001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   https://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.bcel.util;
020
021import java.util.LinkedList;
022
023import org.apache.bcel.classfile.JavaClass;
024
025/**
026 * Utility class implementing a (typesafe) queue of JavaClass objects.
027 */
028public class ClassQueue {
029
030    /**
031     * @deprecated (since 6.0) will be made private; do not access
032     */
033    @Deprecated
034    protected LinkedList<JavaClass> vec = new LinkedList<>(); // TODO not used externally
035
036    /**
037     * Constructs a new ClassQueue.
038     */
039    public ClassQueue() {
040    }
041
042    /**
043     * Removes and returns the first JavaClass from the queue.
044     *
045     * @return the first JavaClass from the queue.
046     */
047    public JavaClass dequeue() {
048        return vec.removeFirst();
049    }
050
051    /**
052     * Checks if the queue is empty.
053     *
054     * @return true if the queue is empty.
055     */
056    public boolean empty() {
057        return vec.isEmpty();
058    }
059
060    /**
061     * Adds a JavaClass to the end of the queue.
062     *
063     * @param clazz the JavaClass to add.
064     */
065    public void enqueue(final JavaClass clazz) {
066        vec.addLast(clazz);
067    }
068
069    @Override
070    public String toString() {
071        return vec.toString();
072    }
073}