com.google.code.or.common.glossary.Pair.java Source code

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Here is the source code for com.google.code.or.common.glossary.Pair.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.google.code.or.common.glossary;

import org.apache.commons.lang.builder.ToStringBuilder;
import org.apache.commons.lang.builder.ToStringStyle;

/**
 * 
 * @author Jingqi Xu
 */
public final class Pair<T> {
    //
    private T before;
    private T after;

    /**
     * 
     */
    public Pair() {
    }

    public Pair(T before, T after) {
        this.before = before;
        this.after = after;
    }

    /**
     * 
     */
    public String toString() {
        return new ToStringBuilder(this, ToStringStyle.SHORT_PREFIX_STYLE).append("before", before)
                .append("after", after).toString();
    }

    /**
     * 
     */
    public T getBefore() {
        return before;
    }

    public void setBefore(T before) {
        this.before = before;
    }

    public T getAfter() {
        return after;
    }

    public void setAfter(T after) {
        this.after = after;
    }

    /**
     * 
     */
    public void swap() {
        final T t = this.before;
        this.before = this.after;
        this.after = t;
    }

    /**
     * 
     */
    public static void swap(Pair<?> p) {
        doSwap(p); // Nothing but capture the <?>
    }

    private static <T> void doSwap(Pair<T> p) {
        synchronized (p) {
            final T t = p.before;
            p.before = p.after;
            p.after = t;
        }
    }
}