We distinguish two Channel components : ChannelIn and ChannelOut.

• ChannelIn are used to received messages from other address space.
• ChannelOut are used to send mesage to other address space.

This package contains various Channel implementationx. They are based on an abstraction of a socket. A socket provides an input, an output and a method to close it (see {@link org.objectweb.dream.channel.SocketState} interface).

Channel components use {@link org.objectweb.dream.message.codec.MessageCodec} interface to encode and decode message using input or output provided by a socket.

Channel components are composite components build as following :

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PushChannelOut are composed by :

• GenericPushChannelOut component (implemented by {@link org.objectweb.dream.channel.GenericPushChannelOutImpl}). When this component receive a message on its {@link org.objectweb.dream.Push} interface, it use a {@link org.objectweb.dream.channel.SocketManager} to retrieve a socket to send the message. Then it use a {@link org.objectweb.dream.message.codec.MessageCodec} to encode the message. Finally, if the component is bound to a component providing a {@link org.objectweb.dream.channel.WaitByte} interface, it wait for an acknowledgement.
• SocketManager components. These components are responsible to give {@link org.objectweb.dream.channel.SocketState} to GenericPushChannelOut component. Their role is to choose a ChannelIn for each message, then to find a socket to send this message to the chosen ChannelIn.
  These two steps are acheived by differents components. Fisrts ones identify a ChannelIn, seconds ones find the socket.
  The identification of a ChannelIn depends on the socket implementation. For example, TCP Channels use an inet adresse and a port to identify a ChannelIn. So components responsible to find a socket provide the {@link org.objectweb.dream.channel.IPSocketManager} interface (see {@link org.objectweb.dream.channel.IPSocketManagerTCPImpl} component).
  Provided SocketManager components are the following :
  • {@link org.objectweb.dream.channel.SocketManagerIPStaticImpl} identify staticaly a ChannelIn using its attribute controller interface ({@link org.objectweb.dream.channel.SocketManagerIPStaticAttributeController}).
  • {@link org.objectweb.dream.channel.SocketManagerIPChunkBasedImpl} identify a ChannelIn by retrieving a {@link org.objectweb.dream.channel.IPChannelDestinationChunk} chunk in each message. The name of the chunk can be configured using the attribute controller interface ({@link org.objectweb.dream.channel.SocketManagerIPChunkBasedAttributeController}).
  • {@link org.objectweb.dream.channel.IPSocketManagerTCPImpl} create socket using given inet address and port. The release method simply close the socket state.
  • {@link org.objectweb.dream.channel.IPSocketManagerCachingImpl} manage a cache of socket. If the asked socket can't be found in the cache or is closed, this component delegate to a client IPSocketManager. The cache size can be configured using the attribute controller.
    If a socket is asked two time before being released, an exception is thrown.
• An optional WaitAck component used to wait an acknowledgment on the input of the socket used to send the message. If the byte received is not null, an exception is thrown.

PushChannelIn are composed by :

• GenericPushChannelIn component (implemented by {@link org.objectweb.dream.channel.GeneriquePushChannelIn}). When this component receive a socket on its {@link org.objectweb.dream.channel.OpenedSocket} interface, it use a {@link org.objectweb.dream.message.codec.MessageCodec} to decode an incomming message. Then, if the component is bound to a component providing a {@link org.objectweb.dream.channel.SendByte} interface, it send an acknowledgement.
• OpenedSocketManager components. These components are responsible to give {@link org.objectweb.dream.channel.SocketState} to GenericPushChannelIn component to read message from.