keygenerator.java

来自「《JAVA与模式》附书中源代码」· Java 代码 · 共 48 行

package com.javapatterns.keygen.ver5;

import java.util.HashMap;

public class KeyGenerator
{
    /**
     * @label creates 
     */
	private static HashMap kengens
        = new HashMap(10);

    private static final int POOL_SIZE = 20;
    private KeyInfo keyinfo;

    /** @link dependency */
    /*# KeyInfo lnkKeyInfo; */

    private KeyGenerator()
    {
    }

    private KeyGenerator(String keyName)
    {
		keyinfo = new KeyInfo(POOL_SIZE, keyName);
    }

    public static synchronized KeyGenerator
        getInstance(String keyName)
    {
        KeyGenerator keygen;
		if (kengens.containsKey(keyName))
        {
			keygen = (KeyGenerator)
                kengens.get(keyName);
        }
        else
        {
            keygen = new KeyGenerator(keyName);
        }
    	return keygen;
    }

    public int getNextKey()
    {
        return keyinfo.getNextKey();
    }
}