future.java

来自「Mobile 应用程序使用 Java Micro Edition (Java M」· Java 代码 · 共 34 行

/*
 * @(#)Future.java	1.10 05/11/17
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package com.sun.corba.se.impl.orbutil.closure ;

import com.sun.corba.se.spi.orbutil.closure.Closure ;

public class Future implements Closure {
    private boolean evaluated ;
    private Closure closure ;
    private Object value ;

    public Future( Closure value )
    {
	this.evaluated = false ;
	this.closure = (Closure)value ;
	this.value = null ;
    }
    
    public synchronized Object evaluate() 
    {
	if (!evaluated) {
	    evaluated = true ;
	    value = closure.evaluate() ;
	}

	return value ;
    }
}