| 26 |
|
* <tt>Collection</tt> constructor, as per the recommendation in the |
| 27 |
|
* <tt>Collection</tt> interface specification.<p> |
| 28 |
|
* |
| 29 |
< |
* The documentation for each non-abstract methods in this class describes its |
| 29 |
> |
* The documentation for each non-abstract method in this class describes its |
| 30 |
|
* implementation in detail. Each of these methods may be overridden if |
| 31 |
|
* the collection being implemented admits a more efficient implementation.<p> |
| 32 |
|
* |
| 95 |
|
/** |
| 96 |
|
* {@inheritDoc} |
| 97 |
|
* |
| 98 |
< |
* <p>This implementation allocates the array to be returned, and iterates |
| 99 |
< |
* over the elements in the collection, storing each object reference in |
| 100 |
< |
* the next consecutive element of the array, starting with element 0. |
| 98 |
> |
* <p>This implementation returns an array containing all the elements |
| 99 |
> |
* returned by this collection's iterator, in the same order, stored in |
| 100 |
> |
* consecutive elements of the array, starting with index {@code 0}. |
| 101 |
> |
* The length of the returned array is equal to the number of elements |
| 102 |
> |
* returned by the iterator, even if the size of this collection changes |
| 103 |
> |
* during iteration, as might happen if the collection permits |
| 104 |
> |
* concurrent modification during iteration. The {@code size} method is |
| 105 |
> |
* called only as an optimization hint; the correct result is returned |
| 106 |
> |
* even if the iterator returns a different number of elements. |
| 107 |
> |
* |
| 108 |
> |
* <p>This method is equivalent to: |
| 109 |
> |
* |
| 110 |
> |
* <pre> {@code |
| 111 |
> |
* List<E> list = new ArrayList<E>(size()); |
| 112 |
> |
* for (E e : this) |
| 113 |
> |
* list.add(e); |
| 114 |
> |
* return list.toArray(); |
| 115 |
> |
* }</pre> |
| 116 |
|
*/ |
| 117 |
|
public Object[] toArray() { |
| 118 |
|
// Estimate size of array; be prepared to see more or fewer elements |
| 119 |
|
Object[] r = new Object[size()]; |
| 105 |
– |
int i = 0; |
| 120 |
|
Iterator<E> it = iterator(); |
| 121 |
< |
while (i < r.length && it.hasNext()) |
| 122 |
< |
r[i++] = it.next(); |
| 123 |
< |
// Trim if overallocated; expand if underallocated |
| 124 |
< |
if (i < r.length || it.hasNext()) |
| 125 |
< |
return resizeAndFinishToArray(r, i, it); |
| 126 |
< |
return r; |
| 121 |
> |
for (int i = 0; i < r.length; i++) { |
| 122 |
> |
if (! it.hasNext()) // fewer elements than expected |
| 123 |
> |
return Arrays.copyOf(r, i); |
| 124 |
> |
r[i] = it.next(); |
| 125 |
> |
} |
| 126 |
> |
return it.hasNext() ? finishToArray(r, it) : r; |
| 127 |
|
} |
| 128 |
|
|
| 129 |
|
/** |
| 130 |
|
* {@inheritDoc} |
| 131 |
|
* |
| 132 |
< |
* <p>This implementation checks if the array is large enough to contain the |
| 133 |
< |
* collection; if not, it allocates a new array of the correct size and |
| 134 |
< |
* type (using reflection). Then, it iterates over the collection, |
| 135 |
< |
* storing each object reference in the next consecutive element of the |
| 136 |
< |
* array, starting with element 0. If the array is larger than the |
| 137 |
< |
* collection, a <tt>null</tt> is stored in the first location after the |
| 138 |
< |
* end of the collection. |
| 132 |
> |
* <p>This implementation returns an array containing all the elements |
| 133 |
> |
* returned by this collection's iterator in the same order, stored in |
| 134 |
> |
* consecutive elements of the array, starting with index {@code 0}. |
| 135 |
> |
* If the number of elements returned by the iterator is too large to |
| 136 |
> |
* fit into the specified array, then the elements are returned in a |
| 137 |
> |
* newly allocated array with length equal to the number of elements |
| 138 |
> |
* returned by the iterator, even if the size of this collection |
| 139 |
> |
* changes during iteration, as might happen if the collection permits |
| 140 |
> |
* concurrent modification during iteration. The {@code size} method is |
| 141 |
> |
* called only as an optimization hint; the correct result is returned |
| 142 |
> |
* even if the iterator returns a different number of elements. |
| 143 |
> |
* |
| 144 |
> |
* <p>This method is equivalent to: |
| 145 |
> |
* |
| 146 |
> |
* <pre> {@code |
| 147 |
> |
* List<E> list = new ArrayList<E>(size()); |
| 148 |
> |
* for (E e : this) |
| 149 |
> |
* list.add(e); |
| 150 |
> |
* return list.toArray(a); |
| 151 |
> |
* }</pre> |
| 152 |
|
* |
| 153 |
|
* @throws ArrayStoreException {@inheritDoc} |
| 154 |
|
* @throws NullPointerException {@inheritDoc} |
| 159 |
|
T[] r = a.length >= size ? a : |
| 160 |
|
(T[])java.lang.reflect.Array |
| 161 |
|
.newInstance(a.getClass().getComponentType(), size); |
| 135 |
– |
int i = 0; |
| 162 |
|
Iterator<E> it = iterator(); |
| 163 |
< |
while (i < r.length && it.hasNext()) |
| 164 |
< |
r[i++] = (T)it.next(); |
| 165 |
< |
// Trim if overallocated; expand if underallocated |
| 166 |
< |
if (it.hasNext() || (r != a && i < r.length)) |
| 167 |
< |
return resizeAndFinishToArray(r, i, it); |
| 168 |
< |
if (i < r.length) |
| 169 |
< |
r[i] = null; // null-terminate if provided array is too big |
| 170 |
< |
return r; |
| 163 |
> |
|
| 164 |
> |
for (int i = 0; i < r.length; i++) { |
| 165 |
> |
if (! it.hasNext()) { // fewer elements than expected |
| 166 |
> |
if (a != r) |
| 167 |
> |
return Arrays.copyOf(r, i); |
| 168 |
> |
r[i] = null; // null-terminate |
| 169 |
> |
return r; |
| 170 |
> |
} |
| 171 |
> |
r[i] = (T)it.next(); |
| 172 |
> |
} |
| 173 |
> |
return it.hasNext() ? finishToArray(r, it) : r; |
| 174 |
|
} |
| 175 |
|
|
| 176 |
|
/** |
| 177 |
< |
* Reallocates the array being used within toArray that has a |
| 178 |
< |
* different number of elements than expected, and finishes |
| 179 |
< |
* filling it from the given iterator, if necessary. |
| 180 |
< |
* |
| 181 |
< |
* @param r the array |
| 182 |
< |
* @param i the next array index to fill |
| 154 |
< |
* @param it the in-progress iterator over the collection |
| 177 |
> |
* Reallocates the array being used within toArray when the iterator |
| 178 |
> |
* returned more elements than expected, and finishes filling it from |
| 179 |
> |
* the iterator. |
| 180 |
> |
* |
| 181 |
> |
* @param r the array, replete with previously stored elements |
| 182 |
> |
* @param it the in-progress iterator over this collection |
| 183 |
|
* @return array containing the elements in the given array, plus any |
| 184 |
|
* further elements returned by the iterator, trimmed to size |
| 185 |
|
*/ |
| 186 |
< |
private static <T> T[] resizeAndFinishToArray(T[] r, int i, Iterator<?> it) { |
| 186 |
> |
private static <T> T[] finishToArray(T[] r, Iterator<?> it) { |
| 187 |
> |
int i = r.length; |
| 188 |
|
while (it.hasNext()) { |
| 189 |
|
int cap = r.length; |
| 190 |
< |
if (i < cap) |
| 162 |
< |
r[i++] = (T)it.next(); |
| 163 |
< |
else { |
| 190 |
> |
if (i == cap) { |
| 191 |
|
int newCap = ((cap / 2) + 1) * 3; |
| 192 |
|
if (newCap <= cap) { // integer overflow |
| 193 |
|
if (cap == Integer.MAX_VALUE) |
| 194 |
|
throw new OutOfMemoryError |
| 195 |
|
("Required array size too large"); |
| 196 |
< |
newCap = Integer.MAX_VALUE; |
| 196 |
> |
newCap = Integer.MAX_VALUE; |
| 197 |
|
} |
| 198 |
< |
r = Arrays.copyOf(r, newCap); |
| 199 |
< |
} |
| 198 |
> |
r = Arrays.copyOf(r, newCap); |
| 199 |
> |
} |
| 200 |
> |
r[i++] = (T)it.next(); |
| 201 |
|
} |
| 202 |
|
// trim if overallocated |
| 203 |
< |
return i == r.length ? r : Arrays.copyOf(r, i); |
| 203 |
> |
return (i == r.length) ? r : Arrays.copyOf(r, i); |
| 204 |
|
} |
| 205 |
|
|
| 206 |
|
// Modification Operations |
