/*
 * 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 org.apache.struts2.util;

import java.io.Serial;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;


/**
 * A Stack that is implemented using a List.
 *
 * @author plightbo
 * @version $Revision$
 */
public class CompoundRoot extends CopyOnWriteArrayList<Object> {

    @Serial
    private static final long serialVersionUID = 8563229069192473995L;

    public CompoundRoot() {
    }

    public CompoundRoot(List<?> list) {
        super(list);
    }


    public CompoundRoot cutStack(int index) {
        return new CompoundRoot(subList(index, size()));
    }

    public Object peek() {
        return get(0);
    }

    public Object pop() {
        return remove(0);
    }

    public void push(Object o) {
        add(0, o);
    }
}
