com.feilong.lib.javassist.runtime.Cflow Maven / Gradle / Ivy

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/*
 * Javassist, a Java-bytecode translator toolkit.
 * Copyright (C) 1999- Shigeru Chiba. All Rights Reserved.
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License.  Alternatively, the contents of this file may be used under
 * the terms of the GNU Lesser General Public License Version 2.1 or later,
 * or the Apache License Version 2.0.
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 */

package com.feilong.lib.javassist.runtime;

/**
 * A support class for implementing $cflow.
 * This support class is required at runtime
 * only if $cflow is used.
 *
 * @see com.feilong.lib.javassist.CtBehavior#useCflow(String)
 */
public class Cflow extends ThreadLocal{

    protected static class Depth{

        private int depth;

        Depth(){
            depth = 0;
        }

        int value(){
            return depth;
        }

        void inc(){
            ++depth;
        }

        void dec(){
            --depth;
        }
    }

    @Override
    protected synchronized Depth initialValue(){
        return new Depth();
    }

    /**
     * Increments the counter.
     */
    public void enter(){
        get().inc();
    }

    /**
     * Decrements the counter.
     */
    public void exit(){
        get().dec();
    }

    /**
     * Returns the value of the counter.
     */
    public int value(){
        return get().value();
    }
}