maps.java

来自「用JAVA编写的软件度量方面的源码」· Java 代码 · 共 40 行

/* MetricsAnalyzer
 * Copyright (C) 2002  TIKE (tike.mmm.fi)
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This program 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 General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc., 59
 * Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

package metricsanalyzer.util;

import java.util.Map;

/**
 * Utility functions for dealing with Maps.
 */
public class Maps {
  public static Object putIdentity(Map map, Object keyValue) {
    return putOnce(map, keyValue, keyValue);
  }

  public static Object putOnce(Map map, Object key, Object value) {
    Object result = map.get(key);
    if (null == result) {
      result = value;
      map.put(key, result);
    }
    return result;
  }
}