Package org.jgroups.protocols

Class COMPRESS

  • public class COMPRESS
extends Protocol
    Compresses the payload of a message. Goal is to reduce the number of messages sent across the wire. Should ideally be layered somewhere above a fragmentation protocol (e.g. FRAG).
    Author:
    Bela Ban

    • Field Detail

      • compression_level

        protected int compression_level

      • min_size

        protected long min_size

      • pool_size

        protected int pool_size

      • deflater_pool

        protected java.util.concurrent.BlockingQueue<java.util.zip.Deflater> deflater_pool

      • inflater_pool

        protected java.util.concurrent.BlockingQueue<java.util.zip.Inflater> inflater_pool

    • Constructor Detail

      • COMPRESS

        public COMPRESS()

    • Method Detail

      • init

        public void init()
          throws java.lang.Exception
        Description copied from class: Protocol
        Called after instance has been created (null constructor) and before protocol is started. Properties are already set. Other protocols are not yet connected and events cannot yet be sent.
        Overrides:
        init in class Protocol
        Throws:
        java.lang.Exception - Thrown if protocol cannot be initialized successfully. This will cause the ProtocolStack to fail, so the channel constructor will throw an exception

      • destroy

        public void destroy()
        Description copied from class: Protocol
        This method is called on a JChannel.close(). Does some cleanup; after the call the VM will terminate
        Overrides:
        destroy in class Protocol

      • down

        public java.lang.Object down​(Message msg)
        We compress the payload if it is larger than min_size. In this case we add a header containing the original size before compression. Otherwise we add no header.

        Note that we compress either the entire buffer (if offset/length are not used), or a subset (if offset/length are used)

        Overrides:
        down in class Protocol

      • up

        public java.lang.Object up​(Message msg)
        If there is no header, we pass the message up. Otherwise we uncompress the payload to its original size.
        Overrides:
        up in class Protocol

      • up

        public void up​(MessageBatch batch)
        Description copied from class: Protocol
        Sends up a multiple messages in a MessageBatch. The sender of the batch is always the same, and so is the destination (null == multicast messages). Messages in a batch can be OOB messages, regular messages, or mixed messages, although the transport itself will create initial MessageBatches that contain only either OOB or regular messages.

        The default processing below sends messages up the stack individually, based on a matching criteria (calling Protocol.accept(org.jgroups.Message)), and - if true - calls Protocol.up(org.jgroups.Event) for that message and removes the message. If the batch is not empty, it is passed up, or else it is dropped.

        Subclasses should check if there are any messages destined for them (e.g. using MessageBatch.getMatchingMessages(short,boolean)), then possibly remove and process them and finally pass the batch up to the next protocol. Protocols can also modify messages in place, e.g. ENCRYPT could decrypt all encrypted messages in the batch, not remove them, and pass the batch up when done.

        Overrides:
        up in class Protocol
        Parameters:
        batch - The message batch

      • uncompress

        protected Message uncompress​(Message msg,
                             int original_size)
        Returns a new message as a result of uncompressing msg, or null if msg couldn't be uncompressed