namegenerator.java

来自「java实现浏览器等本地桌面的功能」· Java 代码 · 共 67 行

/*
 * $Id: NameGenerator.java,v 1.5 2005/10/15 20:06:50 rbair Exp $
 *
 * Copyright 2005 Sun Microsystems, Inc., 4150 Network Circle,
 * Santa Clara, California 95054, U.S.A. All rights reserved.
 *
 * 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
 */

package org.jdesktop.dataset;
import java.util.Map;
import java.util.WeakHashMap;

/**
 * Generates unique names. Give it a prefix, it adds a numeric postfix. 
 * Simple use: 
 * <pre>
 * NameGenerator ng = new NameGenerator("DATA_TABLE");
 * String newName = ng.generateName(ng);
 * String newName2 = ng.generateName(ng);
 * String newName3 = ng.generateName(ng);
 * </pre>
 *
 * @author rbair
 */
class NameGenerator {
    /** The prefix for all names generated by this instance. */
    private String prefix;
    
    private int postfix = 1;
    
    /** 
     * Creates a new instance of NameGenerator.
     *
     * @param prefix The prefix for all new names generated by this instance.
     */
    public NameGenerator(String prefix) {
        this.prefix = prefix;
    }
    
    /**
     * Generates a new unique name based on the prefix. The object reference is used
     * to associate with the generated name. The object reference is kept in a
     * weak reference, so that when this object retains the last reference to
     * obj, the generated name can be removed automatically; generated names are thus 
     * unique by NG instance + object instance.
     *
     * @param obj The object to use as a tracker for unique names.
     * @return a unique name beginning with the prefix given in the constructor.
     */
    public String generateName(Object obj) {
        return prefix + postfix++;
    }    
}