package org.apidesign.openfixed;

 import java.util.List;

 import java.util.concurrent.CopyOnWriteArrayList;

 import java.util.concurrent.Executor;

 import java.util.concurrent.Executors;

 import org.apidesign.openfixed.Calculator.EventSupport;

 /**

  *

  * @author Jaroslav Tulach <jtulach@netbeans.org>

  */

 final class AsyncEventSupport implements EventSupport {

     private final List<ModificationListener> listeners = new CopyOnWriteArrayList<ModificationListener>();

     AsyncEventSupport() {

     }

     @Override

     public void add(ModificationListener l) {

         listeners.add(l);

     }

     @Override

     public void remove(ModificationListener l) {

         listeners.remove(l);

     }

     // BEGIN: openfixed.asynch

     private static final Executor EXEC = Executors.newSingleThreadExecutor();

     @Override

     public void fireModificationEvent(ModificationEvent ev) {

         EXEC.execute(new Deliverable(

             ev, listeners.toArray(new ModificationListener[0])

         ));

     }

     private static class Deliverable implements Runnable {

         final ModificationEvent ev;

         final ModificationListener[] listeners;

         public Deliverable(

             ModificationEvent ev, ModificationListener[] listeners

         ) {

             this.ev = ev;

             this.listeners = listeners;

         }

         @Override

         public void run() {

             for (ModificationListener l : listeners) {

                 l.modification(ev);

             }

         }

     }

     // END: openfixed.asynch

 }