| 27 |
|
* <p>The twelve methods described above are summarized in the |
| 28 |
|
* following table: |
| 29 |
|
* |
| 30 |
< |
* <p> |
| 31 |
< |
* <table BORDER CELLPADDING=3 CELLSPACING=1> |
| 30 |
> |
* <table class="striped"> |
| 31 |
> |
* <caption>Summary of Deque methods</caption> |
| 32 |
> |
* <thead> |
| 33 |
|
* <tr> |
| 34 |
< |
* <td></td> |
| 35 |
< |
* <td ALIGN=CENTER COLSPAN = 2> <b>First Element (Head)</b></td> |
| 36 |
< |
* <td ALIGN=CENTER COLSPAN = 2> <b>Last Element (Tail)</b></td> |
| 34 |
> |
* <td rowspan="2"></td> |
| 35 |
> |
* <th scope="col" colspan="2"> First Element (Head)</th> |
| 36 |
> |
* <th scope="col" colspan="2"> Last Element (Tail)</th> |
| 37 |
|
* </tr> |
| 38 |
|
* <tr> |
| 39 |
< |
* <td></td> |
| 40 |
< |
* <td ALIGN=CENTER><em>Throws exception</em></td> |
| 41 |
< |
* <td ALIGN=CENTER><em>Special value</em></td> |
| 42 |
< |
* <td ALIGN=CENTER><em>Throws exception</em></td> |
| 42 |
< |
* <td ALIGN=CENTER><em>Special value</em></td> |
| 39 |
> |
* <th scope="col" style="font-weight:normal; font-style:italic">Throws exception</th> |
| 40 |
> |
* <th scope="col" style="font-weight:normal; font-style:italic">Special value</th> |
| 41 |
> |
* <th scope="col" style="font-weight:normal; font-style:italic">Throws exception</th> |
| 42 |
> |
* <th scope="col" style="font-weight:normal; font-style:italic">Special value</th> |
| 43 |
|
* </tr> |
| 44 |
+ |
* </thead> |
| 45 |
+ |
* <tbody> |
| 46 |
|
* <tr> |
| 47 |
< |
* <td><b>Insert</b></td> |
| 48 |
< |
* <td>{@link #addFirst addFirst(e)}</td> |
| 49 |
< |
* <td>{@link #offerFirst offerFirst(e)}</td> |
| 50 |
< |
* <td>{@link #addLast addLast(e)}</td> |
| 51 |
< |
* <td>{@link #offerLast offerLast(e)}</td> |
| 47 |
> |
* <th scope="row">Insert</th> |
| 48 |
> |
* <td>{@link #addFirst(Object) addFirst(e)}</td> |
| 49 |
> |
* <td>{@link #offerFirst(Object) offerFirst(e)}</td> |
| 50 |
> |
* <td>{@link #addLast(Object) addLast(e)}</td> |
| 51 |
> |
* <td>{@link #offerLast(Object) offerLast(e)}</td> |
| 52 |
|
* </tr> |
| 53 |
|
* <tr> |
| 54 |
< |
* <td><b>Remove</b></td> |
| 55 |
< |
* <td>{@link #removeFirst removeFirst()}</td> |
| 56 |
< |
* <td>{@link #pollFirst pollFirst()}</td> |
| 57 |
< |
* <td>{@link #removeLast removeLast()}</td> |
| 58 |
< |
* <td>{@link #pollLast pollLast()}</td> |
| 54 |
> |
* <th scope="row">Remove</th> |
| 55 |
> |
* <td>{@link #removeFirst() removeFirst()}</td> |
| 56 |
> |
* <td>{@link #pollFirst() pollFirst()}</td> |
| 57 |
> |
* <td>{@link #removeLast() removeLast()}</td> |
| 58 |
> |
* <td>{@link #pollLast() pollLast()}</td> |
| 59 |
|
* </tr> |
| 60 |
|
* <tr> |
| 61 |
< |
* <td><b>Examine</b></td> |
| 62 |
< |
* <td>{@link #getFirst getFirst()}</td> |
| 63 |
< |
* <td>{@link #peekFirst peekFirst()}</td> |
| 64 |
< |
* <td>{@link #getLast getLast()}</td> |
| 65 |
< |
* <td>{@link #peekLast peekLast()}</td> |
| 61 |
> |
* <th scope="row">Examine</th> |
| 62 |
> |
* <td>{@link #getFirst() getFirst()}</td> |
| 63 |
> |
* <td>{@link #peekFirst() peekFirst()}</td> |
| 64 |
> |
* <td>{@link #getLast() getLast()}</td> |
| 65 |
> |
* <td>{@link #peekLast() peekLast()}</td> |
| 66 |
|
* </tr> |
| 67 |
+ |
* </tbody> |
| 68 |
|
* </table> |
| 69 |
|
* |
| 70 |
|
* <p>This interface extends the {@link Queue} interface. When a deque is |
| 73 |
|
* inherited from the {@code Queue} interface are precisely equivalent to |
| 74 |
|
* {@code Deque} methods as indicated in the following table: |
| 75 |
|
* |
| 76 |
< |
* <p> |
| 77 |
< |
* <table BORDER CELLPADDING=3 CELLSPACING=1> |
| 76 |
> |
* <table class="striped"> |
| 77 |
> |
* <caption>Comparison of Queue and Deque methods</caption> |
| 78 |
> |
* <thead> |
| 79 |
|
* <tr> |
| 80 |
< |
* <td ALIGN=CENTER> <b>{@code Queue} Method</b></td> |
| 81 |
< |
* <td ALIGN=CENTER> <b>Equivalent {@code Deque} Method</b></td> |
| 80 |
> |
* <th scope="col"> {@code Queue} Method</th> |
| 81 |
> |
* <th scope="col"> Equivalent {@code Deque} Method</th> |
| 82 |
|
* </tr> |
| 83 |
+ |
* </thead> |
| 84 |
+ |
* <tbody> |
| 85 |
|
* <tr> |
| 86 |
< |
* <td>{@link java.util.Queue#add add(e)}</td> |
| 87 |
< |
* <td>{@link #addLast addLast(e)}</td> |
| 86 |
> |
* <th scope="row">{@link #add(Object) add(e)}</th> |
| 87 |
> |
* <td>{@link #addLast(Object) addLast(e)}</td> |
| 88 |
|
* </tr> |
| 89 |
|
* <tr> |
| 90 |
< |
* <td>{@link java.util.Queue#offer offer(e)}</td> |
| 91 |
< |
* <td>{@link #offerLast offerLast(e)}</td> |
| 90 |
> |
* <th scope="row">{@link #offer(Object) offer(e)}</th> |
| 91 |
> |
* <td>{@link #offerLast(Object) offerLast(e)}</td> |
| 92 |
|
* </tr> |
| 93 |
|
* <tr> |
| 94 |
< |
* <td>{@link java.util.Queue#remove remove()}</td> |
| 95 |
< |
* <td>{@link #removeFirst removeFirst()}</td> |
| 94 |
> |
* <th scope="row">{@link #remove() remove()}</th> |
| 95 |
> |
* <td>{@link #removeFirst() removeFirst()}</td> |
| 96 |
|
* </tr> |
| 97 |
|
* <tr> |
| 98 |
< |
* <td>{@link java.util.Queue#poll poll()}</td> |
| 99 |
< |
* <td>{@link #pollFirst pollFirst()}</td> |
| 98 |
> |
* <th scope="row">{@link #poll() poll()}</th> |
| 99 |
> |
* <td>{@link #pollFirst() pollFirst()}</td> |
| 100 |
|
* </tr> |
| 101 |
|
* <tr> |
| 102 |
< |
* <td>{@link java.util.Queue#element element()}</td> |
| 103 |
< |
* <td>{@link #getFirst getFirst()}</td> |
| 102 |
> |
* <th scope="row">{@link #element() element()}</th> |
| 103 |
> |
* <td>{@link #getFirst() getFirst()}</td> |
| 104 |
|
* </tr> |
| 105 |
|
* <tr> |
| 106 |
< |
* <td>{@link java.util.Queue#peek peek()}</td> |
| 107 |
< |
* <td>{@link #peek peekFirst()}</td> |
| 106 |
> |
* <th scope="row">{@link #peek() peek()}</th> |
| 107 |
> |
* <td>{@link #peekFirst() peekFirst()}</td> |
| 108 |
|
* </tr> |
| 109 |
+ |
* </tbody> |
| 110 |
|
* </table> |
| 111 |
|
* |
| 112 |
|
* <p>Deques can also be used as LIFO (Last-In-First-Out) stacks. This |
| 113 |
|
* interface should be used in preference to the legacy {@link Stack} class. |
| 114 |
|
* When a deque is used as a stack, elements are pushed and popped from the |
| 115 |
< |
* beginning of the deque. Stack methods are precisely equivalent to |
| 116 |
< |
* {@code Deque} methods as indicated in the table below: |
| 115 |
> |
* beginning of the deque. Stack methods are equivalent to {@code Deque} |
| 116 |
> |
* methods as indicated in the table below: |
| 117 |
|
* |
| 118 |
< |
* <p> |
| 119 |
< |
* <table BORDER CELLPADDING=3 CELLSPACING=1> |
| 118 |
> |
* <table class="striped"> |
| 119 |
> |
* <caption>Comparison of Stack and Deque methods</caption> |
| 120 |
> |
* <thead> |
| 121 |
|
* <tr> |
| 122 |
< |
* <td ALIGN=CENTER> <b>Stack Method</b></td> |
| 123 |
< |
* <td ALIGN=CENTER> <b>Equivalent {@code Deque} Method</b></td> |
| 122 |
> |
* <th scope="col"> Stack Method</th> |
| 123 |
> |
* <th scope="col"> Equivalent {@code Deque} Method</th> |
| 124 |
|
* </tr> |
| 125 |
+ |
* </thead> |
| 126 |
+ |
* <tbody> |
| 127 |
|
* <tr> |
| 128 |
< |
* <td>{@link #push push(e)}</td> |
| 129 |
< |
* <td>{@link #addFirst addFirst(e)}</td> |
| 128 |
> |
* <th scope="row">{@link #push(Object) push(e)}</th> |
| 129 |
> |
* <td>{@link #addFirst(Object) addFirst(e)}</td> |
| 130 |
|
* </tr> |
| 131 |
|
* <tr> |
| 132 |
< |
* <td>{@link #pop pop()}</td> |
| 133 |
< |
* <td>{@link #removeFirst removeFirst()}</td> |
| 132 |
> |
* <th scope="row">{@link #pop() pop()}</th> |
| 133 |
> |
* <td>{@link #removeFirst() removeFirst()}</td> |
| 134 |
|
* </tr> |
| 135 |
|
* <tr> |
| 136 |
< |
* <td>{@link #peek peek()}</td> |
| 137 |
< |
* <td>{@link #peekFirst peekFirst()}</td> |
| 136 |
> |
* <th scope="row">{@link #peek() peek()}</th> |
| 137 |
> |
* <td>{@link #getFirst() getFirst()}</td> |
| 138 |
|
* </tr> |
| 139 |
+ |
* </tbody> |
| 140 |
|
* </table> |
| 141 |
|
* |
| 142 |
|
* <p>Note that the {@link #peek peek} method works equally well when |
| 156 |
|
* that do allow null elements are strongly encouraged <i>not</i> to |
| 157 |
|
* take advantage of the ability to insert nulls. This is so because |
| 158 |
|
* {@code null} is used as a special return value by various methods |
| 159 |
< |
* to indicated that the deque is empty. |
| 159 |
> |
* to indicate that the deque is empty. |
| 160 |
|
* |
| 161 |
|
* <p>{@code Deque} implementations generally do not define |
| 162 |
|
* element-based versions of the {@code equals} and {@code hashCode} |
| 163 |
|
* methods, but instead inherit the identity-based versions from class |
| 164 |
|
* {@code Object}. |
| 165 |
|
* |
| 166 |
< |
* <p>This interface is a member of the <a |
| 167 |
< |
* href="{@docRoot}/../technotes/guides/collections/index.html"> Java Collections |
| 168 |
< |
* Framework</a>. |
| 166 |
> |
* <p>This interface is a member of the |
| 167 |
> |
* <a href="{@docRoot}/java/util/package-summary.html#CollectionsFramework"> |
| 168 |
> |
* Java Collections Framework</a>. |
| 169 |
|
* |
| 170 |
|
* @author Doug Lea |
| 171 |
|
* @author Josh Bloch |
| 172 |
|
* @since 1.6 |
| 173 |
< |
* @param <E> the type of elements held in this collection |
| 173 |
> |
* @param <E> the type of elements held in this deque |
| 174 |
|
*/ |
| 175 |
|
public interface Deque<E> extends Queue<E> { |
| 176 |
|
/** |
| 177 |
|
* Inserts the specified element at the front of this deque if it is |
| 178 |
< |
* possible to do so immediately without violating capacity restrictions. |
| 179 |
< |
* When using a capacity-restricted deque, it is generally preferable to |
| 180 |
< |
* use method {@link #offerFirst}. |
| 178 |
> |
* possible to do so immediately without violating capacity restrictions, |
| 179 |
> |
* throwing an {@code IllegalStateException} if no space is currently |
| 180 |
> |
* available. When using a capacity-restricted deque, it is generally |
| 181 |
> |
* preferable to use method {@link #offerFirst}. |
| 182 |
|
* |
| 183 |
|
* @param e the element to add |
| 184 |
|
* @throws IllegalStateException if the element cannot be added at this |
| 194 |
|
|
| 195 |
|
/** |
| 196 |
|
* Inserts the specified element at the end of this deque if it is |
| 197 |
< |
* possible to do so immediately without violating capacity restrictions. |
| 198 |
< |
* When using a capacity-restricted deque, it is generally preferable to |
| 199 |
< |
* use method {@link #offerLast}. |
| 197 |
> |
* possible to do so immediately without violating capacity restrictions, |
| 198 |
> |
* throwing an {@code IllegalStateException} if no space is currently |
| 199 |
> |
* available. When using a capacity-restricted deque, it is generally |
| 200 |
> |
* preferable to use method {@link #offerLast}. |
| 201 |
|
* |
| 202 |
|
* <p>This method is equivalent to {@link #add}. |
| 203 |
|
* |
| 326 |
|
* Removes the first occurrence of the specified element from this deque. |
| 327 |
|
* If the deque does not contain the element, it is unchanged. |
| 328 |
|
* More formally, removes the first element {@code e} such that |
| 329 |
< |
* <tt>(o==null ? e==null : o.equals(e))</tt> |
| 317 |
< |
* (if such an element exists). |
| 329 |
> |
* {@code Objects.equals(o, e)} (if such an element exists). |
| 330 |
|
* Returns {@code true} if this deque contained the specified element |
| 331 |
|
* (or equivalently, if this deque changed as a result of the call). |
| 332 |
|
* |
| 333 |
|
* @param o element to be removed from this deque, if present |
| 334 |
|
* @return {@code true} if an element was removed as a result of this call |
| 335 |
|
* @throws ClassCastException if the class of the specified element |
| 336 |
< |
* is incompatible with this deque (optional) |
| 336 |
> |
* is incompatible with this deque |
| 337 |
> |
* (<a href="{@docRoot}/../api/java/util/Collection.html#optional-restrictions">optional</a>) |
| 338 |
|
* @throws NullPointerException if the specified element is null and this |
| 339 |
< |
* deque does not permit null elements (optional) |
| 339 |
> |
* deque does not permit null elements |
| 340 |
> |
* (<a href="{@docRoot}/../api/java/util/Collection.html#optional-restrictions">optional</a>) |
| 341 |
|
*/ |
| 342 |
|
boolean removeFirstOccurrence(Object o); |
| 343 |
|
|
| 345 |
|
* Removes the last occurrence of the specified element from this deque. |
| 346 |
|
* If the deque does not contain the element, it is unchanged. |
| 347 |
|
* More formally, removes the last element {@code e} such that |
| 348 |
< |
* <tt>(o==null ? e==null : o.equals(e))</tt> |
| 335 |
< |
* (if such an element exists). |
| 348 |
> |
* {@code Objects.equals(o, e)} (if such an element exists). |
| 349 |
|
* Returns {@code true} if this deque contained the specified element |
| 350 |
|
* (or equivalently, if this deque changed as a result of the call). |
| 351 |
|
* |
| 352 |
|
* @param o element to be removed from this deque, if present |
| 353 |
|
* @return {@code true} if an element was removed as a result of this call |
| 354 |
|
* @throws ClassCastException if the class of the specified element |
| 355 |
< |
* is incompatible with this deque (optional) |
| 355 |
> |
* is incompatible with this deque |
| 356 |
> |
* (<a href="{@docRoot}/../api/java/util/Collection.html#optional-restrictions">optional</a>) |
| 357 |
|
* @throws NullPointerException if the specified element is null and this |
| 358 |
< |
* deque does not permit null elements (optional) |
| 358 |
> |
* deque does not permit null elements |
| 359 |
> |
* (<a href="{@docRoot}/../api/java/util/Collection.html#optional-restrictions">optional</a>) |
| 360 |
|
*/ |
| 361 |
|
boolean removeLastOccurrence(Object o); |
| 362 |
|
|
| 412 |
|
/** |
| 413 |
|
* Retrieves and removes the head of the queue represented by this deque |
| 414 |
|
* (in other words, the first element of this deque). |
| 415 |
< |
* This method differs from {@link #poll poll} only in that it throws an |
| 416 |
< |
* exception if this deque is empty. |
| 415 |
> |
* This method differs from {@link #poll() poll()} only in that it |
| 416 |
> |
* throws an exception if this deque is empty. |
| 417 |
|
* |
| 418 |
|
* <p>This method is equivalent to {@link #removeFirst()}. |
| 419 |
|
* |
| 459 |
|
*/ |
| 460 |
|
E peek(); |
| 461 |
|
|
| 462 |
+ |
/** |
| 463 |
+ |
* Adds all of the elements in the specified collection at the end |
| 464 |
+ |
* of this deque, as if by calling {@link #addLast} on each one, |
| 465 |
+ |
* in the order that they are returned by the collection's iterator. |
| 466 |
+ |
* |
| 467 |
+ |
* <p>When using a capacity-restricted deque, it is generally preferable |
| 468 |
+ |
* to call {@link #offer(Object) offer} separately on each element. |
| 469 |
+ |
* |
| 470 |
+ |
* <p>An exception encountered while trying to add an element may result |
| 471 |
+ |
* in only some of the elements having been successfully added when |
| 472 |
+ |
* the associated exception is thrown. |
| 473 |
+ |
* |
| 474 |
+ |
* @param c the elements to be inserted into this deque |
| 475 |
+ |
* @return {@code true} if this deque changed as a result of the call |
| 476 |
+ |
* @throws IllegalStateException if not all the elements can be added at |
| 477 |
+ |
* this time due to insertion restrictions |
| 478 |
+ |
* @throws ClassCastException if the class of an element of the specified |
| 479 |
+ |
* collection prevents it from being added to this deque |
| 480 |
+ |
* @throws NullPointerException if the specified collection contains a |
| 481 |
+ |
* null element and this deque does not permit null elements, |
| 482 |
+ |
* or if the specified collection is null |
| 483 |
+ |
* @throws IllegalArgumentException if some property of an element of the |
| 484 |
+ |
* specified collection prevents it from being added to this deque |
| 485 |
+ |
*/ |
| 486 |
+ |
boolean addAll(Collection<? extends E> c); |
| 487 |
|
|
| 488 |
|
// *** Stack methods *** |
| 489 |
|
|
| 490 |
|
/** |
| 491 |
|
* Pushes an element onto the stack represented by this deque (in other |
| 492 |
|
* words, at the head of this deque) if it is possible to do so |
| 493 |
< |
* immediately without violating capacity restrictions, returning |
| 454 |
< |
* {@code true} upon success and throwing an |
| 493 |
> |
* immediately without violating capacity restrictions, throwing an |
| 494 |
|
* {@code IllegalStateException} if no space is currently available. |
| 495 |
|
* |
| 496 |
|
* <p>This method is equivalent to {@link #addFirst}. |
| 526 |
|
* Removes the first occurrence of the specified element from this deque. |
| 527 |
|
* If the deque does not contain the element, it is unchanged. |
| 528 |
|
* More formally, removes the first element {@code e} such that |
| 529 |
< |
* <tt>(o==null ? e==null : o.equals(e))</tt> |
| 491 |
< |
* (if such an element exists). |
| 529 |
> |
* {@code Objects.equals(o, e)} (if such an element exists). |
| 530 |
|
* Returns {@code true} if this deque contained the specified element |
| 531 |
|
* (or equivalently, if this deque changed as a result of the call). |
| 532 |
|
* |
| 535 |
|
* @param o element to be removed from this deque, if present |
| 536 |
|
* @return {@code true} if an element was removed as a result of this call |
| 537 |
|
* @throws ClassCastException if the class of the specified element |
| 538 |
< |
* is incompatible with this deque (optional) |
| 538 |
> |
* is incompatible with this deque |
| 539 |
> |
* (<a href="{@docRoot}/../api/java/util/Collection.html#optional-restrictions">optional</a>) |
| 540 |
|
* @throws NullPointerException if the specified element is null and this |
| 541 |
< |
* deque does not permit null elements (optional) |
| 541 |
> |
* deque does not permit null elements |
| 542 |
> |
* (<a href="{@docRoot}/../api/java/util/Collection.html#optional-restrictions">optional</a>) |
| 543 |
|
*/ |
| 544 |
|
boolean remove(Object o); |
| 545 |
|
|
| 546 |
|
/** |
| 547 |
|
* Returns {@code true} if this deque contains the specified element. |
| 548 |
|
* More formally, returns {@code true} if and only if this deque contains |
| 549 |
< |
* at least one element {@code e} such that |
| 510 |
< |
* <tt>(o==null ? e==null : o.equals(e))</tt>. |
| 549 |
> |
* at least one element {@code e} such that {@code Objects.equals(o, e)}. |
| 550 |
|
* |
| 551 |
|
* @param o element whose presence in this deque is to be tested |
| 552 |
|
* @return {@code true} if this deque contains the specified element |
| 553 |
< |
* @throws ClassCastException if the type of the specified element |
| 554 |
< |
* is incompatible with this deque (optional) |
| 553 |
> |
* @throws ClassCastException if the class of the specified element |
| 554 |
> |
* is incompatible with this deque |
| 555 |
> |
* (<a href="{@docRoot}/../api/java/util/Collection.html#optional-restrictions">optional</a>) |
| 556 |
|
* @throws NullPointerException if the specified element is null and this |
| 557 |
< |
* deque does not permit null elements (optional) |
| 557 |
> |
* deque does not permit null elements |
| 558 |
> |
* (<a href="{@docRoot}/../api/java/util/Collection.html#optional-restrictions">optional</a>) |
| 559 |
|
*/ |
| 560 |
|
boolean contains(Object o); |
| 561 |
|
|
| 564 |
|
* |
| 565 |
|
* @return the number of elements in this deque |
| 566 |
|
*/ |
| 567 |
< |
public int size(); |
| 567 |
> |
int size(); |
| 568 |
|
|
| 569 |
|
/** |
| 570 |
|
* Returns an iterator over the elements in this deque in proper sequence. |
