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 package com.sun.grizzly.suspendable;

 import java.nio.channels.SelectionKey;

 /**

  * An Object representing the result of an suspendable operation like {@link SuspendableFilter@#suspend}

  * An instance of that class can be used to resume or cancel a suspended connection.

  * See {@link SuspendableFilter} for more information.

  * 

  * @author Jeanfrancois Arcand

  */

 public class Suspendable {

     private SuspendableFilter suspendableFilter;

     private SelectionKey key;

     private boolean isResumed = false;

     protected Suspendable(SuspendableFilter suspendableFilter) {

         this.suspendableFilter = suspendableFilter;

     }

     /**

      * Resume a suspended connection. If the connection has been resumed, calling

      * resume with produce an {@link IllegalStateException}.

      * @return true is resumed.

      */

     public boolean resume() {

         if (getKey() == null){

             isResumed = true;

             return isResumed;

         }

         isResumed = suspendableFilter.resume(getKey());

         return isResumed;

     }

     /**

      * Return true if the connection associated with this instance has been {@link #resumed}

      * 

      * @return true if resumed.

      */

     public boolean isResumed() {

         return isResumed;

     }

     /**

      * Cancel a suspended connection. If the connection has been  {@link #resumed}, calling

      * resume with produce an {@link IllegalStateException}.

      * @return true is resumed.

      */

     public void cancel(){

         if (isResumed) {

             throw new IllegalStateException("Already cancelled");

         }

         if (getKey() == null){

             isResumed = true;

             return;

         }

         suspendableFilter.cancel(getKey());

     }

     /**

      * Return the underlying SelectionKey representing the connection.

      * @return the underlying SelectionKey representing the connection.

      */

     protected SelectionKey getKey() {

         return key;

     }

     /**

      * Set the underlying SelectionKey.

      * @param key  the underlying SelectionKey.

      */

     protected void setKey(SelectionKey key) {

         this.key = key;

     }

 }