ConsecutiveMap.java

package org.cdlib.xtf.util;


/**
 * Copyright (c) 2004, Regents of the University of California
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * - Neither the name of the University of California nor the names of its
 *   contributors may be used to endorse or promote products derived from this
 *   software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
import java.util.HashMap;
import java.util.Vector;

/**
 * Implements a simple mapping, from object keys to integers. Each new key
 * is assigned a consecutive number, starting at zero.
 *
 * @author Martin Haye
 */
public class ConsecutiveMap 
{
  /** Mapping used to keep the unique set of keys */
  private HashMap map = new HashMap(100);

  /** Vector of all unique keys, in order of addition */
  private Vector inOrder = new Vector(100);

  /**
   * If the key is already present in the map, return its assigned number.
   * Otherwise, add it and assign it a new number.
   *
   * @param key   The key to look up
   * @return      A number associated with that key
   */
  public int put(Object key) 
  {
    Integer num = (Integer)map.get(key);
    if (num == null) {
      num = Integer.valueOf(inOrder.size());
      inOrder.add(key);
      map.put(key, num);
    }

    return num.intValue();
  } // put()

  /**
   * Retrieve the namecode for the given key. If not found, returns -1.
   */
  public int get(Object key) {
    Object num = map.get(key);
    if (num == null)
      return -1;
    return ((Integer)num).intValue();
  } // get()

  /**
   * Check if the given key is present in the map yet.
   */
  public boolean has(Object key) {
    return map.get(key) != null;
  } // has()

  /**
   * Retrieve an array of all the keys, ordered by consecutive number.
   */
  public Object[] getArray() {
    return inOrder.toArray();
  } // getArray()
} // class ConsecutiveMap