package org.apidesign.openfixed;

 import java.util.HashSet;

 import java.util.List;

 import java.util.Set;

 import java.util.concurrent.CopyOnWriteArrayList;

 import java.util.concurrent.Executor;

 import java.util.concurrent.Executors;

 /**

  *

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

  */

 final class PostEventSupport implements EventSupport, Runnable {

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

     private final List<Deliverable> deliverables = new CopyOnWriteArrayList<Deliverable>();

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

     PostEventSupport() {

     }

     @Override

     public void fireModificationEvent(ModificationEvent ev) {

         synchronized (deliverables) {

             final Deliverable d = new Deliverable(ev, listeners.toArray(new ModificationListener[0]));

             deliverables.add(d);

             EXEC.execute(this);

         }

     }

     @Override

     public void add(ModificationListener l) {

         listeners.add(l);

     }

     @Override

     public void remove(ModificationListener l) {

         listeners.remove(l);

     }

     @Override

     public void run() {

         Deliverable[] pending;

         synchronized (deliverables) {

             if (deliverables.isEmpty()) {

                 return;

             }

             pending = deliverables.toArray(new Deliverable[0]);

             deliverables.clear();

         }

         Calculator calc = null;

         Set<PostModificationListener> notify = new HashSet<PostModificationListener>();

         int pendingCount = pending.length;

         for (Deliverable d : pending) {

             calc = (Calculator)d.ev.getSource();

             d.ev.pending = --pendingCount;

             d.ev.posts = notify;

             for (ModificationListener l : d.listeners) {

                 l.modification(d.ev);

             }

             d.ev.posts = null;

         }

         for (PostModificationListener pml : notify) {

             pml.postProcess(new PostModificationEvent(calc));

         }

     }

     private static class Deliverable {

         final ModificationEvent ev;

         final ModificationListener[] listeners;

         public Deliverable(ModificationEvent ev, ModificationListener[] listeners) {

             this.ev = ev;

             this.listeners = listeners;

         }

     }

 }