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/* |
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* %W% %E% |
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* Copyright 1997-2006 Sun Microsystems, Inc. All Rights Reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* Copyright 2006 Sun Microsystems, Inc. All rights reserved. |
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* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Sun designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Sun in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
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* CA 95054 USA or visit www.sun.com if you need additional information or |
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* have any questions. |
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*/ |
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package java.util; |
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* <tt>Collection</tt> constructor, as per the recommendation in the |
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* <tt>Collection</tt> interface specification.<p> |
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* |
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* The documentation for each non-abstract methods in this class describes its |
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* The documentation for each non-abstract method in this class describes its |
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* implementation in detail. Each of these methods may be overridden if |
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* the collection being implemented admits a more efficient implementation.<p> |
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* |
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/** |
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* {@inheritDoc} |
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* |
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* <p>This implementation allocates the array to be returned, and iterates |
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* over the elements in the collection, storing each object reference in |
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* the next consecutive element of the array, starting with element 0. |
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* <p>This implementation returns an array containing all the elements |
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* returned by this collection's iterator, in the same order, stored in |
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* consecutive elements of the array, starting with index {@code 0}. |
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* The length of the returned array is equal to the number of elements |
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* returned by the iterator, even if the size of this collection changes |
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* during iteration, as might happen if the collection permits |
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* concurrent modification during iteration. The {@code size} method is |
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* called only as an optimization hint; the correct result is returned |
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* even if the iterator returns a different number of elements. |
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* |
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* <p>This method is equivalent to: |
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* |
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* <pre> {@code |
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* List<E> list = new ArrayList<E>(size()); |
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* for (E e : this) |
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* list.add(e); |
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* return list.toArray(); |
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* }</pre> |
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*/ |
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public Object[] toArray() { |
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// Estimate size of array; be prepared to see more or fewer elements |
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Object[] r = new Object[size()]; |
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int i = 0; |
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Iterator<E> it = iterator(); |
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while (i < r.length && it.hasNext()) |
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r[i++] = it.next(); |
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// Trim if overallocated; expand if underallocated |
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if (i < r.length || it.hasNext()) |
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return resizeAndFinishToArray(r, i, it); |
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return r; |
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for (int i = 0; i < r.length; i++) { |
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if (! it.hasNext()) // fewer elements than expected |
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return Arrays.copyOf(r, i); |
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r[i] = it.next(); |
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} |
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return it.hasNext() ? finishToArray(r, it) : r; |
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} |
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|
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/** |
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* {@inheritDoc} |
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* |
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* <p>This implementation checks if the array is large enough to contain the |
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* collection; if not, it allocates a new array of the correct size and |
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* type (using reflection). Then, it iterates over the collection, |
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* storing each object reference in the next consecutive element of the |
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* array, starting with element 0. If the array is larger than the |
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* collection, a <tt>null</tt> is stored in the first location after the |
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* end of the collection. |
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* <p>This implementation returns an array containing all the elements |
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* returned by this collection's iterator in the same order, stored in |
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* consecutive elements of the array, starting with index {@code 0}. |
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* If the number of elements returned by the iterator is too large to |
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* fit into the specified array, then the elements are returned in a |
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* newly allocated array with length equal to the number of elements |
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* returned by the iterator, even if the size of this collection |
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* changes during iteration, as might happen if the collection permits |
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* concurrent modification during iteration. The {@code size} method is |
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* called only as an optimization hint; the correct result is returned |
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* even if the iterator returns a different number of elements. |
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* |
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* <p>This method is equivalent to: |
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* |
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* <pre> {@code |
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* List<E> list = new ArrayList<E>(size()); |
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* for (E e : this) |
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* list.add(e); |
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* return list.toArray(a); |
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* }</pre> |
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* |
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* @throws ArrayStoreException {@inheritDoc} |
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* @throws NullPointerException {@inheritDoc} |
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T[] r = a.length >= size ? a : |
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(T[])java.lang.reflect.Array |
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.newInstance(a.getClass().getComponentType(), size); |
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int i = 0; |
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Iterator<E> it = iterator(); |
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while (i < r.length && it.hasNext()) |
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r[i++] = (T)it.next(); |
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// Trim if overallocated; expand if underallocated |
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if (it.hasNext() || (r != a && i < r.length)) |
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return resizeAndFinishToArray(r, i, it); |
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if (i < r.length) |
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r[i] = null; // null-terminate if provided array is too big |
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return r; |
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|
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for (int i = 0; i < r.length; i++) { |
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if (! it.hasNext()) { // fewer elements than expected |
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if (a != r) |
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return Arrays.copyOf(r, i); |
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r[i] = null; // null-terminate |
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return r; |
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} |
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r[i] = (T)it.next(); |
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} |
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return it.hasNext() ? finishToArray(r, it) : r; |
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} |
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/** |
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* Reallocates the array being used within toArray that has a |
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* different number of elements than expected, and finishes |
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* filling it from the given iterator, if necessary. |
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* |
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* @param r the array |
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* @param i the next array index to fill |
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* @param it the in-progress iterator over the collection |
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* Reallocates the array being used within toArray when the iterator |
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* returned more elements than expected, and finishes filling it from |
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* the iterator. |
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* |
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* @param r the array, replete with previously stored elements |
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* @param it the in-progress iterator over this collection |
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* @return array containing the elements in the given array, plus any |
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* further elements returned by the iterator, trimmed to size |
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*/ |
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private static <T> T[] resizeAndFinishToArray(T[] r, int i, Iterator<?> it) { |
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private static <T> T[] finishToArray(T[] r, Iterator<?> it) { |
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int i = r.length; |
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while (it.hasNext()) { |
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int cap = r.length; |
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if (i < cap) |
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r[i++] = (T)it.next(); |
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else { |
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if (i == cap) { |
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int newCap = ((cap / 2) + 1) * 3; |
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if (newCap <= cap) { // integer overflow |
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if (cap == Integer.MAX_VALUE) |
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throw new OutOfMemoryError |
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("Required array size too large"); |
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newCap = Integer.MAX_VALUE; |
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newCap = Integer.MAX_VALUE; |
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} |
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r = Arrays.copyOf(r, newCap); |
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} |
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r = Arrays.copyOf(r, newCap); |
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} |
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r[i++] = (T)it.next(); |
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} |
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// trim if overallocated |
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return i == r.length ? r : Arrays.copyOf(r, i); |
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return (i == r.length) ? r : Arrays.copyOf(r, i); |
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} |
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// Modification Operations |
