J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1999-2005 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package javax.management; |
| 27 | |
| 28 | import java.util.ArrayList; |
| 29 | import java.util.Collection; |
| 30 | import java.util.List; |
| 31 | |
| 32 | /** |
| 33 | * Represents a list of values for attributes of an MBean. The methods |
| 34 | * used for the insertion of {@link javax.management.Attribute |
| 35 | * Attribute} objects in the <CODE>AttributeList</CODE> overrides the |
| 36 | * corresponding methods in the superclass |
| 37 | * <CODE>ArrayList</CODE>. This is needed in order to insure that the |
| 38 | * objects contained in the <CODE>AttributeList</CODE> are only |
| 39 | * <CODE>Attribute</CODE> objects. This avoids getting an exception |
| 40 | * when retrieving elements from the <CODE>AttributeList</CODE>. |
| 41 | * |
| 42 | * @since 1.5 |
| 43 | */ |
| 44 | /* We cannot extend ArrayList<Attribute> because our legacy |
| 45 | add(Attribute) method would then override add(E) in ArrayList<E>, |
| 46 | and our return value is void whereas ArrayList.add(E)'s is boolean. |
| 47 | Likewise for set(int,Attribute). Grrr. We cannot use covariance |
| 48 | to override the most important methods and have them return |
| 49 | Attribute, either, because that would break subclasses that |
| 50 | override those methods in turn (using the original return type |
| 51 | of Object). Finally, we cannot implement Iterable<Attribute> |
| 52 | so you could write |
| 53 | for (Attribute a : attributeList) |
| 54 | because ArrayList<> implements Iterable<> and the same class cannot |
| 55 | implement two versions of a generic interface. Instead we provide |
| 56 | the asList() method so you can write |
| 57 | for (Attribute a : attributeList.asList()) |
| 58 | */ |
| 59 | public class AttributeList extends ArrayList<Object> { |
| 60 | |
| 61 | private transient boolean typeSafe; |
| 62 | private transient boolean tainted; |
| 63 | |
| 64 | /* Serial version */ |
| 65 | private static final long serialVersionUID = -4077085769279709076L; |
| 66 | |
| 67 | /** |
| 68 | * Constructs an empty <CODE>AttributeList</CODE>. |
| 69 | */ |
| 70 | public AttributeList() { |
| 71 | super(); |
| 72 | } |
| 73 | |
| 74 | /** |
| 75 | * Constructs an empty <CODE>AttributeList</CODE> with |
| 76 | * the initial capacity specified. |
| 77 | * |
| 78 | * @param initialCapacity the initial capacity of the |
| 79 | * <code>AttributeList</code>, as specified by {@link |
| 80 | * ArrayList#ArrayList(int)}. |
| 81 | */ |
| 82 | public AttributeList(int initialCapacity) { |
| 83 | super(initialCapacity); |
| 84 | } |
| 85 | |
| 86 | /** |
| 87 | * Constructs an <CODE>AttributeList</CODE> containing the |
| 88 | * elements of the <CODE>AttributeList</CODE> specified, in the |
| 89 | * order in which they are returned by the |
| 90 | * <CODE>AttributeList</CODE>'s iterator. The |
| 91 | * <CODE>AttributeList</CODE> instance has an initial capacity of |
| 92 | * 110% of the size of the <CODE>AttributeList</CODE> specified. |
| 93 | * |
| 94 | * @param list the <code>AttributeList</code> that defines the initial |
| 95 | * contents of the new <code>AttributeList</code>. |
| 96 | * |
| 97 | * @see ArrayList#ArrayList(java.util.Collection) |
| 98 | */ |
| 99 | public AttributeList(AttributeList list) { |
| 100 | super(list); |
| 101 | } |
| 102 | |
| 103 | /** |
| 104 | * Constructs an {@code AttributeList} containing the elements of the |
| 105 | * {@code List} specified, in the order in which they are returned by |
| 106 | * the {@code List}'s iterator. |
| 107 | * |
| 108 | * @param list the {@code List} that defines the initial contents of |
| 109 | * the new {@code AttributeList}. |
| 110 | * |
| 111 | * @exception IllegalArgumentException if the {@code list} parameter |
| 112 | * is {@code null} or if the {@code list} parameter contains any |
| 113 | * non-Attribute objects. |
| 114 | * |
| 115 | * @see ArrayList#ArrayList(java.util.Collection) |
| 116 | * |
| 117 | * @since 1.6 |
| 118 | */ |
| 119 | public AttributeList(List<Attribute> list) { |
| 120 | // Check for null parameter |
| 121 | // |
| 122 | if (list == null) |
| 123 | throw new IllegalArgumentException("Null parameter"); |
| 124 | |
| 125 | // Check for non-Attribute objects |
| 126 | // |
| 127 | checkTypeSafe(list); |
| 128 | |
| 129 | // Build the List<Attribute> |
| 130 | // |
| 131 | super.addAll(list); |
| 132 | } |
| 133 | |
| 134 | /** |
| 135 | * Return a view of this list as a {@code List<Attribute>}. |
| 136 | * Changes to the returned value are reflected by changes |
| 137 | * to the original {@code AttributeList} and vice versa. |
| 138 | * |
| 139 | * @return a {@code List<Attribute>} whose contents |
| 140 | * reflect the contents of this {@code AttributeList}. |
| 141 | * |
| 142 | * <p>If this method has ever been called on a given |
| 143 | * {@code AttributeList} instance, a subsequent attempt to add |
| 144 | * an object to that instance which is not an {@code Attribute} |
| 145 | * will fail with a {@code IllegalArgumentException}. For compatibility |
| 146 | * reasons, an {@code AttributeList} on which this method has never |
| 147 | * been called does allow objects other than {@code Attribute}s to |
| 148 | * be added.</p> |
| 149 | * |
| 150 | * @throws IllegalArgumentException if this {@code AttributeList} contains |
| 151 | * an element that is not an {@code Attribute}. |
| 152 | * |
| 153 | * @since 1.6 |
| 154 | */ |
| 155 | @SuppressWarnings("unchecked") |
| 156 | public List<Attribute> asList() { |
| 157 | if (!typeSafe) { |
| 158 | if (tainted) |
| 159 | checkTypeSafe(this); |
| 160 | typeSafe = true; |
| 161 | } |
| 162 | return (List<Attribute>) (List) this; |
| 163 | } |
| 164 | |
| 165 | /** |
| 166 | * Adds the {@code Attribute} specified as the last element of the list. |
| 167 | * |
| 168 | * @param object The attribute to be added. |
| 169 | */ |
| 170 | public void add(Attribute object) { |
| 171 | super.add(object); |
| 172 | } |
| 173 | |
| 174 | /** |
| 175 | * Inserts the attribute specified as an element at the position specified. |
| 176 | * Elements with an index greater than or equal to the current position are |
| 177 | * shifted up. If the index is out of range (index < 0 || index > |
| 178 | * size() a RuntimeOperationsException should be raised, wrapping the |
| 179 | * java.lang.IndexOutOfBoundsException thrown. |
| 180 | * |
| 181 | * @param object The <CODE>Attribute</CODE> object to be inserted. |
| 182 | * @param index The position in the list where the new {@code Attribute} |
| 183 | * object is to be inserted. |
| 184 | */ |
| 185 | public void add(int index, Attribute object) { |
| 186 | try { |
| 187 | super.add(index, object); |
| 188 | } |
| 189 | catch (IndexOutOfBoundsException e) { |
| 190 | throw new RuntimeOperationsException(e, |
| 191 | "The specified index is out of range"); |
| 192 | } |
| 193 | } |
| 194 | |
| 195 | /** |
| 196 | * Sets the element at the position specified to be the attribute specified. |
| 197 | * The previous element at that position is discarded. If the index is |
| 198 | * out of range (index < 0 || index > size() a RuntimeOperationsException |
| 199 | * should be raised, wrapping the java.lang.IndexOutOfBoundsException thrown. |
| 200 | * |
| 201 | * @param object The value to which the attribute element should be set. |
| 202 | * @param index The position specified. |
| 203 | */ |
| 204 | public void set(int index, Attribute object) { |
| 205 | try { |
| 206 | super.set(index, object); |
| 207 | } |
| 208 | catch (IndexOutOfBoundsException e) { |
| 209 | throw new RuntimeOperationsException(e, |
| 210 | "The specified index is out of range"); |
| 211 | } |
| 212 | } |
| 213 | |
| 214 | /** |
| 215 | * Appends all the elements in the <CODE>AttributeList</CODE> specified to |
| 216 | * the end of the list, in the order in which they are returned by the |
| 217 | * Iterator of the <CODE>AttributeList</CODE> specified. |
| 218 | * |
| 219 | * @param list Elements to be inserted into the list. |
| 220 | * |
| 221 | * @return true if this list changed as a result of the call. |
| 222 | * |
| 223 | * @see ArrayList#addAll(java.util.Collection) |
| 224 | */ |
| 225 | public boolean addAll(AttributeList list) { |
| 226 | return (super.addAll(list)); |
| 227 | } |
| 228 | |
| 229 | /** |
| 230 | * Inserts all of the elements in the <CODE>AttributeList</CODE> specified |
| 231 | * into this list, starting at the specified position, in the order in which |
| 232 | * they are returned by the Iterator of the {@code AttributeList} specified. |
| 233 | * If the index is out of range (index < 0 || index > size() a |
| 234 | * RuntimeOperationsException should be raised, wrapping the |
| 235 | * java.lang.IndexOutOfBoundsException thrown. |
| 236 | * |
| 237 | * @param list Elements to be inserted into the list. |
| 238 | * @param index Position at which to insert the first element from the |
| 239 | * <CODE>AttributeList</CODE> specified. |
| 240 | * |
| 241 | * @return true if this list changed as a result of the call. |
| 242 | * |
| 243 | * @see ArrayList#addAll(int, java.util.Collection) |
| 244 | */ |
| 245 | public boolean addAll(int index, AttributeList list) { |
| 246 | try { |
| 247 | return super.addAll(index, list); |
| 248 | } |
| 249 | catch (IndexOutOfBoundsException e) { |
| 250 | throw new RuntimeOperationsException(e, |
| 251 | "The specified index is out of range"); |
| 252 | } |
| 253 | } |
| 254 | |
| 255 | /* |
| 256 | * Override all of the methods from ArrayList<Object> that might add |
| 257 | * a non-Attribute to the List, and disallow that if asList has ever |
| 258 | * been called on this instance. |
| 259 | */ |
| 260 | |
| 261 | @Override |
| 262 | public boolean add(Object o) { |
| 263 | if (!tainted) |
| 264 | tainted = isTainted(o); |
| 265 | if (typeSafe) |
| 266 | checkTypeSafe(o); |
| 267 | return super.add(o); |
| 268 | } |
| 269 | |
| 270 | @Override |
| 271 | public void add(int index, Object element) { |
| 272 | if (!tainted) |
| 273 | tainted = isTainted(element); |
| 274 | if (typeSafe) |
| 275 | checkTypeSafe(element); |
| 276 | super.add(index, element); |
| 277 | } |
| 278 | |
| 279 | @Override |
| 280 | public boolean addAll(Collection<?> c) { |
| 281 | if (!tainted) |
| 282 | tainted = isTainted(c); |
| 283 | if (typeSafe) |
| 284 | checkTypeSafe(c); |
| 285 | return super.addAll(c); |
| 286 | } |
| 287 | |
| 288 | @Override |
| 289 | public boolean addAll(int index, Collection<?> c) { |
| 290 | if (!tainted) |
| 291 | tainted = isTainted(c); |
| 292 | if (typeSafe) |
| 293 | checkTypeSafe(c); |
| 294 | return super.addAll(index, c); |
| 295 | } |
| 296 | |
| 297 | @Override |
| 298 | public Object set(int index, Object element) { |
| 299 | if (!tainted) |
| 300 | tainted = isTainted(element); |
| 301 | if (typeSafe) |
| 302 | checkTypeSafe(element); |
| 303 | return super.set(index, element); |
| 304 | } |
| 305 | |
| 306 | /** |
| 307 | * IllegalArgumentException if o is a non-Attribute object. |
| 308 | */ |
| 309 | private static void checkTypeSafe(Object o) { |
| 310 | try { |
| 311 | o = (Attribute) o; |
| 312 | } catch (ClassCastException e) { |
| 313 | throw new IllegalArgumentException(e); |
| 314 | } |
| 315 | } |
| 316 | |
| 317 | /** |
| 318 | * IllegalArgumentException if c contains any non-Attribute objects. |
| 319 | */ |
| 320 | private static void checkTypeSafe(Collection<?> c) { |
| 321 | try { |
| 322 | Attribute a; |
| 323 | for (Object o : c) |
| 324 | a = (Attribute) o; |
| 325 | } catch (ClassCastException e) { |
| 326 | throw new IllegalArgumentException(e); |
| 327 | } |
| 328 | } |
| 329 | |
| 330 | /** |
| 331 | * Returns true if o is a non-Attribute object. |
| 332 | */ |
| 333 | private static boolean isTainted(Object o) { |
| 334 | try { |
| 335 | checkTypeSafe(o); |
| 336 | } catch (IllegalArgumentException e) { |
| 337 | return true; |
| 338 | } |
| 339 | return false; |
| 340 | } |
| 341 | |
| 342 | /** |
| 343 | * Returns true if c contains any non-Attribute objects. |
| 344 | */ |
| 345 | private static boolean isTainted(Collection<?> c) { |
| 346 | try { |
| 347 | checkTypeSafe(c); |
| 348 | } catch (IllegalArgumentException e) { |
| 349 | return true; |
| 350 | } |
| 351 | return false; |
| 352 | } |
| 353 | } |