Class ActionSelector


  • class ActionSelector
    extends java.lang.Object
    The ActionSelector object is used to perform socket based selection with the help of the ActionSet object. All registered channels have an associated action set. The action set contains a set of actions that should be executed when the selector selects the channel.
    • Field Summary

      Fields 
      Modifier and Type Field Description
      private java.nio.channels.Selector selector
      This is the selector used to perform the select operations.
    • Constructor Summary

      Constructors 
      Constructor Description
      ActionSelector()
      Constructor for the ActionSelector object.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void close()
      This is used to close the associated selector.
      ActionSet register​(java.nio.channels.SelectableChannel channel, int interest)
      This performs the actual registration of the channel for selection based on the provided interest bitmask.
      java.util.List<ActionSet> registeredSets()
      This is used to acquire all the action sets that are associated with this selector.
      private java.util.List<ActionSet> registeredSets​(java.util.Iterator<java.nio.channels.SelectionKey> keys)
      This is used to acquire all the action sets that are associated with this selector.
      int select​(long timeout)
      This is used to perform a select on the selector.
      java.util.List<ActionSet> selectedSets()
      This is used to acquire all the action sets that are selected by this selector.
      private java.util.List<ActionSet> selectedSets​(java.util.Iterator<java.nio.channels.SelectionKey> keys)
      This is used to acquire all the action sets that are selected by this selector.
      void wake()
      This is used to wake the selector if it is in the middle of a select operation.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Field Detail

      • selector

        private final java.nio.channels.Selector selector
        This is the selector used to perform the select operations.
    • Constructor Detail

      • ActionSelector

        public ActionSelector()
                       throws java.io.IOException
        Constructor for the ActionSelector object. This is used to create a selector that can register socket channels with an associated ActionSet. The set can then be used to store actions to be executed upon selection.
        Throws:
        java.io.IOException
    • Method Detail

      • select

        public int select​(long timeout)
                   throws java.io.IOException
        This is used to perform a select on the selector. This returns the number of channels that have been selected. If this returns a number greater than zero the ready method can be used to acquire the actions that are ready for execution.
        Parameters:
        timeout - this is the timeout associated with the select
        Returns:
        this returns the number of channels that are ready
        Throws:
        java.io.IOException
      • register

        public ActionSet register​(java.nio.channels.SelectableChannel channel,
                                  int interest)
                           throws java.io.IOException
        This performs the actual registration of the channel for selection based on the provided interest bitmask. When the channel has been registered for selection this returns an ActionSet for the selection key. The set can then be used to register the actions that should be executed when selection succeeds.
        Parameters:
        channel - this is the channel to register for selection
        interest - this is the interested operations bitmask
        Returns:
        this is the action set associated with the registration
        Throws:
        java.io.IOException
      • registeredSets

        public java.util.List<ActionSet> registeredSets()
        This is used to acquire all the action sets that are associated with this selector. Only action sets that have a valid selection key are returned. Modification of the list will not affect the associated selector instance.
        Returns:
        this returns all the associated action sets for this
      • registeredSets

        private java.util.List<ActionSet> registeredSets​(java.util.Iterator<java.nio.channels.SelectionKey> keys)
        This is used to acquire all the action sets that are associated with this selector. Only action sets that have a valid selection key are returned. Modification of the list will not affect the associated selector instance.
        Parameters:
        keys - the selection keys to get the associated sets from
        Returns:
        this returns all the associated action sets for this
      • selectedSets

        public java.util.List<ActionSet> selectedSets()
                                               throws java.io.IOException
        This is used to acquire all the action sets that are selected by this selector. All action sets returned are unregistered from the selector and must be registered again to hear about further I/O events that occur on the associated channel.
        Returns:
        this returns all the selected action sets for this
        Throws:
        java.io.IOException
      • selectedSets

        private java.util.List<ActionSet> selectedSets​(java.util.Iterator<java.nio.channels.SelectionKey> keys)
        This is used to acquire all the action sets that are selected by this selector. All action sets returned are unregistered from the selector and must be registered again to hear about further I/O events that occur on the associated channel.
        Parameters:
        keys - the selection keys to get the associated sets from
        Returns:
        this returns all the selected action sets for this
      • wake

        public void wake()
                  throws java.io.IOException
        This is used to wake the selector if it is in the middle of a select operation. Waking up the selector in this manner is useful if further actions are to be registered with it.
        Throws:
        java.io.IOException
      • close

        public void close()
                   throws java.io.IOException
        This is used to close the associated selector. Further attempts to register a channel with the selector will fail. All actions should be cancelled before closing the selector in this way.
        Throws:
        java.io.IOException