content: /*
   * Copyright (C) 2017 The Android Open Source Project
   *
   * Licensed 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.android.server.wm;
  
  import java.util.ArrayList;
  
  /**
   * An {@link ArrayList} with extended functionality to be used as the children data structure in
   * {@link WindowContainer}.
   */
  class WindowList<E> extends ArrayList<E> {
  
      void addFirst(E e) {
          add(0, e);
      }
  
      E peekLast() {
          return size() > 0 ? get(size() - 1) : null;
      }
  
      E peekFirst() {
          return size() > 0 ? get(0) : null;
      }
  }
  