data to the supplied ByteBuffer, up to the buffer's limit.

Methods inherited from class java.lang.Object

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

Constructor Detail

PacketIOHelper

public PacketIOHelper()

Method Detail

writeTo

public boolean writeTo(Packet packet,
                       ByteBuffer dst)

Writes the packet data to the supplied ByteBuffer, up to the buffer's limit. If it returns false, it should be called again to write the remaining data.

Parameters:

dst - the destination byte buffer

Returns:

true if all the packet's data is now written out; false otherwise.

readFrom

public Packet readFrom(ByteBuffer src)

Reads the packet data from the supplied ByteBuffer. The buffer may not contain the complete packet. If this method returns false, it should be called again to read more packet data.

Parameters:

src - the source byte buffer

Returns:

the read Packet if all the packet's data is now read; null otherwise.