001/* 002 * (C) Copyright 2010 Nuxeo SA (http://nuxeo.com/) and others. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 * 016 * Contributors: 017 * Anahide Tchertchian 018 */ 019package org.nuxeo.ecm.platform.smart.query; 020 021import java.util.LinkedList; 022 023/** 024 * Linked list with a capacity to handle undo/redo actions. 025 * <p> 026 * The method {@link #addLast(Object)} will remove the first object of the list when at full capacity. 027 * 028 * @since 5.4 029 * @author Anahide Tchertchian 030 */ 031public class HistoryList<E> extends LinkedList<E> { 032 033 private static final long serialVersionUID = 1L; 034 035 protected int capacity; 036 037 public HistoryList(int capacity) { 038 super(); 039 this.capacity = capacity; 040 } 041 042 @Override 043 public void addLast(E o) { 044 if (size() >= capacity) { 045 removeFirst(); 046 } 047 super.addLast(o); 048 } 049 050}