1 |
dl |
1.1 |
/* |
2 |
dl |
1.47 |
* Written by Josh Bloch of Google Inc. and released to the public domain, |
3 |
|
|
* as explained at http://creativecommons.org/publicdomain/zero/1.0/. |
4 |
dl |
1.1 |
*/ |
5 |
|
|
|
6 |
|
|
package java.util; |
7 |
jsr166 |
1.61 |
|
8 |
dl |
1.47 |
import java.io.Serializable; |
9 |
|
|
import java.util.function.Consumer; |
10 |
jsr166 |
1.75 |
import java.util.function.Predicate; |
11 |
|
|
import java.util.function.UnaryOperator; |
12 |
dl |
1.1 |
|
13 |
|
|
/** |
14 |
|
|
* Resizable-array implementation of the {@link Deque} interface. Array |
15 |
|
|
* deques have no capacity restrictions; they grow as necessary to support |
16 |
|
|
* usage. They are not thread-safe; in the absence of external |
17 |
|
|
* synchronization, they do not support concurrent access by multiple threads. |
18 |
|
|
* Null elements are prohibited. This class is likely to be faster than |
19 |
dl |
1.2 |
* {@link Stack} when used as a stack, and faster than {@link LinkedList} |
20 |
dl |
1.1 |
* when used as a queue. |
21 |
|
|
* |
22 |
jsr166 |
1.43 |
* <p>Most {@code ArrayDeque} operations run in amortized constant time. |
23 |
jsr166 |
1.51 |
* Exceptions include |
24 |
|
|
* {@link #remove(Object) remove}, |
25 |
|
|
* {@link #removeFirstOccurrence removeFirstOccurrence}, |
26 |
|
|
* {@link #removeLastOccurrence removeLastOccurrence}, |
27 |
|
|
* {@link #contains contains}, |
28 |
|
|
* {@link #iterator iterator.remove()}, |
29 |
|
|
* and the bulk operations, all of which run in linear time. |
30 |
dl |
1.41 |
* |
31 |
jsr166 |
1.51 |
* <p>The iterators returned by this class's {@link #iterator() iterator} |
32 |
|
|
* method are <em>fail-fast</em>: If the deque is modified at any time after |
33 |
|
|
* the iterator is created, in any way except through the iterator's own |
34 |
|
|
* {@code remove} method, the iterator will generally throw a {@link |
35 |
jsr166 |
1.7 |
* ConcurrentModificationException}. Thus, in the face of concurrent |
36 |
|
|
* modification, the iterator fails quickly and cleanly, rather than risking |
37 |
|
|
* arbitrary, non-deterministic behavior at an undetermined time in the |
38 |
|
|
* future. |
39 |
dl |
1.1 |
* |
40 |
|
|
* <p>Note that the fail-fast behavior of an iterator cannot be guaranteed |
41 |
|
|
* as it is, generally speaking, impossible to make any hard guarantees in the |
42 |
|
|
* presence of unsynchronized concurrent modification. Fail-fast iterators |
43 |
jsr166 |
1.43 |
* throw {@code ConcurrentModificationException} on a best-effort basis. |
44 |
dl |
1.1 |
* Therefore, it would be wrong to write a program that depended on this |
45 |
|
|
* exception for its correctness: <i>the fail-fast behavior of iterators |
46 |
|
|
* should be used only to detect bugs.</i> |
47 |
|
|
* |
48 |
|
|
* <p>This class and its iterator implement all of the |
49 |
jsr166 |
1.9 |
* <em>optional</em> methods of the {@link Collection} and {@link |
50 |
|
|
* Iterator} interfaces. |
51 |
|
|
* |
52 |
|
|
* <p>This class is a member of the |
53 |
jsr166 |
1.29 |
* <a href="{@docRoot}/../technotes/guides/collections/index.html"> |
54 |
jsr166 |
1.9 |
* Java Collections Framework</a>. |
55 |
dl |
1.1 |
* |
56 |
|
|
* @author Josh Bloch and Doug Lea |
57 |
jsr166 |
1.74 |
* @param <E> the type of elements held in this deque |
58 |
dl |
1.1 |
* @since 1.6 |
59 |
|
|
*/ |
60 |
|
|
public class ArrayDeque<E> extends AbstractCollection<E> |
61 |
dl |
1.47 |
implements Deque<E>, Cloneable, Serializable |
62 |
dl |
1.1 |
{ |
63 |
jsr166 |
1.106 |
/* |
64 |
|
|
* VMs excel at optimizing simple array loops where indices are |
65 |
|
|
* incrementing or decrementing over a valid slice, e.g. |
66 |
|
|
* |
67 |
|
|
* for (int i = start; i < end; i++) ... elements[i] |
68 |
|
|
* |
69 |
|
|
* Because in a circular array, elements are in general stored in |
70 |
|
|
* two disjoint such slices, we help the VM by writing unusual |
71 |
|
|
* nested loops for all traversals over the elements. |
72 |
|
|
*/ |
73 |
|
|
|
74 |
dl |
1.1 |
/** |
75 |
dl |
1.4 |
* The array in which the elements of the deque are stored. |
76 |
jsr166 |
1.75 |
* We guarantee that all array cells not holding deque elements |
77 |
|
|
* are always null. |
78 |
dl |
1.1 |
*/ |
79 |
jsr166 |
1.75 |
transient Object[] elements; |
80 |
dl |
1.1 |
|
81 |
|
|
/** |
82 |
|
|
* The index of the element at the head of the deque (which is the |
83 |
|
|
* element that would be removed by remove() or pop()); or an |
84 |
jsr166 |
1.106 |
* arbitrary number 0 <= head < elements.length equal to tail if |
85 |
|
|
* the deque is empty. |
86 |
dl |
1.1 |
*/ |
87 |
dl |
1.41 |
transient int head; |
88 |
dl |
1.1 |
|
89 |
jsr166 |
1.106 |
/** |
90 |
|
|
* The index at which the next element would be added to the tail |
91 |
|
|
* of the deque (via addLast(E), add(E), or push(E)). |
92 |
|
|
*/ |
93 |
|
|
transient int tail; |
94 |
jsr166 |
1.75 |
|
95 |
dl |
1.1 |
/** |
96 |
jsr166 |
1.75 |
* The maximum size of array to allocate. |
97 |
|
|
* Some VMs reserve some header words in an array. |
98 |
|
|
* Attempts to allocate larger arrays may result in |
99 |
|
|
* OutOfMemoryError: Requested array size exceeds VM limit |
100 |
dl |
1.1 |
*/ |
101 |
jsr166 |
1.75 |
private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8; |
102 |
dl |
1.1 |
|
103 |
|
|
/** |
104 |
jsr166 |
1.75 |
* Increases the capacity of this deque by at least the given amount. |
105 |
|
|
* |
106 |
|
|
* @param needed the required minimum extra capacity; must be positive |
107 |
dl |
1.1 |
*/ |
108 |
jsr166 |
1.106 |
private void grow(int needed) { |
109 |
jsr166 |
1.75 |
// overflow-conscious code |
110 |
jsr166 |
1.91 |
final int oldCapacity = elements.length; |
111 |
jsr166 |
1.75 |
int newCapacity; |
112 |
jsr166 |
1.106 |
// Double capacity if small; else grow by 50% |
113 |
jsr166 |
1.75 |
int jump = (oldCapacity < 64) ? (oldCapacity + 2) : (oldCapacity >> 1); |
114 |
|
|
if (jump < needed |
115 |
|
|
|| (newCapacity = (oldCapacity + jump)) - MAX_ARRAY_SIZE > 0) |
116 |
|
|
newCapacity = newCapacity(needed, jump); |
117 |
|
|
elements = Arrays.copyOf(elements, newCapacity); |
118 |
jsr166 |
1.106 |
// Exceptionally, here tail == head needs to be disambiguated |
119 |
|
|
if (tail < head || (tail == head && elements[head] != null)) { |
120 |
jsr166 |
1.75 |
// wrap around; slide first leg forward to end of array |
121 |
|
|
int newSpace = newCapacity - oldCapacity; |
122 |
|
|
System.arraycopy(elements, head, |
123 |
|
|
elements, head + newSpace, |
124 |
|
|
oldCapacity - head); |
125 |
|
|
Arrays.fill(elements, head, head + newSpace, null); |
126 |
|
|
head += newSpace; |
127 |
|
|
} |
128 |
|
|
// checkInvariants(); |
129 |
|
|
} |
130 |
dl |
1.1 |
|
131 |
jsr166 |
1.75 |
/** Capacity calculation for edge conditions, especially overflow. */ |
132 |
|
|
private int newCapacity(int needed, int jump) { |
133 |
jsr166 |
1.91 |
final int oldCapacity = elements.length, minCapacity; |
134 |
jsr166 |
1.75 |
if ((minCapacity = oldCapacity + needed) - MAX_ARRAY_SIZE > 0) { |
135 |
|
|
if (minCapacity < 0) |
136 |
|
|
throw new IllegalStateException("Sorry, deque too big"); |
137 |
|
|
return Integer.MAX_VALUE; |
138 |
|
|
} |
139 |
|
|
if (needed > jump) |
140 |
|
|
return minCapacity; |
141 |
|
|
return (oldCapacity + jump - MAX_ARRAY_SIZE < 0) |
142 |
|
|
? oldCapacity + jump |
143 |
|
|
: MAX_ARRAY_SIZE; |
144 |
|
|
} |
145 |
dl |
1.1 |
|
146 |
|
|
/** |
147 |
jsr166 |
1.75 |
* Increases the internal storage of this collection, if necessary, |
148 |
|
|
* to ensure that it can hold at least the given number of elements. |
149 |
dl |
1.1 |
* |
150 |
jsr166 |
1.75 |
* @param minCapacity the desired minimum capacity |
151 |
jsr166 |
1.80 |
* @since TBD |
152 |
dl |
1.1 |
*/ |
153 |
jsr166 |
1.80 |
/* public */ void ensureCapacity(int minCapacity) { |
154 |
jsr166 |
1.106 |
int needed; |
155 |
|
|
if ((needed = (minCapacity + 1 - elements.length)) > 0) |
156 |
|
|
grow(needed); |
157 |
jsr166 |
1.75 |
// checkInvariants(); |
158 |
dl |
1.1 |
} |
159 |
|
|
|
160 |
|
|
/** |
161 |
jsr166 |
1.75 |
* Minimizes the internal storage of this collection. |
162 |
jsr166 |
1.80 |
* |
163 |
|
|
* @since TBD |
164 |
dl |
1.1 |
*/ |
165 |
jsr166 |
1.80 |
/* public */ void trimToSize() { |
166 |
jsr166 |
1.106 |
int size; |
167 |
|
|
if ((size = size()) + 1 < elements.length) { |
168 |
|
|
elements = toArray(new Object[size + 1]); |
169 |
jsr166 |
1.75 |
head = 0; |
170 |
jsr166 |
1.106 |
tail = size; |
171 |
jsr166 |
1.75 |
} |
172 |
|
|
// checkInvariants(); |
173 |
dl |
1.1 |
} |
174 |
|
|
|
175 |
|
|
/** |
176 |
dl |
1.4 |
* Constructs an empty array deque with an initial capacity |
177 |
dl |
1.1 |
* sufficient to hold 16 elements. |
178 |
|
|
*/ |
179 |
|
|
public ArrayDeque() { |
180 |
jsr166 |
1.34 |
elements = new Object[16]; |
181 |
dl |
1.1 |
} |
182 |
|
|
|
183 |
|
|
/** |
184 |
|
|
* Constructs an empty array deque with an initial capacity |
185 |
|
|
* sufficient to hold the specified number of elements. |
186 |
|
|
* |
187 |
jsr166 |
1.75 |
* @param numElements lower bound on initial capacity of the deque |
188 |
dl |
1.1 |
*/ |
189 |
|
|
public ArrayDeque(int numElements) { |
190 |
jsr166 |
1.106 |
elements = new Object[Math.max(1, numElements + 1)]; |
191 |
dl |
1.1 |
} |
192 |
|
|
|
193 |
|
|
/** |
194 |
|
|
* Constructs a deque containing the elements of the specified |
195 |
|
|
* collection, in the order they are returned by the collection's |
196 |
|
|
* iterator. (The first element returned by the collection's |
197 |
|
|
* iterator becomes the first element, or <i>front</i> of the |
198 |
|
|
* deque.) |
199 |
|
|
* |
200 |
|
|
* @param c the collection whose elements are to be placed into the deque |
201 |
|
|
* @throws NullPointerException if the specified collection is null |
202 |
|
|
*/ |
203 |
|
|
public ArrayDeque(Collection<? extends E> c) { |
204 |
jsr166 |
1.106 |
elements = new Object[c.size() + 1]; |
205 |
|
|
addAll(c); |
206 |
jsr166 |
1.75 |
} |
207 |
|
|
|
208 |
|
|
/** |
209 |
jsr166 |
1.79 |
* Increments i, mod modulus. |
210 |
|
|
* Precondition and postcondition: 0 <= i < modulus. |
211 |
jsr166 |
1.75 |
*/ |
212 |
jsr166 |
1.79 |
static final int inc(int i, int modulus) { |
213 |
jsr166 |
1.89 |
if (++i >= modulus) i = 0; |
214 |
jsr166 |
1.79 |
return i; |
215 |
jsr166 |
1.75 |
} |
216 |
|
|
|
217 |
|
|
/** |
218 |
jsr166 |
1.79 |
* Decrements i, mod modulus. |
219 |
|
|
* Precondition and postcondition: 0 <= i < modulus. |
220 |
jsr166 |
1.75 |
*/ |
221 |
jsr166 |
1.79 |
static final int dec(int i, int modulus) { |
222 |
jsr166 |
1.89 |
if (--i < 0) i = modulus - 1; |
223 |
jsr166 |
1.75 |
return i; |
224 |
|
|
} |
225 |
|
|
|
226 |
|
|
/** |
227 |
jsr166 |
1.79 |
* Adds i and j, mod modulus. |
228 |
|
|
* Precondition and postcondition: 0 <= i < modulus, 0 <= j <= modulus. |
229 |
jsr166 |
1.75 |
*/ |
230 |
jsr166 |
1.79 |
static final int add(int i, int j, int modulus) { |
231 |
|
|
if ((i += j) - modulus >= 0) i -= modulus; |
232 |
jsr166 |
1.75 |
return i; |
233 |
|
|
} |
234 |
|
|
|
235 |
|
|
/** |
236 |
jsr166 |
1.106 |
* Subtracts j from i, mod modulus. |
237 |
|
|
* Index i must be logically ahead of j. |
238 |
|
|
* Returns the "circular distance" from j to i. |
239 |
|
|
* Precondition and postcondition: 0 <= i < modulus, 0 <= j < modulus. |
240 |
|
|
*/ |
241 |
|
|
static final int sub(int i, int j, int modulus) { |
242 |
|
|
if ((i -= j) < 0) i += modulus; |
243 |
|
|
return i; |
244 |
|
|
} |
245 |
|
|
|
246 |
|
|
/** |
247 |
jsr166 |
1.75 |
* Returns element at array index i. |
248 |
jsr166 |
1.106 |
* This is a slight abuse of generics, accepted by javac. |
249 |
jsr166 |
1.75 |
*/ |
250 |
|
|
@SuppressWarnings("unchecked") |
251 |
jsr166 |
1.106 |
static final <E> E elementAt(Object[] es, int i) { |
252 |
|
|
return (E) es[i]; |
253 |
jsr166 |
1.75 |
} |
254 |
|
|
|
255 |
|
|
/** |
256 |
|
|
* A version of elementAt that checks for null elements. |
257 |
|
|
* This check doesn't catch all possible comodifications, |
258 |
jsr166 |
1.106 |
* but does catch ones that corrupt traversal. |
259 |
jsr166 |
1.75 |
*/ |
260 |
jsr166 |
1.96 |
static final <E> E nonNullElementAt(Object[] es, int i) { |
261 |
|
|
@SuppressWarnings("unchecked") E e = (E) es[i]; |
262 |
jsr166 |
1.75 |
if (e == null) |
263 |
|
|
throw new ConcurrentModificationException(); |
264 |
|
|
return e; |
265 |
dl |
1.1 |
} |
266 |
|
|
|
267 |
|
|
// The main insertion and extraction methods are addFirst, |
268 |
|
|
// addLast, pollFirst, pollLast. The other methods are defined in |
269 |
|
|
// terms of these. |
270 |
|
|
|
271 |
|
|
/** |
272 |
dl |
1.5 |
* Inserts the specified element at the front of this deque. |
273 |
dl |
1.1 |
* |
274 |
jsr166 |
1.9 |
* @param e the element to add |
275 |
|
|
* @throws NullPointerException if the specified element is null |
276 |
dl |
1.1 |
*/ |
277 |
|
|
public void addFirst(E e) { |
278 |
jsr166 |
1.106 |
if (e == null) |
279 |
|
|
throw new NullPointerException(); |
280 |
|
|
final Object[] es = elements; |
281 |
|
|
es[head = dec(head, es.length)] = e; |
282 |
|
|
if (head == tail) |
283 |
|
|
grow(1); |
284 |
jsr166 |
1.83 |
// checkInvariants(); |
285 |
dl |
1.1 |
} |
286 |
|
|
|
287 |
|
|
/** |
288 |
dl |
1.6 |
* Inserts the specified element at the end of this deque. |
289 |
jsr166 |
1.14 |
* |
290 |
|
|
* <p>This method is equivalent to {@link #add}. |
291 |
dl |
1.1 |
* |
292 |
jsr166 |
1.9 |
* @param e the element to add |
293 |
|
|
* @throws NullPointerException if the specified element is null |
294 |
dl |
1.1 |
*/ |
295 |
|
|
public void addLast(E e) { |
296 |
jsr166 |
1.106 |
if (e == null) |
297 |
|
|
throw new NullPointerException(); |
298 |
|
|
final Object[] es = elements; |
299 |
|
|
es[tail] = e; |
300 |
|
|
if (head == (tail = inc(tail, es.length))) |
301 |
|
|
grow(1); |
302 |
jsr166 |
1.83 |
// checkInvariants(); |
303 |
jsr166 |
1.75 |
} |
304 |
|
|
|
305 |
|
|
/** |
306 |
|
|
* Adds all of the elements in the specified collection at the end |
307 |
|
|
* of this deque, as if by calling {@link #addLast} on each one, |
308 |
|
|
* in the order that they are returned by the collection's |
309 |
|
|
* iterator. |
310 |
|
|
* |
311 |
|
|
* @param c the elements to be inserted into this deque |
312 |
|
|
* @return {@code true} if this deque changed as a result of the call |
313 |
|
|
* @throws NullPointerException if the specified collection or any |
314 |
|
|
* of its elements are null |
315 |
|
|
*/ |
316 |
|
|
public boolean addAll(Collection<? extends E> c) { |
317 |
jsr166 |
1.106 |
final int s = size(), needed; |
318 |
|
|
if ((needed = s + c.size() - elements.length + 1) > 0) |
319 |
jsr166 |
1.87 |
grow(needed); |
320 |
jsr166 |
1.111 |
c.forEach(e -> addLast(e)); |
321 |
jsr166 |
1.75 |
// checkInvariants(); |
322 |
jsr166 |
1.106 |
return size() > s; |
323 |
dl |
1.1 |
} |
324 |
|
|
|
325 |
|
|
/** |
326 |
dl |
1.5 |
* Inserts the specified element at the front of this deque. |
327 |
dl |
1.1 |
* |
328 |
jsr166 |
1.9 |
* @param e the element to add |
329 |
jsr166 |
1.40 |
* @return {@code true} (as specified by {@link Deque#offerFirst}) |
330 |
jsr166 |
1.9 |
* @throws NullPointerException if the specified element is null |
331 |
dl |
1.1 |
*/ |
332 |
|
|
public boolean offerFirst(E e) { |
333 |
|
|
addFirst(e); |
334 |
|
|
return true; |
335 |
|
|
} |
336 |
|
|
|
337 |
|
|
/** |
338 |
dl |
1.6 |
* Inserts the specified element at the end of this deque. |
339 |
dl |
1.1 |
* |
340 |
jsr166 |
1.9 |
* @param e the element to add |
341 |
jsr166 |
1.40 |
* @return {@code true} (as specified by {@link Deque#offerLast}) |
342 |
jsr166 |
1.9 |
* @throws NullPointerException if the specified element is null |
343 |
dl |
1.1 |
*/ |
344 |
|
|
public boolean offerLast(E e) { |
345 |
|
|
addLast(e); |
346 |
|
|
return true; |
347 |
|
|
} |
348 |
|
|
|
349 |
|
|
/** |
350 |
jsr166 |
1.9 |
* @throws NoSuchElementException {@inheritDoc} |
351 |
dl |
1.1 |
*/ |
352 |
|
|
public E removeFirst() { |
353 |
jsr166 |
1.84 |
E e = pollFirst(); |
354 |
|
|
if (e == null) |
355 |
dl |
1.1 |
throw new NoSuchElementException(); |
356 |
jsr166 |
1.106 |
// checkInvariants(); |
357 |
jsr166 |
1.84 |
return e; |
358 |
dl |
1.1 |
} |
359 |
|
|
|
360 |
|
|
/** |
361 |
jsr166 |
1.9 |
* @throws NoSuchElementException {@inheritDoc} |
362 |
dl |
1.1 |
*/ |
363 |
|
|
public E removeLast() { |
364 |
jsr166 |
1.84 |
E e = pollLast(); |
365 |
|
|
if (e == null) |
366 |
dl |
1.1 |
throw new NoSuchElementException(); |
367 |
jsr166 |
1.106 |
// checkInvariants(); |
368 |
jsr166 |
1.84 |
return e; |
369 |
dl |
1.1 |
} |
370 |
|
|
|
371 |
jsr166 |
1.9 |
public E pollFirst() { |
372 |
jsr166 |
1.106 |
final Object[] es; |
373 |
|
|
final int h; |
374 |
|
|
E e = elementAt(es = elements, h = head); |
375 |
|
|
if (e != null) { |
376 |
|
|
es[h] = null; |
377 |
|
|
head = inc(h, es.length); |
378 |
|
|
} |
379 |
jsr166 |
1.75 |
// checkInvariants(); |
380 |
|
|
return e; |
381 |
dl |
1.1 |
} |
382 |
|
|
|
383 |
jsr166 |
1.9 |
public E pollLast() { |
384 |
jsr166 |
1.106 |
final Object[] es; |
385 |
|
|
final int t; |
386 |
|
|
E e = elementAt(es = elements, t = dec(tail, es.length)); |
387 |
|
|
if (e != null) |
388 |
|
|
es[tail = t] = null; |
389 |
jsr166 |
1.75 |
// checkInvariants(); |
390 |
|
|
return e; |
391 |
dl |
1.1 |
} |
392 |
|
|
|
393 |
|
|
/** |
394 |
jsr166 |
1.9 |
* @throws NoSuchElementException {@inheritDoc} |
395 |
dl |
1.1 |
*/ |
396 |
|
|
public E getFirst() { |
397 |
jsr166 |
1.106 |
E e = elementAt(elements, head); |
398 |
|
|
if (e == null) |
399 |
|
|
throw new NoSuchElementException(); |
400 |
jsr166 |
1.75 |
// checkInvariants(); |
401 |
jsr166 |
1.106 |
return e; |
402 |
dl |
1.1 |
} |
403 |
|
|
|
404 |
|
|
/** |
405 |
jsr166 |
1.9 |
* @throws NoSuchElementException {@inheritDoc} |
406 |
dl |
1.1 |
*/ |
407 |
|
|
public E getLast() { |
408 |
jsr166 |
1.106 |
final Object[] es = elements; |
409 |
|
|
E e = elementAt(es, dec(tail, es.length)); |
410 |
|
|
if (e == null) |
411 |
|
|
throw new NoSuchElementException(); |
412 |
jsr166 |
1.75 |
// checkInvariants(); |
413 |
jsr166 |
1.106 |
return e; |
414 |
dl |
1.1 |
} |
415 |
|
|
|
416 |
jsr166 |
1.9 |
public E peekFirst() { |
417 |
jsr166 |
1.75 |
// checkInvariants(); |
418 |
jsr166 |
1.106 |
return elementAt(elements, head); |
419 |
jsr166 |
1.9 |
} |
420 |
|
|
|
421 |
|
|
public E peekLast() { |
422 |
jsr166 |
1.75 |
// checkInvariants(); |
423 |
jsr166 |
1.106 |
final Object[] es; |
424 |
|
|
return elementAt(es = elements, dec(tail, es.length)); |
425 |
jsr166 |
1.9 |
} |
426 |
|
|
|
427 |
dl |
1.1 |
/** |
428 |
|
|
* Removes the first occurrence of the specified element in this |
429 |
jsr166 |
1.9 |
* deque (when traversing the deque from head to tail). |
430 |
|
|
* If the deque does not contain the element, it is unchanged. |
431 |
jsr166 |
1.40 |
* More formally, removes the first element {@code e} such that |
432 |
|
|
* {@code o.equals(e)} (if such an element exists). |
433 |
|
|
* Returns {@code true} if this deque contained the specified element |
434 |
jsr166 |
1.12 |
* (or equivalently, if this deque changed as a result of the call). |
435 |
dl |
1.1 |
* |
436 |
dl |
1.5 |
* @param o element to be removed from this deque, if present |
437 |
jsr166 |
1.40 |
* @return {@code true} if the deque contained the specified element |
438 |
dl |
1.1 |
*/ |
439 |
dl |
1.5 |
public boolean removeFirstOccurrence(Object o) { |
440 |
jsr166 |
1.58 |
if (o != null) { |
441 |
jsr166 |
1.99 |
final Object[] es = elements; |
442 |
jsr166 |
1.106 |
for (int i = head, end = tail, to = (i <= end) ? end : es.length; |
443 |
|
|
; i = 0, to = end) { |
444 |
jsr166 |
1.92 |
for (; i < to; i++) |
445 |
jsr166 |
1.99 |
if (o.equals(es[i])) { |
446 |
jsr166 |
1.89 |
delete(i); |
447 |
|
|
return true; |
448 |
|
|
} |
449 |
jsr166 |
1.106 |
if (to == end) break; |
450 |
dl |
1.1 |
} |
451 |
|
|
} |
452 |
|
|
return false; |
453 |
|
|
} |
454 |
|
|
|
455 |
|
|
/** |
456 |
|
|
* Removes the last occurrence of the specified element in this |
457 |
jsr166 |
1.9 |
* deque (when traversing the deque from head to tail). |
458 |
|
|
* If the deque does not contain the element, it is unchanged. |
459 |
jsr166 |
1.40 |
* More formally, removes the last element {@code e} such that |
460 |
|
|
* {@code o.equals(e)} (if such an element exists). |
461 |
|
|
* Returns {@code true} if this deque contained the specified element |
462 |
jsr166 |
1.12 |
* (or equivalently, if this deque changed as a result of the call). |
463 |
dl |
1.1 |
* |
464 |
dl |
1.5 |
* @param o element to be removed from this deque, if present |
465 |
jsr166 |
1.40 |
* @return {@code true} if the deque contained the specified element |
466 |
dl |
1.1 |
*/ |
467 |
dl |
1.5 |
public boolean removeLastOccurrence(Object o) { |
468 |
jsr166 |
1.59 |
if (o != null) { |
469 |
jsr166 |
1.99 |
final Object[] es = elements; |
470 |
jsr166 |
1.107 |
for (int i = tail, end = head, to = (i >= end) ? end : 0; |
471 |
|
|
; i = es.length, to = end) { |
472 |
jsr166 |
1.110 |
for (i--; i > to - 1; i--) |
473 |
jsr166 |
1.99 |
if (o.equals(es[i])) { |
474 |
jsr166 |
1.89 |
delete(i); |
475 |
|
|
return true; |
476 |
|
|
} |
477 |
jsr166 |
1.106 |
if (to == end) break; |
478 |
dl |
1.1 |
} |
479 |
|
|
} |
480 |
|
|
return false; |
481 |
|
|
} |
482 |
|
|
|
483 |
|
|
// *** Queue methods *** |
484 |
|
|
|
485 |
|
|
/** |
486 |
dl |
1.6 |
* Inserts the specified element at the end of this deque. |
487 |
dl |
1.1 |
* |
488 |
|
|
* <p>This method is equivalent to {@link #addLast}. |
489 |
|
|
* |
490 |
jsr166 |
1.9 |
* @param e the element to add |
491 |
jsr166 |
1.40 |
* @return {@code true} (as specified by {@link Collection#add}) |
492 |
jsr166 |
1.9 |
* @throws NullPointerException if the specified element is null |
493 |
dl |
1.1 |
*/ |
494 |
|
|
public boolean add(E e) { |
495 |
|
|
addLast(e); |
496 |
|
|
return true; |
497 |
|
|
} |
498 |
|
|
|
499 |
|
|
/** |
500 |
jsr166 |
1.9 |
* Inserts the specified element at the end of this deque. |
501 |
dl |
1.1 |
* |
502 |
jsr166 |
1.9 |
* <p>This method is equivalent to {@link #offerLast}. |
503 |
dl |
1.1 |
* |
504 |
jsr166 |
1.9 |
* @param e the element to add |
505 |
jsr166 |
1.40 |
* @return {@code true} (as specified by {@link Queue#offer}) |
506 |
jsr166 |
1.9 |
* @throws NullPointerException if the specified element is null |
507 |
dl |
1.1 |
*/ |
508 |
jsr166 |
1.9 |
public boolean offer(E e) { |
509 |
|
|
return offerLast(e); |
510 |
dl |
1.1 |
} |
511 |
|
|
|
512 |
|
|
/** |
513 |
|
|
* Retrieves and removes the head of the queue represented by this deque. |
514 |
jsr166 |
1.15 |
* |
515 |
|
|
* This method differs from {@link #poll poll} only in that it throws an |
516 |
jsr166 |
1.9 |
* exception if this deque is empty. |
517 |
dl |
1.1 |
* |
518 |
|
|
* <p>This method is equivalent to {@link #removeFirst}. |
519 |
|
|
* |
520 |
|
|
* @return the head of the queue represented by this deque |
521 |
jsr166 |
1.9 |
* @throws NoSuchElementException {@inheritDoc} |
522 |
dl |
1.1 |
*/ |
523 |
|
|
public E remove() { |
524 |
|
|
return removeFirst(); |
525 |
|
|
} |
526 |
|
|
|
527 |
|
|
/** |
528 |
jsr166 |
1.9 |
* Retrieves and removes the head of the queue represented by this deque |
529 |
|
|
* (in other words, the first element of this deque), or returns |
530 |
jsr166 |
1.40 |
* {@code null} if this deque is empty. |
531 |
dl |
1.1 |
* |
532 |
jsr166 |
1.9 |
* <p>This method is equivalent to {@link #pollFirst}. |
533 |
dl |
1.1 |
* |
534 |
|
|
* @return the head of the queue represented by this deque, or |
535 |
jsr166 |
1.40 |
* {@code null} if this deque is empty |
536 |
dl |
1.1 |
*/ |
537 |
jsr166 |
1.9 |
public E poll() { |
538 |
|
|
return pollFirst(); |
539 |
dl |
1.1 |
} |
540 |
|
|
|
541 |
|
|
/** |
542 |
|
|
* Retrieves, but does not remove, the head of the queue represented by |
543 |
jsr166 |
1.15 |
* this deque. This method differs from {@link #peek peek} only in |
544 |
|
|
* that it throws an exception if this deque is empty. |
545 |
dl |
1.1 |
* |
546 |
jsr166 |
1.8 |
* <p>This method is equivalent to {@link #getFirst}. |
547 |
dl |
1.1 |
* |
548 |
|
|
* @return the head of the queue represented by this deque |
549 |
jsr166 |
1.9 |
* @throws NoSuchElementException {@inheritDoc} |
550 |
dl |
1.1 |
*/ |
551 |
|
|
public E element() { |
552 |
|
|
return getFirst(); |
553 |
|
|
} |
554 |
|
|
|
555 |
jsr166 |
1.9 |
/** |
556 |
|
|
* Retrieves, but does not remove, the head of the queue represented by |
557 |
jsr166 |
1.40 |
* this deque, or returns {@code null} if this deque is empty. |
558 |
jsr166 |
1.9 |
* |
559 |
|
|
* <p>This method is equivalent to {@link #peekFirst}. |
560 |
|
|
* |
561 |
|
|
* @return the head of the queue represented by this deque, or |
562 |
jsr166 |
1.40 |
* {@code null} if this deque is empty |
563 |
jsr166 |
1.9 |
*/ |
564 |
|
|
public E peek() { |
565 |
|
|
return peekFirst(); |
566 |
|
|
} |
567 |
|
|
|
568 |
dl |
1.1 |
// *** Stack methods *** |
569 |
|
|
|
570 |
|
|
/** |
571 |
|
|
* Pushes an element onto the stack represented by this deque. In other |
572 |
dl |
1.5 |
* words, inserts the element at the front of this deque. |
573 |
dl |
1.1 |
* |
574 |
|
|
* <p>This method is equivalent to {@link #addFirst}. |
575 |
|
|
* |
576 |
|
|
* @param e the element to push |
577 |
jsr166 |
1.9 |
* @throws NullPointerException if the specified element is null |
578 |
dl |
1.1 |
*/ |
579 |
|
|
public void push(E e) { |
580 |
|
|
addFirst(e); |
581 |
|
|
} |
582 |
|
|
|
583 |
|
|
/** |
584 |
|
|
* Pops an element from the stack represented by this deque. In other |
585 |
dl |
1.2 |
* words, removes and returns the first element of this deque. |
586 |
dl |
1.1 |
* |
587 |
|
|
* <p>This method is equivalent to {@link #removeFirst()}. |
588 |
|
|
* |
589 |
|
|
* @return the element at the front of this deque (which is the top |
590 |
jsr166 |
1.9 |
* of the stack represented by this deque) |
591 |
|
|
* @throws NoSuchElementException {@inheritDoc} |
592 |
dl |
1.1 |
*/ |
593 |
|
|
public E pop() { |
594 |
|
|
return removeFirst(); |
595 |
|
|
} |
596 |
|
|
|
597 |
|
|
/** |
598 |
jsr166 |
1.75 |
* Removes the element at the specified position in the elements array. |
599 |
|
|
* This can result in forward or backwards motion of array elements. |
600 |
|
|
* We optimize for least element motion. |
601 |
dl |
1.1 |
* |
602 |
dl |
1.5 |
* <p>This method is called delete rather than remove to emphasize |
603 |
jsr166 |
1.9 |
* that its semantics differ from those of {@link List#remove(int)}. |
604 |
dl |
1.5 |
* |
605 |
jsr166 |
1.106 |
* @return true if elements near tail moved backwards |
606 |
dl |
1.1 |
*/ |
607 |
jsr166 |
1.71 |
boolean delete(int i) { |
608 |
jsr166 |
1.75 |
// checkInvariants(); |
609 |
jsr166 |
1.99 |
final Object[] es = elements; |
610 |
|
|
final int capacity = es.length; |
611 |
jsr166 |
1.30 |
final int h = head; |
612 |
jsr166 |
1.106 |
// number of elements before to-be-deleted elt |
613 |
|
|
final int front = sub(i, h, capacity); |
614 |
|
|
final int back = size() - front - 1; // number of elements after |
615 |
jsr166 |
1.30 |
if (front < back) { |
616 |
jsr166 |
1.75 |
// move front elements forwards |
617 |
jsr166 |
1.30 |
if (h <= i) { |
618 |
jsr166 |
1.99 |
System.arraycopy(es, h, es, h + 1, front); |
619 |
jsr166 |
1.30 |
} else { // Wrap around |
620 |
jsr166 |
1.99 |
System.arraycopy(es, 0, es, 1, i); |
621 |
|
|
es[0] = es[capacity - 1]; |
622 |
|
|
System.arraycopy(es, h, es, h + 1, front - (i + 1)); |
623 |
jsr166 |
1.30 |
} |
624 |
jsr166 |
1.99 |
es[h] = null; |
625 |
jsr166 |
1.106 |
head = inc(h, capacity); |
626 |
jsr166 |
1.75 |
// checkInvariants(); |
627 |
jsr166 |
1.30 |
return false; |
628 |
|
|
} else { |
629 |
jsr166 |
1.75 |
// move back elements backwards |
630 |
jsr166 |
1.106 |
tail = dec(tail, capacity); |
631 |
jsr166 |
1.75 |
if (i <= tail) { |
632 |
jsr166 |
1.99 |
System.arraycopy(es, i + 1, es, i, back); |
633 |
jsr166 |
1.30 |
} else { // Wrap around |
634 |
jsr166 |
1.75 |
int firstLeg = capacity - (i + 1); |
635 |
jsr166 |
1.99 |
System.arraycopy(es, i + 1, es, i, firstLeg); |
636 |
|
|
es[capacity - 1] = es[0]; |
637 |
|
|
System.arraycopy(es, 1, es, 0, back - firstLeg - 1); |
638 |
jsr166 |
1.30 |
} |
639 |
jsr166 |
1.99 |
es[tail] = null; |
640 |
jsr166 |
1.75 |
// checkInvariants(); |
641 |
jsr166 |
1.30 |
return true; |
642 |
|
|
} |
643 |
dl |
1.23 |
} |
644 |
|
|
|
645 |
dl |
1.1 |
// *** Collection Methods *** |
646 |
|
|
|
647 |
|
|
/** |
648 |
|
|
* Returns the number of elements in this deque. |
649 |
|
|
* |
650 |
|
|
* @return the number of elements in this deque |
651 |
|
|
*/ |
652 |
|
|
public int size() { |
653 |
jsr166 |
1.106 |
return sub(tail, head, elements.length); |
654 |
dl |
1.1 |
} |
655 |
|
|
|
656 |
|
|
/** |
657 |
jsr166 |
1.40 |
* Returns {@code true} if this deque contains no elements. |
658 |
dl |
1.1 |
* |
659 |
jsr166 |
1.40 |
* @return {@code true} if this deque contains no elements |
660 |
dl |
1.1 |
*/ |
661 |
|
|
public boolean isEmpty() { |
662 |
jsr166 |
1.106 |
return head == tail; |
663 |
dl |
1.1 |
} |
664 |
|
|
|
665 |
|
|
/** |
666 |
|
|
* Returns an iterator over the elements in this deque. The elements |
667 |
|
|
* will be ordered from first (head) to last (tail). This is the same |
668 |
|
|
* order that elements would be dequeued (via successive calls to |
669 |
|
|
* {@link #remove} or popped (via successive calls to {@link #pop}). |
670 |
dl |
1.5 |
* |
671 |
jsr166 |
1.18 |
* @return an iterator over the elements in this deque |
672 |
dl |
1.1 |
*/ |
673 |
|
|
public Iterator<E> iterator() { |
674 |
|
|
return new DeqIterator(); |
675 |
|
|
} |
676 |
|
|
|
677 |
dl |
1.16 |
public Iterator<E> descendingIterator() { |
678 |
|
|
return new DescendingIterator(); |
679 |
|
|
} |
680 |
|
|
|
681 |
dl |
1.1 |
private class DeqIterator implements Iterator<E> { |
682 |
jsr166 |
1.75 |
/** Index of element to be returned by subsequent call to next. */ |
683 |
|
|
int cursor; |
684 |
dl |
1.1 |
|
685 |
jsr166 |
1.75 |
/** Number of elements yet to be returned. */ |
686 |
jsr166 |
1.106 |
int remaining = size(); |
687 |
dl |
1.1 |
|
688 |
|
|
/** |
689 |
|
|
* Index of element returned by most recent call to next. |
690 |
|
|
* Reset to -1 if element is deleted by a call to remove. |
691 |
|
|
*/ |
692 |
jsr166 |
1.75 |
int lastRet = -1; |
693 |
dl |
1.1 |
|
694 |
jsr166 |
1.75 |
DeqIterator() { cursor = head; } |
695 |
|
|
|
696 |
|
|
public final boolean hasNext() { |
697 |
|
|
return remaining > 0; |
698 |
|
|
} |
699 |
|
|
|
700 |
jsr166 |
1.81 |
public E next() { |
701 |
jsr166 |
1.91 |
if (remaining <= 0) |
702 |
dl |
1.1 |
throw new NoSuchElementException(); |
703 |
jsr166 |
1.99 |
final Object[] es = elements; |
704 |
|
|
E e = nonNullElementAt(es, cursor); |
705 |
dl |
1.1 |
lastRet = cursor; |
706 |
jsr166 |
1.106 |
cursor = inc(cursor, es.length); |
707 |
jsr166 |
1.75 |
remaining--; |
708 |
|
|
return e; |
709 |
dl |
1.1 |
} |
710 |
|
|
|
711 |
jsr166 |
1.81 |
void postDelete(boolean leftShifted) { |
712 |
|
|
if (leftShifted) |
713 |
jsr166 |
1.106 |
cursor = dec(cursor, elements.length); |
714 |
jsr166 |
1.81 |
} |
715 |
|
|
|
716 |
jsr166 |
1.75 |
public final void remove() { |
717 |
dl |
1.1 |
if (lastRet < 0) |
718 |
|
|
throw new IllegalStateException(); |
719 |
jsr166 |
1.81 |
postDelete(delete(lastRet)); |
720 |
dl |
1.1 |
lastRet = -1; |
721 |
|
|
} |
722 |
jsr166 |
1.68 |
|
723 |
jsr166 |
1.81 |
public void forEachRemaining(Consumer<? super E> action) { |
724 |
jsr166 |
1.98 |
Objects.requireNonNull(action); |
725 |
jsr166 |
1.106 |
int r; |
726 |
|
|
if ((r = remaining) <= 0) |
727 |
|
|
return; |
728 |
|
|
remaining = 0; |
729 |
|
|
final Object[] es = elements; |
730 |
|
|
if (es[cursor] == null || sub(tail, cursor, es.length) != r) |
731 |
|
|
throw new ConcurrentModificationException(); |
732 |
|
|
for (int i = cursor, end = tail, to = (i <= end) ? end : es.length; |
733 |
|
|
; i = 0, to = end) { |
734 |
|
|
for (; i < to; i++) |
735 |
|
|
action.accept(elementAt(es, i)); |
736 |
|
|
if (to == end) { |
737 |
|
|
if (end != tail) |
738 |
|
|
throw new ConcurrentModificationException(); |
739 |
|
|
lastRet = dec(end, es.length); |
740 |
|
|
break; |
741 |
|
|
} |
742 |
jsr166 |
1.89 |
} |
743 |
jsr166 |
1.68 |
} |
744 |
dl |
1.1 |
} |
745 |
|
|
|
746 |
jsr166 |
1.75 |
private class DescendingIterator extends DeqIterator { |
747 |
jsr166 |
1.109 |
DescendingIterator() { cursor = dec(tail, elements.length); } |
748 |
jsr166 |
1.75 |
|
749 |
jsr166 |
1.81 |
public final E next() { |
750 |
jsr166 |
1.91 |
if (remaining <= 0) |
751 |
jsr166 |
1.81 |
throw new NoSuchElementException(); |
752 |
jsr166 |
1.99 |
final Object[] es = elements; |
753 |
|
|
E e = nonNullElementAt(es, cursor); |
754 |
jsr166 |
1.81 |
lastRet = cursor; |
755 |
jsr166 |
1.106 |
cursor = dec(cursor, es.length); |
756 |
jsr166 |
1.81 |
remaining--; |
757 |
|
|
return e; |
758 |
jsr166 |
1.75 |
} |
759 |
|
|
|
760 |
jsr166 |
1.81 |
void postDelete(boolean leftShifted) { |
761 |
|
|
if (!leftShifted) |
762 |
jsr166 |
1.106 |
cursor = inc(cursor, elements.length); |
763 |
jsr166 |
1.81 |
} |
764 |
|
|
|
765 |
|
|
public final void forEachRemaining(Consumer<? super E> action) { |
766 |
jsr166 |
1.98 |
Objects.requireNonNull(action); |
767 |
jsr166 |
1.106 |
int r; |
768 |
|
|
if ((r = remaining) <= 0) |
769 |
|
|
return; |
770 |
|
|
remaining = 0; |
771 |
|
|
final Object[] es = elements; |
772 |
|
|
if (es[cursor] == null || sub(cursor, head, es.length) + 1 != r) |
773 |
|
|
throw new ConcurrentModificationException(); |
774 |
jsr166 |
1.108 |
for (int i = cursor, end = head, to = (i >= end) ? end : 0; |
775 |
jsr166 |
1.106 |
; i = es.length - 1, to = end) { |
776 |
jsr166 |
1.110 |
// hotspot generates faster code than for: i >= to ! |
777 |
|
|
for (; i > to - 1; i--) |
778 |
jsr166 |
1.106 |
action.accept(elementAt(es, i)); |
779 |
|
|
if (to == end) { |
780 |
jsr166 |
1.108 |
if (end != head) |
781 |
jsr166 |
1.106 |
throw new ConcurrentModificationException(); |
782 |
|
|
lastRet = head; |
783 |
|
|
break; |
784 |
jsr166 |
1.98 |
} |
785 |
jsr166 |
1.89 |
} |
786 |
jsr166 |
1.75 |
} |
787 |
|
|
} |
788 |
|
|
|
789 |
jsr166 |
1.52 |
/** |
790 |
jsr166 |
1.75 |
* Creates a <em><a href="Spliterator.html#binding">late-binding</a></em> |
791 |
|
|
* and <em>fail-fast</em> {@link Spliterator} over the elements in this |
792 |
|
|
* deque. |
793 |
|
|
* |
794 |
|
|
* <p>The {@code Spliterator} reports {@link Spliterator#SIZED}, |
795 |
|
|
* {@link Spliterator#SUBSIZED}, {@link Spliterator#ORDERED}, and |
796 |
|
|
* {@link Spliterator#NONNULL}. Overriding implementations should document |
797 |
|
|
* the reporting of additional characteristic values. |
798 |
|
|
* |
799 |
|
|
* @return a {@code Spliterator} over the elements in this deque |
800 |
|
|
* @since 1.8 |
801 |
jsr166 |
1.52 |
*/ |
802 |
jsr166 |
1.75 |
public Spliterator<E> spliterator() { |
803 |
jsr166 |
1.106 |
return new DeqSpliterator(); |
804 |
jsr166 |
1.75 |
} |
805 |
|
|
|
806 |
jsr166 |
1.106 |
final class DeqSpliterator implements Spliterator<E> { |
807 |
|
|
private int fence; // -1 until first use |
808 |
|
|
private int cursor; // current index, modified on traverse/split |
809 |
jsr166 |
1.75 |
|
810 |
jsr166 |
1.76 |
/** Constructs late-binding spliterator over all elements. */ |
811 |
jsr166 |
1.106 |
DeqSpliterator() { |
812 |
|
|
this.fence = -1; |
813 |
jsr166 |
1.76 |
} |
814 |
|
|
|
815 |
jsr166 |
1.106 |
/** Constructs spliterator over the given range. */ |
816 |
|
|
DeqSpliterator(int origin, int fence) { |
817 |
|
|
this.cursor = origin; |
818 |
|
|
this.fence = fence; |
819 |
jsr166 |
1.75 |
} |
820 |
|
|
|
821 |
jsr166 |
1.106 |
/** Ensures late-binding initialization; then returns fence. */ |
822 |
|
|
private int getFence() { // force initialization |
823 |
|
|
int t; |
824 |
|
|
if ((t = fence) < 0) { |
825 |
|
|
t = fence = tail; |
826 |
jsr166 |
1.76 |
cursor = head; |
827 |
|
|
} |
828 |
jsr166 |
1.106 |
return t; |
829 |
jsr166 |
1.76 |
} |
830 |
|
|
|
831 |
jsr166 |
1.106 |
public DeqSpliterator trySplit() { |
832 |
|
|
final Object[] es = elements; |
833 |
|
|
final int i, n; |
834 |
|
|
return ((n = sub(getFence(), i = cursor, es.length) >> 1) <= 0) |
835 |
|
|
? null |
836 |
|
|
: new DeqSpliterator(i, cursor = add(i, n, es.length)); |
837 |
jsr166 |
1.75 |
} |
838 |
dl |
1.16 |
|
839 |
jsr166 |
1.75 |
public void forEachRemaining(Consumer<? super E> action) { |
840 |
jsr166 |
1.106 |
if (action == null) |
841 |
|
|
throw new NullPointerException(); |
842 |
|
|
final int end = getFence(), cursor = this.cursor; |
843 |
|
|
final Object[] es = elements; |
844 |
|
|
if (cursor != end) { |
845 |
|
|
this.cursor = end; |
846 |
|
|
// null check at both ends of range is sufficient |
847 |
|
|
if (es[cursor] == null || es[dec(end, es.length)] == null) |
848 |
|
|
throw new ConcurrentModificationException(); |
849 |
|
|
for (int i = cursor, to = (i <= end) ? end : es.length; |
850 |
|
|
; i = 0, to = end) { |
851 |
|
|
for (; i < to; i++) |
852 |
|
|
action.accept(elementAt(es, i)); |
853 |
|
|
if (to == end) break; |
854 |
|
|
} |
855 |
|
|
} |
856 |
dl |
1.16 |
} |
857 |
|
|
|
858 |
jsr166 |
1.75 |
public boolean tryAdvance(Consumer<? super E> action) { |
859 |
jsr166 |
1.106 |
if (action == null) |
860 |
|
|
throw new NullPointerException(); |
861 |
|
|
int t, i; |
862 |
|
|
if ((t = fence) < 0) t = getFence(); |
863 |
|
|
if (t == (i = cursor)) |
864 |
jsr166 |
1.75 |
return false; |
865 |
jsr166 |
1.106 |
final Object[] es; |
866 |
|
|
action.accept(nonNullElementAt(es = elements, i)); |
867 |
|
|
cursor = inc(i, es.length); |
868 |
jsr166 |
1.75 |
return true; |
869 |
|
|
} |
870 |
|
|
|
871 |
|
|
public long estimateSize() { |
872 |
jsr166 |
1.106 |
return sub(getFence(), cursor, elements.length); |
873 |
jsr166 |
1.75 |
} |
874 |
|
|
|
875 |
|
|
public int characteristics() { |
876 |
|
|
return Spliterator.NONNULL |
877 |
|
|
| Spliterator.ORDERED |
878 |
|
|
| Spliterator.SIZED |
879 |
|
|
| Spliterator.SUBSIZED; |
880 |
dl |
1.16 |
} |
881 |
jsr166 |
1.75 |
} |
882 |
dl |
1.16 |
|
883 |
jsr166 |
1.75 |
public void forEach(Consumer<? super E> action) { |
884 |
|
|
Objects.requireNonNull(action); |
885 |
jsr166 |
1.99 |
final Object[] es = elements; |
886 |
jsr166 |
1.106 |
for (int i = head, end = tail, to = (i <= end) ? end : es.length; |
887 |
|
|
; i = 0, to = end) { |
888 |
jsr166 |
1.92 |
for (; i < to; i++) |
889 |
jsr166 |
1.106 |
action.accept(elementAt(es, i)); |
890 |
|
|
if (to == end) { |
891 |
|
|
if (end != tail) throw new ConcurrentModificationException(); |
892 |
|
|
break; |
893 |
|
|
} |
894 |
jsr166 |
1.89 |
} |
895 |
jsr166 |
1.75 |
// checkInvariants(); |
896 |
|
|
} |
897 |
|
|
|
898 |
|
|
/** |
899 |
|
|
* Replaces each element of this deque with the result of applying the |
900 |
|
|
* operator to that element, as specified by {@link List#replaceAll}. |
901 |
|
|
* |
902 |
|
|
* @param operator the operator to apply to each element |
903 |
jsr166 |
1.80 |
* @since TBD |
904 |
jsr166 |
1.75 |
*/ |
905 |
jsr166 |
1.80 |
/* public */ void replaceAll(UnaryOperator<E> operator) { |
906 |
jsr166 |
1.75 |
Objects.requireNonNull(operator); |
907 |
jsr166 |
1.99 |
final Object[] es = elements; |
908 |
jsr166 |
1.106 |
for (int i = head, end = tail, to = (i <= end) ? end : es.length; |
909 |
|
|
; i = 0, to = end) { |
910 |
jsr166 |
1.92 |
for (; i < to; i++) |
911 |
jsr166 |
1.106 |
es[i] = operator.apply(elementAt(es, i)); |
912 |
|
|
if (to == end) { |
913 |
|
|
if (end != tail) throw new ConcurrentModificationException(); |
914 |
|
|
break; |
915 |
|
|
} |
916 |
jsr166 |
1.89 |
} |
917 |
jsr166 |
1.75 |
// checkInvariants(); |
918 |
|
|
} |
919 |
|
|
|
920 |
|
|
/** |
921 |
|
|
* @throws NullPointerException {@inheritDoc} |
922 |
|
|
*/ |
923 |
|
|
public boolean removeIf(Predicate<? super E> filter) { |
924 |
|
|
Objects.requireNonNull(filter); |
925 |
|
|
return bulkRemove(filter); |
926 |
|
|
} |
927 |
|
|
|
928 |
|
|
/** |
929 |
|
|
* @throws NullPointerException {@inheritDoc} |
930 |
|
|
*/ |
931 |
|
|
public boolean removeAll(Collection<?> c) { |
932 |
|
|
Objects.requireNonNull(c); |
933 |
|
|
return bulkRemove(e -> c.contains(e)); |
934 |
|
|
} |
935 |
|
|
|
936 |
|
|
/** |
937 |
|
|
* @throws NullPointerException {@inheritDoc} |
938 |
|
|
*/ |
939 |
|
|
public boolean retainAll(Collection<?> c) { |
940 |
|
|
Objects.requireNonNull(c); |
941 |
|
|
return bulkRemove(e -> !c.contains(e)); |
942 |
|
|
} |
943 |
|
|
|
944 |
|
|
/** Implementation of bulk remove methods. */ |
945 |
|
|
private boolean bulkRemove(Predicate<? super E> filter) { |
946 |
|
|
// checkInvariants(); |
947 |
jsr166 |
1.99 |
final Object[] es = elements; |
948 |
jsr166 |
1.106 |
// Optimize for initial run of survivors |
949 |
|
|
for (int i = head, end = tail, to = (i <= end) ? end : es.length; |
950 |
|
|
; i = 0, to = end) { |
951 |
jsr166 |
1.104 |
for (; i < to; i++) |
952 |
jsr166 |
1.106 |
if (filter.test(elementAt(es, i))) |
953 |
|
|
return bulkRemoveModified(filter, i, to); |
954 |
|
|
if (to == end) { |
955 |
|
|
if (end != tail) throw new ConcurrentModificationException(); |
956 |
|
|
break; |
957 |
|
|
} |
958 |
jsr166 |
1.104 |
} |
959 |
jsr166 |
1.106 |
return false; |
960 |
jsr166 |
1.104 |
} |
961 |
|
|
|
962 |
|
|
/** |
963 |
|
|
* Helper for bulkRemove, in case of at least one deletion. |
964 |
|
|
* @param i valid index of first element to be deleted |
965 |
|
|
*/ |
966 |
jsr166 |
1.106 |
private boolean bulkRemoveModified( |
967 |
|
|
Predicate<? super E> filter, int i, int to) { |
968 |
jsr166 |
1.104 |
final Object[] es = elements; |
969 |
jsr166 |
1.99 |
final int capacity = es.length; |
970 |
jsr166 |
1.106 |
// a two-finger algorithm, with hare i reading, tortoise j writing |
971 |
jsr166 |
1.104 |
int j = i++; |
972 |
jsr166 |
1.106 |
final int end = tail; |
973 |
jsr166 |
1.75 |
try { |
974 |
jsr166 |
1.106 |
for (;; j = 0) { // j rejoins i on second leg |
975 |
jsr166 |
1.104 |
E e; |
976 |
|
|
// In this loop, i and j are on the same leg, with i > j |
977 |
|
|
for (; i < to; i++) |
978 |
jsr166 |
1.106 |
if (!filter.test(e = elementAt(es, i))) |
979 |
jsr166 |
1.104 |
es[j++] = e; |
980 |
jsr166 |
1.106 |
if (to == end) break; |
981 |
jsr166 |
1.104 |
// In this loop, j is on the first leg, i on the second |
982 |
jsr166 |
1.106 |
for (i = 0, to = end; i < to && j < capacity; i++) |
983 |
|
|
if (!filter.test(e = elementAt(es, i))) |
984 |
jsr166 |
1.104 |
es[j++] = e; |
985 |
jsr166 |
1.106 |
if (i >= to) { |
986 |
|
|
if (j == capacity) j = 0; // "corner" case |
987 |
|
|
break; |
988 |
|
|
} |
989 |
jsr166 |
1.104 |
} |
990 |
jsr166 |
1.106 |
return true; |
991 |
jsr166 |
1.104 |
} catch (Throwable ex) { |
992 |
|
|
// copy remaining elements |
993 |
jsr166 |
1.106 |
for (; i != end; i = inc(i, capacity), j = inc(j, capacity)) |
994 |
jsr166 |
1.104 |
es[j] = es[i]; |
995 |
jsr166 |
1.106 |
throw ex; |
996 |
|
|
} finally { |
997 |
|
|
if (end != tail) throw new ConcurrentModificationException(); |
998 |
|
|
circularClear(es, tail = j, end); |
999 |
jsr166 |
1.104 |
// checkInvariants(); |
1000 |
dl |
1.16 |
} |
1001 |
|
|
} |
1002 |
|
|
|
1003 |
dl |
1.1 |
/** |
1004 |
jsr166 |
1.40 |
* Returns {@code true} if this deque contains the specified element. |
1005 |
|
|
* More formally, returns {@code true} if and only if this deque contains |
1006 |
|
|
* at least one element {@code e} such that {@code o.equals(e)}. |
1007 |
dl |
1.1 |
* |
1008 |
|
|
* @param o object to be checked for containment in this deque |
1009 |
jsr166 |
1.40 |
* @return {@code true} if this deque contains the specified element |
1010 |
dl |
1.1 |
*/ |
1011 |
|
|
public boolean contains(Object o) { |
1012 |
jsr166 |
1.58 |
if (o != null) { |
1013 |
jsr166 |
1.99 |
final Object[] es = elements; |
1014 |
jsr166 |
1.106 |
for (int i = head, end = tail, to = (i <= end) ? end : es.length; |
1015 |
|
|
; i = 0, to = end) { |
1016 |
jsr166 |
1.92 |
for (; i < to; i++) |
1017 |
jsr166 |
1.99 |
if (o.equals(es[i])) |
1018 |
jsr166 |
1.89 |
return true; |
1019 |
jsr166 |
1.106 |
if (to == end) break; |
1020 |
jsr166 |
1.89 |
} |
1021 |
dl |
1.1 |
} |
1022 |
|
|
return false; |
1023 |
|
|
} |
1024 |
|
|
|
1025 |
|
|
/** |
1026 |
|
|
* Removes a single instance of the specified element from this deque. |
1027 |
jsr166 |
1.9 |
* If the deque does not contain the element, it is unchanged. |
1028 |
jsr166 |
1.40 |
* More formally, removes the first element {@code e} such that |
1029 |
|
|
* {@code o.equals(e)} (if such an element exists). |
1030 |
|
|
* Returns {@code true} if this deque contained the specified element |
1031 |
jsr166 |
1.12 |
* (or equivalently, if this deque changed as a result of the call). |
1032 |
jsr166 |
1.9 |
* |
1033 |
jsr166 |
1.46 |
* <p>This method is equivalent to {@link #removeFirstOccurrence(Object)}. |
1034 |
dl |
1.1 |
* |
1035 |
jsr166 |
1.9 |
* @param o element to be removed from this deque, if present |
1036 |
jsr166 |
1.40 |
* @return {@code true} if this deque contained the specified element |
1037 |
dl |
1.1 |
*/ |
1038 |
jsr166 |
1.9 |
public boolean remove(Object o) { |
1039 |
|
|
return removeFirstOccurrence(o); |
1040 |
dl |
1.1 |
} |
1041 |
|
|
|
1042 |
|
|
/** |
1043 |
|
|
* Removes all of the elements from this deque. |
1044 |
jsr166 |
1.7 |
* The deque will be empty after this call returns. |
1045 |
dl |
1.1 |
*/ |
1046 |
|
|
public void clear() { |
1047 |
jsr166 |
1.106 |
circularClear(elements, head, tail); |
1048 |
|
|
head = tail = 0; |
1049 |
jsr166 |
1.75 |
// checkInvariants(); |
1050 |
dl |
1.1 |
} |
1051 |
|
|
|
1052 |
|
|
/** |
1053 |
jsr166 |
1.106 |
* Nulls out slots starting at array index i, upto index end. |
1054 |
jsr166 |
1.89 |
*/ |
1055 |
jsr166 |
1.106 |
private static void circularClear(Object[] es, int i, int end) { |
1056 |
|
|
for (int to = (i <= end) ? end : es.length; |
1057 |
|
|
; i = 0, to = end) { |
1058 |
|
|
Arrays.fill(es, i, to, null); |
1059 |
|
|
if (to == end) break; |
1060 |
jsr166 |
1.99 |
} |
1061 |
jsr166 |
1.89 |
} |
1062 |
|
|
|
1063 |
|
|
/** |
1064 |
dl |
1.5 |
* Returns an array containing all of the elements in this deque |
1065 |
jsr166 |
1.10 |
* in proper sequence (from first to last element). |
1066 |
dl |
1.1 |
* |
1067 |
jsr166 |
1.10 |
* <p>The returned array will be "safe" in that no references to it are |
1068 |
|
|
* maintained by this deque. (In other words, this method must allocate |
1069 |
|
|
* a new array). The caller is thus free to modify the returned array. |
1070 |
jsr166 |
1.13 |
* |
1071 |
jsr166 |
1.11 |
* <p>This method acts as bridge between array-based and collection-based |
1072 |
|
|
* APIs. |
1073 |
|
|
* |
1074 |
dl |
1.5 |
* @return an array containing all of the elements in this deque |
1075 |
dl |
1.1 |
*/ |
1076 |
|
|
public Object[] toArray() { |
1077 |
jsr166 |
1.86 |
return toArray(Object[].class); |
1078 |
|
|
} |
1079 |
|
|
|
1080 |
|
|
private <T> T[] toArray(Class<T[]> klazz) { |
1081 |
jsr166 |
1.99 |
final Object[] es = elements; |
1082 |
jsr166 |
1.86 |
final T[] a; |
1083 |
jsr166 |
1.106 |
final int size = size(), head = this.head, end; |
1084 |
|
|
final int len = Math.min(size, es.length - head); |
1085 |
jsr166 |
1.102 |
if ((end = head + size) >= 0) { |
1086 |
jsr166 |
1.99 |
a = Arrays.copyOfRange(es, head, end, klazz); |
1087 |
jsr166 |
1.86 |
} else { |
1088 |
|
|
// integer overflow! |
1089 |
jsr166 |
1.99 |
a = Arrays.copyOfRange(es, 0, size, klazz); |
1090 |
jsr166 |
1.102 |
System.arraycopy(es, head, a, 0, len); |
1091 |
jsr166 |
1.86 |
} |
1092 |
jsr166 |
1.106 |
if (tail < head) |
1093 |
|
|
System.arraycopy(es, 0, a, len, tail); |
1094 |
jsr166 |
1.50 |
return a; |
1095 |
dl |
1.1 |
} |
1096 |
|
|
|
1097 |
|
|
/** |
1098 |
jsr166 |
1.10 |
* Returns an array containing all of the elements in this deque in |
1099 |
|
|
* proper sequence (from first to last element); the runtime type of the |
1100 |
|
|
* returned array is that of the specified array. If the deque fits in |
1101 |
|
|
* the specified array, it is returned therein. Otherwise, a new array |
1102 |
|
|
* is allocated with the runtime type of the specified array and the |
1103 |
|
|
* size of this deque. |
1104 |
|
|
* |
1105 |
|
|
* <p>If this deque fits in the specified array with room to spare |
1106 |
|
|
* (i.e., the array has more elements than this deque), the element in |
1107 |
|
|
* the array immediately following the end of the deque is set to |
1108 |
jsr166 |
1.40 |
* {@code null}. |
1109 |
jsr166 |
1.10 |
* |
1110 |
|
|
* <p>Like the {@link #toArray()} method, this method acts as bridge between |
1111 |
|
|
* array-based and collection-based APIs. Further, this method allows |
1112 |
|
|
* precise control over the runtime type of the output array, and may, |
1113 |
|
|
* under certain circumstances, be used to save allocation costs. |
1114 |
|
|
* |
1115 |
jsr166 |
1.40 |
* <p>Suppose {@code x} is a deque known to contain only strings. |
1116 |
jsr166 |
1.10 |
* The following code can be used to dump the deque into a newly |
1117 |
jsr166 |
1.40 |
* allocated array of {@code String}: |
1118 |
jsr166 |
1.10 |
* |
1119 |
jsr166 |
1.63 |
* <pre> {@code String[] y = x.toArray(new String[0]);}</pre> |
1120 |
jsr166 |
1.10 |
* |
1121 |
jsr166 |
1.40 |
* Note that {@code toArray(new Object[0])} is identical in function to |
1122 |
|
|
* {@code toArray()}. |
1123 |
dl |
1.1 |
* |
1124 |
|
|
* @param a the array into which the elements of the deque are to |
1125 |
jsr166 |
1.9 |
* be stored, if it is big enough; otherwise, a new array of the |
1126 |
|
|
* same runtime type is allocated for this purpose |
1127 |
jsr166 |
1.10 |
* @return an array containing all of the elements in this deque |
1128 |
|
|
* @throws ArrayStoreException if the runtime type of the specified array |
1129 |
|
|
* is not a supertype of the runtime type of every element in |
1130 |
|
|
* this deque |
1131 |
|
|
* @throws NullPointerException if the specified array is null |
1132 |
dl |
1.1 |
*/ |
1133 |
jsr166 |
1.34 |
@SuppressWarnings("unchecked") |
1134 |
dl |
1.1 |
public <T> T[] toArray(T[] a) { |
1135 |
jsr166 |
1.99 |
final int size; |
1136 |
jsr166 |
1.106 |
if ((size = size()) > a.length) |
1137 |
jsr166 |
1.86 |
return toArray((Class<T[]>) a.getClass()); |
1138 |
jsr166 |
1.99 |
final Object[] es = elements; |
1139 |
jsr166 |
1.106 |
for (int i = head, j = 0, len = Math.min(size, es.length - i); |
1140 |
|
|
; i = 0, len = tail) { |
1141 |
jsr166 |
1.101 |
System.arraycopy(es, i, a, j, len); |
1142 |
jsr166 |
1.106 |
if ((j += len) == size) break; |
1143 |
jsr166 |
1.101 |
} |
1144 |
jsr166 |
1.86 |
if (size < a.length) |
1145 |
|
|
a[size] = null; |
1146 |
dl |
1.1 |
return a; |
1147 |
|
|
} |
1148 |
|
|
|
1149 |
|
|
// *** Object methods *** |
1150 |
|
|
|
1151 |
|
|
/** |
1152 |
|
|
* Returns a copy of this deque. |
1153 |
|
|
* |
1154 |
|
|
* @return a copy of this deque |
1155 |
|
|
*/ |
1156 |
|
|
public ArrayDeque<E> clone() { |
1157 |
dl |
1.5 |
try { |
1158 |
jsr166 |
1.34 |
@SuppressWarnings("unchecked") |
1159 |
dl |
1.1 |
ArrayDeque<E> result = (ArrayDeque<E>) super.clone(); |
1160 |
jsr166 |
1.28 |
result.elements = Arrays.copyOf(elements, elements.length); |
1161 |
dl |
1.1 |
return result; |
1162 |
dl |
1.5 |
} catch (CloneNotSupportedException e) { |
1163 |
dl |
1.1 |
throw new AssertionError(); |
1164 |
|
|
} |
1165 |
|
|
} |
1166 |
|
|
|
1167 |
|
|
private static final long serialVersionUID = 2340985798034038923L; |
1168 |
|
|
|
1169 |
|
|
/** |
1170 |
jsr166 |
1.38 |
* Saves this deque to a stream (that is, serializes it). |
1171 |
dl |
1.1 |
* |
1172 |
jsr166 |
1.56 |
* @param s the stream |
1173 |
jsr166 |
1.57 |
* @throws java.io.IOException if an I/O error occurs |
1174 |
jsr166 |
1.40 |
* @serialData The current size ({@code int}) of the deque, |
1175 |
dl |
1.1 |
* followed by all of its elements (each an object reference) in |
1176 |
|
|
* first-to-last order. |
1177 |
|
|
*/ |
1178 |
jsr166 |
1.32 |
private void writeObject(java.io.ObjectOutputStream s) |
1179 |
|
|
throws java.io.IOException { |
1180 |
dl |
1.1 |
s.defaultWriteObject(); |
1181 |
|
|
|
1182 |
|
|
// Write out size |
1183 |
jsr166 |
1.106 |
s.writeInt(size()); |
1184 |
dl |
1.1 |
|
1185 |
|
|
// Write out elements in order. |
1186 |
jsr166 |
1.99 |
final Object[] es = elements; |
1187 |
jsr166 |
1.106 |
for (int i = head, end = tail, to = (i <= end) ? end : es.length; |
1188 |
|
|
; i = 0, to = end) { |
1189 |
jsr166 |
1.92 |
for (; i < to; i++) |
1190 |
jsr166 |
1.99 |
s.writeObject(es[i]); |
1191 |
jsr166 |
1.106 |
if (to == end) break; |
1192 |
jsr166 |
1.89 |
} |
1193 |
dl |
1.1 |
} |
1194 |
|
|
|
1195 |
|
|
/** |
1196 |
jsr166 |
1.38 |
* Reconstitutes this deque from a stream (that is, deserializes it). |
1197 |
jsr166 |
1.56 |
* @param s the stream |
1198 |
jsr166 |
1.57 |
* @throws ClassNotFoundException if the class of a serialized object |
1199 |
|
|
* could not be found |
1200 |
|
|
* @throws java.io.IOException if an I/O error occurs |
1201 |
dl |
1.1 |
*/ |
1202 |
jsr166 |
1.32 |
private void readObject(java.io.ObjectInputStream s) |
1203 |
|
|
throws java.io.IOException, ClassNotFoundException { |
1204 |
dl |
1.1 |
s.defaultReadObject(); |
1205 |
|
|
|
1206 |
|
|
// Read in size and allocate array |
1207 |
jsr166 |
1.106 |
int size = s.readInt(); |
1208 |
|
|
elements = new Object[size + 1]; |
1209 |
|
|
this.tail = size; |
1210 |
dl |
1.1 |
|
1211 |
|
|
// Read in all elements in the proper order. |
1212 |
|
|
for (int i = 0; i < size; i++) |
1213 |
jsr166 |
1.34 |
elements[i] = s.readObject(); |
1214 |
dl |
1.1 |
} |
1215 |
dl |
1.41 |
|
1216 |
jsr166 |
1.75 |
/** debugging */ |
1217 |
jsr166 |
1.89 |
void checkInvariants() { |
1218 |
jsr166 |
1.75 |
try { |
1219 |
|
|
int capacity = elements.length; |
1220 |
jsr166 |
1.106 |
// assert head >= 0 && head < capacity; |
1221 |
|
|
// assert tail >= 0 && tail < capacity; |
1222 |
|
|
// assert capacity > 0; |
1223 |
|
|
// assert size() < capacity; |
1224 |
|
|
// assert head == tail || elements[head] != null; |
1225 |
|
|
// assert elements[tail] == null; |
1226 |
|
|
// assert head == tail || elements[dec(tail, capacity)] != null; |
1227 |
jsr166 |
1.75 |
} catch (Throwable t) { |
1228 |
jsr166 |
1.106 |
System.err.printf("head=%d tail=%d capacity=%d%n", |
1229 |
|
|
head, tail, elements.length); |
1230 |
jsr166 |
1.75 |
System.err.printf("elements=%s%n", |
1231 |
|
|
Arrays.toString(elements)); |
1232 |
|
|
throw t; |
1233 |
dl |
1.41 |
} |
1234 |
|
|
} |
1235 |
|
|
|
1236 |
dl |
1.1 |
} |