package org.apidesign.openfixed;

 /** Sample bean using the {@link ModificationListener}

  * to <b>add</b> numbers.

  *

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

  */

 // BEGIN: openfixed.bean

 public final class Calculator {

     private final EventSupport listeners;

     private int sum;

     private Calculator(EventSupport listeners) {

         this.listeners = listeners;

     }

     /** An abstraction over various types of event delivery

      * to listeners. Comes with four different implementations.

      * A trivial one, asynchronous one, one with support for

      * pending events and one for a batch events delivery.

      */

     interface EventSupport {

         public void fireModificationEvent(ModificationEvent ev);

         public void add(ModificationListener l);

         public void remove(ModificationListener l);

     }

     public static Calculator create() {

         return new Calculator(new TrivialEventSupport());

     }

     public static Calculator createAsynch() {

         return new Calculator(new AsyncEventSupport());

     }

     /** @since 2.0 */

     public static Calculator createPending() {

         return new Calculator(new PendingEventSupport());

     }

     /** @since 3.0 */

     public static Calculator createBatch() {

         return new Calculator(new PostEventSupport());

     }

     public synchronized void add(int add) {

         sum += add;

         listeners.fireModificationEvent(new ModificationEvent(this, add));

     }

     public synchronized int getSum() {

         return sum;

     }

     public void addModificationListener(ModificationListener l) {

         listeners.add(l);

     }

     public void removeModificationListener(ModificationListener l) {

         listeners.remove(l);

     }

 }

 // END: openfixed.bean