Package org.jcsp.net

Class One2NetChannel

    • Constructor Summary

      Constructors 
      Constructor Description
      One2NetChannel​(NetChannelLocation channelLocation)
      Constructor which takes the location of a Networked ChannelInput to which to send data.
      One2NetChannel​(NetChannelLocation channelLocation, boolean acknowledged)
      Constructor which takes the location of a Networked ChannelInput to which to send data and a boolean indicating whether or not to obtain acknowledgements.
      One2NetChannel​(NetChannelLocation channelLocation, boolean acknowledged, Profile linkProfile)
      Constructor which takes the location of a Networked ChannelInput to which to send data and a boolean indicating whether or not to obtain acknowledgements.
      One2NetChannel​(NetChannelLocation channelLocation, Profile linkProfile)
      Constructor which takes the location of a Networked ChannelInput to which to send data and a Profile that any Link used should match.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void destroyWriter()
      This destroys this write end of the channel and frees any resources in the JCSP.NET infrastructure.
      NetChannelLocation getChannelLocation()
      Returns a clone of the NetChannelLocation object held by the instance of this class which contains information about the location of the networked ChannelInput object to which this ChannelOutput is connected.
      java.lang.Class getFactoryClass()
      Returns the factory class used for constructing this channel end object.
      (package private) void linkFailed​(NodeID remoteID)  
      void poison​(int strength)
      Currently, network channels are unpoisonable so this method has no effect.
      private void readObject​(java.io.ObjectInputStream stream)
      Handles deserialization.
      void recreate()
      Requests that the channel recreates itself and reconnects to the other end of the channel.
      void recreate​(NetChannelLocation newLoc)
      Requests that the channel recreates itself and reconnects to the other end of the channel.
      void write​(java.lang.Object data)
      Output data to this channel.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • channelID

        private transient ChannelID channelID
        The channel ID of the remote computer. Not valid unless we are connected.

      • channelIndex

        private transient long channelIndex
        Our channel index. (On the local computer, for acknowlegements).

      • fromNetIn

        private transient AltingChannelInput fromNetIn
        The channel we use for recieving from the demuxes.

      • toNet

        private transient ChannelOutput toNet
        The channel we use for sending to the network TX. Not valid unless we are connected.

      • broken

        private transient boolean broken
        True iff the link's been dropped.

      • connected

        private transient boolean connected
        True iff we're connected to the remote computer.

      • sendMessageA

        private transient boolean sendMessageA

      • linkProfile

        private final Profile linkProfile
        The Profile that the link used by this channel should match.

      • maxUnacknowledged

        private final int maxUnacknowledged
        The maximum number of data items "in flight" when a call to write() returns. The default setting of zero gives standard unbuffered channel semantics. 5/Jun/2002 This is not currently used nor exposed to the user. Streaming has been changed so that acknowledgements are either on or off. Flow control really needs to be controlled from the receiving end but this functionality has not yet been implemented.

      • numUnacknowledged

        private transient int numUnacknowledged
        The number of data items currently unacknowledged ("in flight"). Always <= maxUnacknowledged + 1. If it is > maxUnacknowledged, then we must be blocked in write().

      • acknowledged

        private boolean acknowledged
        Indicates whether this channel requires acknowledgements to be returned from the receiver.

    • Constructor Detail

      • One2NetChannel

        public One2NetChannel​(NetChannelLocation channelLocation)
        Constructor which takes the location of a Networked ChannelInput to which to send data. The channel constructed will block after any data is sent until an acknowledgement is returned. A Link to the ChannelInput object's Node will be established if necessary. This Link may be established over any available protocol implementation. This constructor is equivalent to using the (NetChannelLocation, boolean, Profile) constructor with the boolean set to true and the Profile set to null.

      • One2NetChannel

        public One2NetChannel​(NetChannelLocation channelLocation,
                      Profile linkProfile)
        Constructor which takes the location of a Networked ChannelInput to which to send data and a Profile that any Link used should match. The channel constructed will block after any data is sent until an acknowledgement is returned. A Link to the ChannelInput object's Node will be established if necessary. This Link will match the specified Profile. A RuntimeException will be thrown if a a matching Link cannot be established. This constructor is equivalent to using the (NetChannelLocation, boolean, Profile) constructor with the boolean set to true.

      • One2NetChannel

        public One2NetChannel​(NetChannelLocation channelLocation,
                      boolean acknowledged)
        Constructor which takes the location of a Networked ChannelInput to which to send data and a boolean indicating whether or not to obtain acknowledgements. If the acknowledged parameter is true, then the channel constructed will block after any data is sent until an acknowledgement is returned. Otherwise, the channel should not block, however, some flow control may be implemented which may result in blocking. A Link to the ChannelInput object's Node will be established if necessary. This Link may be established over any available protocol implementation. This constructor is equivalent to using the (NetChannelLocation, boolean, Profile) constructor with the Profile set to null.

      • One2NetChannel

        public One2NetChannel​(NetChannelLocation channelLocation,
                      boolean acknowledged,
                      Profile linkProfile)
        Constructor which takes the location of a Networked ChannelInput to which to send data and a boolean indicating whether or not to obtain acknowledgements. If the acknowledged parameter is true, then the channel constructed will block after any data is sent until an acknowledgement is returned. Otherwise, the channel should not block, however, some flow control may be implemented which may result in blocking. A Link to the ChannelInput object's Node will be established if necessary. This Link will match the specified Profile. A RuntimeException will be thrown if a a matching Link cannot be established.

    • Method Detail

      • write

        public void write​(java.lang.Object data)
        Output data to this channel. The data must be Serializable.

        For a normal channel (numUnacknowledged == 0), the contract of this method is as follows: When the method returns, the data has been sent to the remote computer, and the process (or user-supplied buffer) at the other end has accepted it. It is safe to modify data after the call. Transmission is guaranteed unless a LinkLostException is thrown, in which case it is impossible to determine whether or not the remote computer recieved the data before the link dropped.

        For a streaming channel (numUnacknowledged > 0), the contract of this method is slightly different. When the method returns, the data has started it's trip to the remote computer, but the link may go down so there is no guarantee that it will get there. Also, since it may not have left this computer yet (the actual transmission is done in parallel with the return from this method), it is *NOT* safe to modify the passed data object. After the next call to this method, then you may assume that the data object has been transmitted, and re-use it or let the Java garbage collector deal with it as appropriate. You must wait a total of numUnacknowledged calls to this method before you can assume that the data was recieved - and if any of those calls throw a LinkLostException, then you cannot find out how much of the stream of data was recieved by the remote computer before the link broke.

        A LinkLostException is thrown if the TCP/IP link is dropped. This could be due to a network problem, but more often it is caused when the remote Java VM crashes or is shut down. It can also be caused if there is a serialization problem with the TCP/IP link - e.g. an attempt to send a non-serializable object, or an attempt to send a class which doesn't exist or isn't the same version at the recieving end. Note that LinkLostException is a permanent error - if it is thrown, then any further call to this method will cause it to be thrown again.

        Specified by:
        write in interface ChannelOutput
        Parameters:
        data - an object to send over the channel. This should be Serializable.

      • getChannelLocation

        public NetChannelLocation getChannelLocation()
        Returns a clone of the NetChannelLocation object held by the instance of this class which contains information about the location of the networked ChannelInput object to which this ChannelOutput is connected.
        Specified by:
        getChannelLocation in interface Networked
        Returns:
        the NetChannelLocation of the destination ChannelInput.

      • linkFailed

        void linkFailed​(NodeID remoteID)

      • destroyWriter

        public void destroyWriter()
        This destroys this write end of the channel and frees any resources in the JCSP.NET infrastructure.
        Specified by:
        destroyWriter in interface NetChannelOutput

      • recreate

        public void recreate()
        Requests that the channel recreates itself and reconnects to the other end of the channel. This method will call refresh() on the NetChannelLocation it holds for its destination. If the instance held is an instance of a sub-class of NetChannelLocation then this provides an oportunity for the instance to refresh its information. This could, for example, be from a naming service.
        Specified by:
        recreate in interface NetChannelOutput

      • recreate

        public void recreate​(NetChannelLocation newLoc)
        Requests that the channel recreates itself and reconnects to the other end of the channel. A new location of the read end can be supplied.
        Specified by:
        recreate in interface NetChannelOutput
        Parameters:
        newLoc - the new location of the read end of the channel.

      • getFactoryClass

        public java.lang.Class getFactoryClass()
        Description copied from interface: NetChannelOutput

        Returns the factory class used for constructing this channel end object.

        Specified by:
        getFactoryClass in interface NetChannelOutput
        Returns:
        the Class of the

      • poison

        public void poison​(int strength)
        Currently, network channels are unpoisonable so this method has no effect.
        Specified by:
        poison in interface Poisonable
        Parameters:
        strength - the strength of the poison (must be >= 0).

      • readObject

        private void readObject​(java.io.ObjectInputStream stream)
                 throws java.io.IOException,
                        java.lang.ClassNotFoundException
        Handles deserialization. This is responsible for starting up the process which handles output, and for creating the internal channel.
        Throws:
        java.io.IOException
        java.lang.ClassNotFoundException