001/* 002 * This library is part of OpenCms - 003 * the Open Source Content Management System 004 * 005 * Copyright (c) Alkacon Software GmbH & Co. KG (http://www.alkacon.com) 006 * 007 * This library is free software; you can redistribute it and/or 008 * modify it under the terms of the GNU Lesser General Public 009 * License as published by the Free Software Foundation; either 010 * version 2.1 of the License, or (at your option) any later version. 011 * 012 * This library is distributed in the hope that it will be useful, 013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 015 * Lesser General Public License for more details. 016 * 017 * For further information about Alkacon Software GmbH & Co. KG, please see the 018 * company website: http://www.alkacon.com 019 * 020 * For further information about OpenCms, please see the 021 * project website: http://www.opencms.org 022 * 023 * You should have received a copy of the GNU Lesser General Public 024 * License along with this library; if not, write to the Free Software 025 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 026 */ 027 028package org.opencms.workplace.tools.searchindex; 029 030import java.util.Collection; 031import java.util.Iterator; 032import java.util.LinkedList; 033 034/** 035 * A list intended for subclassing that triggers "listlet" operations that may 036 * access a on a "peer" object 037 * that is provided by a template method to implement in subclasses. <p> 038 * 039 * This is intended to react on modifications on <code>{@link java.util.List}</code> instances 040 * performed by <code>{@link org.opencms.workplace.CmsWidgetDialogParameter}</code> instances 041 * linked to them. Using normal list implementations makes it impossible to intervene in those 042 * list modification by the widget technology.<p> 043 * 044 * "Listlet" operations are operations that are triggered upon modification of this 045 * list. They are called "on<methodName(>[e]d(<peerObject>, <argList>)" 046 * where <methodName> is the name of the original list operation that took place, 047 * "[e]d" stands for the past (operation took place), <peerObject> is the 048 * given class to perform reactions on (see constructors) and 049 * <argList> are the arguments of the original list method in that order. <p> 050 * 051 * Currently only the operations used by <code>{@link org.opencms.workplace.CmsWidgetDialog}</code> 052 * (see implementation of <code>{@link org.opencms.workplace.CmsWidgetDialog#actionToggleElement()}</code>) 053 * are supported and sufficient for this purpose. More general usability enforces extending 054 * the pattern shown here. <p> 055 * 056 * @since 6.0.0 057 */ 058public abstract class CmsHookList extends LinkedList<String> { 059 060 /** Id for safe serialization. */ 061 private static final long serialVersionUID = 3606129489707495072L; 062 063 /** The object operations are made upon. This design cries for 1.5 generics. **/ 064 private Object m_peer; 065 066 /** 067 * Creates an empty list. <p> 068 * 069 * Subclasses should increase "safety by design" by narrowing the type of peer.<p> 070 * 071 * @param peer the object reactions on operations shall be made on in the "listlet" methods of subclasses 072 * 073 */ 074 public CmsHookList(Object peer) { 075 076 super(); 077 m_peer = peer; 078 } 079 080 /** 081 * Creates a list filled with all elements of the given argument. <p> 082 * 083 * Subclasses should increase "safety by design" by narrowing the type of peer.<p> 084 * 085 * @param peer the object reactions on operations shall be made on in the "listlet" methods of subclasses 086 * 087 * @param c a collection with all values for this list 088 */ 089 public CmsHookList(Object peer, Collection<String> c) { 090 091 super(c); 092 m_peer = peer; 093 } 094 095 /** 096 * 097 * @see java.util.List#add(int, java.lang.Object) 098 */ 099 @Override 100 public void add(int index, String element) { 101 102 super.add(index, element); 103 onAdded(m_peer, index, element); 104 105 } 106 107 /** 108 * 109 * @see java.util.Collection#add(java.lang.Object) 110 */ 111 @Override 112 public boolean add(String o) { 113 114 if (super.add(o)) { 115 this.onAdded(m_peer, o); 116 return true; 117 } 118 return false; 119 } 120 121 /** 122 * 123 * @see java.util.Collection#clear() 124 */ 125 @Override 126 public void clear() { 127 128 onClear(m_peer); 129 super.clear(); 130 onCleared(m_peer); 131 } 132 133 /** 134 * 135 * @see java.util.List#get(int) 136 */ 137 @Override 138 public String get(int index) { 139 140 String ret = super.get(index); 141 onGetCall(m_peer, index); 142 return ret; 143 } 144 145 /** 146 * 147 * @see java.util.Collection#iterator() 148 */ 149 @Override 150 public Iterator<String> iterator() { 151 152 Iterator<String> it = super.iterator(); 153 onIteratorCall(m_peer); 154 return it; 155 } 156 157 /** 158 * 159 * @see java.util.List#remove(int) 160 */ 161 @Override 162 public String remove(int index) { 163 164 String ret = null; 165 // get an IndexOutOfBoundsException just like list interfaces contract 166 ret = super.remove(index); 167 return ret; 168 } 169 170 /** 171 * React on the performed operation <code>{@link java.util.List#add(int, java.lang.Object)}</code> 172 * by informing argument peer. <p> 173 * 174 * @param peer the object reactions on operations shall be made on in this "listlet" method 175 * @param index the index the element was added at 176 * @param element the element that was added 177 */ 178 protected abstract void onAdded(Object peer, int index, Object element); 179 180 /** 181 * React on the performed operation <code>{@link java.util.List#add(java.lang.Object)}</code> 182 * by informing argument peer. <p> 183 * 184 * @param peer the object reactions on operations shall be made on in this "listlet" method 185 * @param o the element that was successfully added 186 */ 187 protected abstract void onAdded(Object peer, Object o); 188 189 /** 190 * React on the operation to come <code>{@link java.util.List#clear()}</code> 191 * by informing argument peer. <p> 192 * 193 * This is called before the actual clear operation takes place.<p> 194 * 195 * @param peer the object reactions on operations shall be made on in this "listlet" method 196 */ 197 protected abstract void onClear(Object peer); 198 199 /** 200 * React on the performed operation <code>{@link java.util.List#clear()}</code> 201 * by informing argument peer. <p> 202 * 203 * This is called after the actual clear operation has taken place.<p> 204 * 205 * @param peer the object reactions on operations shall be made on in this "listlet" method 206 */ 207 protected abstract void onCleared(Object peer); 208 209 /** 210 * React on the performed operation <code>{@link java.util.List#get(int)}</code> 211 * by informing argument peer. <p> 212 * 213 * Note that the call reult is only obtained in this instance but not given to the 214 * requesting client when this handler is invoked.<p> 215 * 216 * @param peer the object reactions on operations shall be made on in this "listlet" method 217 * @param index the index of the Object to get 218 */ 219 protected abstract void onGetCall(Object peer, int index); 220 221 /** 222 * React on the performed operation <code>{@link java.util.List#iterator()}</code> 223 * by informing argument peer. <p> 224 * 225 * Note that the iterator is only obtained but not given to the requesting 226 * client when this handler is invoked.<p> 227 * 228 * @param peer the object reactions on operations shall be made on in this "listlet" method 229 */ 230 protected abstract void onIteratorCall(Object peer); 231 232 /** 233 * React on the performed operation <code>{@link java.util.List#remove(int)}</code> 234 * by informing argument peer. <p> 235 * 236 * This is only invoked if the list operation was successful.<p> 237 * 238 * @param peer the object reactions on operations shall be made on in this "listlet" method 239 * @param index the index where the value has been removed 240 */ 241 protected abstract void onRemoved(Object peer, int index); 242 243}