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/*
    GNU LESSER GENERAL PUBLIC LICENSE
    Copyright (C) 2006 The Lobo Project

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Contact info: [email protected]
 */
/*
 * Created on Mar 19, 2005
 */
package org.cobraparser.util;

import java.util.ArrayList;
import java.util.Collection;
import java.util.EventListener;
import java.util.EventObject;

/**
 * @author J. H. S.
 */
public abstract class EventDispatch2 {
  private Collection listeners;
  private static final EventListener[] EMPTY_ARRAY = new EventListener[0];

  public EventDispatch2() {
  }

  public Collection createListenerCollection() {
    return new ArrayList<>();
  }

  public final void addListener(final EventListener listener) {
    synchronized (this) {
      if (this.listeners == null) {
        this.listeners = this.createListenerCollection();
      }
      this.listeners.add(listener);
    }
  }

  public final void removeListener(final EventListener listener) {
    synchronized (this) {
      if (this.listeners != null) {
        this.listeners.remove(listener);
      }
    }
  }

  public final boolean fireEvent(final EventObject event) {
    EventListener[] larray;
    synchronized (this) {
      final Collection listeners = this.listeners;
      if ((listeners == null) || (listeners.size() == 0)) {
        return false;
      }
      larray = this.listeners.toArray(EMPTY_ARRAY);
    }
    final int length = larray.length;
    for (int i = 0; i < length; i++) {
      // Call holding no locks
      this.dispatchEvent(larray[i], event);
    }
    return true;
  }

  protected abstract void dispatchEvent(EventListener listener, EventObject event);
}