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

}