javassist/src/main/javassist/bytecode/analysis/IntQueue.java

/*
 * 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 javassist.bytecode.analysis;

import java.util.NoSuchElementException;

class IntQueue {
    private static class Entry {
        private IntQueue.Entry next;
        private int value;
        private Entry(int value) {
            this.value = value;
        }
    }
    private IntQueue.Entry head;

    private IntQueue.Entry tail;

    void add(int value) {
        IntQueue.Entry entry = new Entry(value);
        if (tail != null)
            tail.next = entry;
        tail = entry;

        if (head == null)
            head = entry;
    }

    boolean isEmpty() {
        return head == null;
    }

    int take() {
        if (head == null)
            throw new NoSuchElementException();

        int value = head.value;
        head = head.next;
        if (head == null)
            tail = null;

        return value;
    }
}