corba/src/share/classes/com/sun/corba/se/impl/orbutil/closure/Future.java

/*
 * Copyright (c) 2000, 2003, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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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 ;
    }
}