/*
 * Copyright 2012  Research Studios Austria Forschungsges.m.b.H.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */

package won.bot.framework.eventbot.filter.impl;

import won.bot.framework.eventbot.event.Event;
import won.bot.framework.eventbot.filter.AbstractDelegatingFilter;
import won.bot.framework.eventbot.filter.EventFilter;

/**
 * Delegating filter that counts how many times its delegate has accepted. Will only accept a given number of times.
 */
public class AcceptNTimesFilter extends AbstractDelegatingFilter
{
  private int count = 0;
  private int targetCount = 0;

  public AcceptNTimesFilter(final EventFilter delegate, final int targetCount)
  {
    super(delegate);
    this.targetCount = targetCount;
  }

  @Override
  public boolean accept(final Event event)
  {
    boolean delegateAccepts = getDelegate().accept(event);
    if (!delegateAccepts) return false;
    synchronized (this) {
      if (count < targetCount) {
        count ++;
        return true;
      }
    }
    return false;
  }
}