src/share/classes/java/util/ArrayList.java

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rev 6970 : [mq]: collections


   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.util;
  27 




  28 /**
  29  * Resizable-array implementation of the <tt>List</tt> interface.  Implements
  30  * all optional list operations, and permits all elements, including
  31  * <tt>null</tt>.  In addition to implementing the <tt>List</tt> interface,
  32  * this class provides methods to manipulate the size of the array that is
  33  * used internally to store the list.  (This class is roughly equivalent to
  34  * <tt>Vector</tt>, except that it is unsynchronized.)
  35  *
  36  * <p>The <tt>size</tt>, <tt>isEmpty</tt>, <tt>get</tt>, <tt>set</tt>,
  37  * <tt>iterator</tt>, and <tt>listIterator</tt> operations run in constant
  38  * time.  The <tt>add</tt> operation runs in <i>amortized constant time</i>,
  39  * that is, adding n elements requires O(n) time.  All of the other operations
  40  * run in linear time (roughly speaking).  The constant factor is low compared
  41  * to that for the <tt>LinkedList</tt> implementation.
  42  *
  43  * <p>Each <tt>ArrayList</tt> instance has a <i>capacity</i>.  The capacity is
  44  * the size of the array used to store the elements in the list.  It is always
  45  * at least as large as the list size.  As elements are added to an ArrayList,
  46  * its capacity grows automatically.  The details of the growth policy are not
  47  * specified beyond the fact that adding an element has constant amortized


1150         }
1151 
1152         private void rangeCheck(int index) {
1153             if (index < 0 || index >= this.size)
1154                 throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
1155         }
1156 
1157         private void rangeCheckForAdd(int index) {
1158             if (index < 0 || index > this.size)
1159                 throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
1160         }
1161 
1162         private String outOfBoundsMsg(int index) {
1163             return "Index: "+index+", Size: "+this.size;
1164         }
1165 
1166         private void checkForComodification() {
1167             if (ArrayList.this.modCount != this.modCount)
1168                 throw new ConcurrentModificationException();
1169         }




















































































1170     }
1171 }


   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.util;
  27 
  28 import java.util.function.Consumer;
  29 import java.util.function.Predicate;
  30 import java.util.function.UnaryOperator;
  31 
  32 /**
  33  * Resizable-array implementation of the <tt>List</tt> interface.  Implements
  34  * all optional list operations, and permits all elements, including
  35  * <tt>null</tt>.  In addition to implementing the <tt>List</tt> interface,
  36  * this class provides methods to manipulate the size of the array that is
  37  * used internally to store the list.  (This class is roughly equivalent to
  38  * <tt>Vector</tt>, except that it is unsynchronized.)
  39  *
  40  * <p>The <tt>size</tt>, <tt>isEmpty</tt>, <tt>get</tt>, <tt>set</tt>,
  41  * <tt>iterator</tt>, and <tt>listIterator</tt> operations run in constant
  42  * time.  The <tt>add</tt> operation runs in <i>amortized constant time</i>,
  43  * that is, adding n elements requires O(n) time.  All of the other operations
  44  * run in linear time (roughly speaking).  The constant factor is low compared
  45  * to that for the <tt>LinkedList</tt> implementation.
  46  *
  47  * <p>Each <tt>ArrayList</tt> instance has a <i>capacity</i>.  The capacity is
  48  * the size of the array used to store the elements in the list.  It is always
  49  * at least as large as the list size.  As elements are added to an ArrayList,
  50  * its capacity grows automatically.  The details of the growth policy are not
  51  * specified beyond the fact that adding an element has constant amortized


1154         }
1155 
1156         private void rangeCheck(int index) {
1157             if (index < 0 || index >= this.size)
1158                 throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
1159         }
1160 
1161         private void rangeCheckForAdd(int index) {
1162             if (index < 0 || index > this.size)
1163                 throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
1164         }
1165 
1166         private String outOfBoundsMsg(int index) {
1167             return "Index: "+index+", Size: "+this.size;
1168         }
1169 
1170         private void checkForComodification() {
1171             if (ArrayList.this.modCount != this.modCount)
1172                 throw new ConcurrentModificationException();
1173         }
1174     }
1175 
1176     @Override
1177     public void forEach(Consumer<? super E> action) {
1178         Objects.requireNonNull(action);
1179         final int expectedModCount = modCount;
1180         @SuppressWarnings("unchecked")
1181         final E[] elementData = (E[]) this.elementData;
1182         final int size = this.size;
1183         for (int i=0; modCount == expectedModCount && i < size; i++) {
1184             action.accept(elementData[i]);
1185         }
1186         if (modCount != expectedModCount) {
1187             throw new ConcurrentModificationException();
1188         }
1189     }
1190 
1191     @Override
1192     public boolean removeIf(Predicate<? super E> filter) {
1193         Objects.requireNonNull(filter);
1194         // figure out which elements are to be removed
1195         // any exception thrown from the filter predicate at this stage
1196         // will leave the collection unmodified
1197         int removeCount = 0;
1198         final BitSet removeSet = new BitSet(size);
1199         final int expectedModCount = modCount;
1200         final int size = this.size;
1201         for (int i=0; modCount == expectedModCount && i < size; i++) {
1202             @SuppressWarnings("unchecked")
1203             final E element = (E) elementData[i];
1204             if (filter.test(element)) {
1205                 removeSet.set(i);
1206                 removeCount++;
1207             }
1208         }
1209         if (modCount != expectedModCount) {
1210             throw new ConcurrentModificationException();
1211         }
1212 
1213         // shift surviving elements left over the spaces left by removed elements
1214         final boolean anyToRemove = removeCount > 0;
1215         if (anyToRemove) {
1216             final int newSize = size - removeCount;
1217             for (int i=0, j=0; (i < size) && (j < newSize); i++, j++) {
1218                 i = removeSet.nextClearBit(i);
1219                 elementData[j] = elementData[i];
1220             }
1221             for (int k=newSize; k < size; k++) {
1222                 elementData[k] = null;  // Let gc do its work
1223             }
1224             this.size = newSize;
1225             if (modCount != expectedModCount) {
1226                 throw new ConcurrentModificationException();
1227             }
1228             modCount++;
1229         }
1230 
1231         return anyToRemove;
1232     }
1233 
1234     @Override
1235     @SuppressWarnings("unchecked")
1236     public void replaceAll(UnaryOperator<E> operator) {
1237         Objects.requireNonNull(operator);
1238         final int expectedModCount = modCount;
1239         final int size = this.size;
1240         for (int i=0; modCount == expectedModCount && i < size; i++) {
1241             elementData[i] = operator.apply((E) elementData[i]);
1242         }
1243         if (modCount != expectedModCount) {
1244             throw new ConcurrentModificationException();
1245         }
1246         modCount++;
1247     }
1248 
1249     @Override
1250     @SuppressWarnings("unchecked")
1251     public void sort(Comparator<? super E> c) {
1252         final int expectedModCount = modCount;
1253         Arrays.sort((E[]) elementData, 0, size, c);
1254         if (modCount != expectedModCount) {
1255             throw new ConcurrentModificationException();
1256         }
1257         modCount++;
1258     }
1259 }