/*
 * The JTS Topology Suite is a collection of Java classes that
 * implement the fundamental operations required to validate a given
 * geo-spatial data set to a known topological specification.
 *
 * Copyright (C) 2001 Vivid Solutions
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * For more information, contact:
 *
 *     Vivid Solutions
 *     Suite #1A
 *     2328 Government Street
 *     Victoria BC  V8T 5G5
 *     Canada
 *
 *     (250)385-6040
 *     www.vividsolutions.com
 */
package com.revolsys.geometry.util;

import java.util.HashMap;
import java.util.Map;

/**
 * Counts occurences of objects.
 *
 * @author Martin Davis
 *
 */
public class ObjectCounter {

  private static class Counter {
    int count = 0;

    public Counter(final int count) {
      this.count = count;
    }

    public int count() {
      return this.count;
    }

    public void increment() {
      this.count++;
    }
  }

  private final Map counts = new HashMap();

  public ObjectCounter() {
  }

  // TODO: add remove(Object o)

  public void add(final Object o) {
    final Counter counter = (Counter)this.counts.get(o);
    if (counter == null) {
      this.counts.put(o, new Counter(1));
    } else {
      counter.increment();
    }
  }

  public int count(final Object o) {
    final Counter counter = (Counter)this.counts.get(o);
    if (counter == null) {
      return 0;
    } else {
      return counter.count();
    }

  }
}