Package org.jcsp.lang

Class PoisonableOne2OneChannelIntImpl

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private Alternative alt
      The Alternative class that controls the selection
      private boolean done
      This flag indicates that the last transfer went OK.
      private boolean empty
      The synchronisation flag
      private int hold
      The (invisible-to-users) buffer used to store the data for the channel
      private int immunity
      Immunity is passed to the channel-ends, and is not used directly by the channel algorithms
      private int poisonStrength
      0 means unpoisoned
      private java.lang.Object rwMonitor
      The monitor synchronising reader and writer on this channel
      private boolean spuriousWakeUp
      Flag to deal with a spurious wakeup during a write
    • Field Detail

      • rwMonitor

        private java.lang.Object rwMonitor
        The monitor synchronising reader and writer on this channel
      • hold

        private int hold
        The (invisible-to-users) buffer used to store the data for the channel
      • empty

        private boolean empty
        The synchronisation flag
      • done

        private boolean done
        This flag indicates that the last transfer went OK. The purpose is to not throw a PoisonException to the writer side when the last transfer went OK, but the reader side injected poison before the writer side finished processing of the last write transfer.
      • poisonStrength

        private int poisonStrength
        0 means unpoisoned
      • immunity

        private int immunity
        Immunity is passed to the channel-ends, and is not used directly by the channel algorithms
      • alt

        private Alternative alt
        The Alternative class that controls the selection
      • spuriousWakeUp

        private boolean spuriousWakeUp
        Flag to deal with a spurious wakeup during a write
    • Constructor Detail

      • PoisonableOne2OneChannelIntImpl

        PoisonableOne2OneChannelIntImpl​(int _immunity)
    • Method Detail

      • isPoisoned

        private boolean isPoisoned()
      • in

        public AltingChannelInputInt in()
        Returns the AltingChannelInput to use for this channel. As One2OneChannelImpl implements AltingChannelInput itself, this method simply returns a reference to the object that it is called on.
        Specified by:
        in in interface One2OneChannelInt
        Returns:
        the AltingChannelInput object to use for this channel.
      • out

        public ChannelOutputInt out()
        Returns the ChannelOutput object to use for this channel. As One2OneChannelImpl implements ChannelOutput itself, this method simply returns a reference to the object that it is called on.
        Specified by:
        out in interface One2OneChannelInt
        Returns:
        the ChannelOutput object to use for this channel.
      • write

        public void write​(int value)
        Writes an Object to the channel.
        Specified by:
        write in interface ChannelInternalsInt
        Parameters:
        value - the object to write to the channel.
      • read

        public int read()
        Reads an Object from the channel.
        Specified by:
        read in interface ChannelInternalsInt
        Returns:
        the object read from the channel.
      • readerEnable

        public boolean readerEnable​(Alternative alt)
        turns on Alternative selection for the channel. Returns true if the channel has data that can be read immediately.

        Note: this method should only be called by the Alternative class

        Specified by:
        readerEnable in interface ChannelInternalsInt
        Parameters:
        alt - the Alternative class which will control the selection
        Returns:
        true if the channel has data that can be read, else false
      • readerDisable

        public boolean readerDisable()
        turns off Alternative selection for the channel. Returns true if the channel contained data that can be read.

        Note: this method should only be called by the Alternative class

        Specified by:
        readerDisable in interface ChannelInternalsInt
        Returns:
        true if the channel has data that can be read, else false
      • readerPending

        public boolean readerPending()
        Returns whether there is data pending on this channel.

        Note: if there is, it won't go away until you read it. But if there isn't, there may be some by the time you check the result of this method.

        This method is provided for convenience. Its functionality can be provided by Pri Alting the channel against a SKIP guard, although at greater run-time and syntactic cost. For example, the following code fragment:

           if (c.pending ()) {
             Object x = c.read ();
             ...  do something with x
           } else (
             ...  do something else
           }
         
        is equivalent to:
           if (c_pending.priSelect () == 0) {
             Object x = c.read ();
             ...  do something with x
           } else (
             ...  do something else
         }
         
        where earlier would have had to have been declared:
         final Alternative c_pending =
           new Alternative (new Guard[] {c, new Skip ()});
         
        Specified by:
        readerPending in interface ChannelInternalsInt
        Returns:
        state of the channel.