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