| 1 |
|
/* |
| 2 |
|
* %W% %E% |
| 3 |
|
* |
| 4 |
< |
* Copyright 2003 Sun Microsystems, Inc. All rights reserved. |
| 4 |
> |
* Copyright 2005 Sun Microsystems, Inc. All rights reserved. |
| 5 |
|
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. |
| 6 |
|
*/ |
| 7 |
|
|
| 14 |
|
* the <tt>LinkedList</tt> class provides uniformly named methods to |
| 15 |
|
* <tt>get</tt>, <tt>remove</tt> and <tt>insert</tt> an element at the |
| 16 |
|
* beginning and end of the list. These operations allow linked lists to be |
| 17 |
< |
* used as a stack, queue, or double-ended queue (deque).<p> |
| 17 |
> |
* used as a stack, {@linkplain Queue queue}, or {@linkplain Deque |
| 18 |
> |
* double-ended queue}. <p> |
| 19 |
|
* |
| 20 |
< |
* The class implements the <tt>Queue</tt> interface, providing |
| 20 |
> |
* The class implements the <tt>Deque</tt> interface, providing |
| 21 |
|
* first-in-first-out queue operations for <tt>add</tt>, |
| 22 |
< |
* <tt>poll</tt>, etc. Other stack and deque operations could be |
| 22 |
< |
* easily recast in terms of the standard list operations. They're |
| 23 |
< |
* included here primarily for convenience, though they may run |
| 24 |
< |
* slightly faster than the equivalent List operations.<p> |
| 22 |
> |
* <tt>poll</tt>, along with other stack and deque operations.<p> |
| 23 |
|
* |
| 24 |
|
* All of the operations perform as could be expected for a doubly-linked |
| 25 |
|
* list. Operations that index into the list will traverse the list from |
| 36 |
|
* Collections.synchronizedList method. This is best done at creation time, |
| 37 |
|
* to prevent accidental unsynchronized access to the list: <pre> |
| 38 |
|
* List list = Collections.synchronizedList(new LinkedList(...)); |
| 39 |
< |
* </pre><p> |
| 39 |
> |
* </pre> |
| 40 |
|
* |
| 41 |
< |
* The iterators returned by the this class's <tt>iterator</tt> and |
| 41 |
> |
* <p>The iterators returned by this class's <tt>iterator</tt> and |
| 42 |
|
* <tt>listIterator</tt> methods are <i>fail-fast</i>: if the list is |
| 43 |
< |
* structurally modified at any time after the iterator is created, in any way |
| 44 |
< |
* except through the Iterator's own <tt>remove</tt> or <tt>add</tt> methods, |
| 45 |
< |
* the iterator will throw a <tt>ConcurrentModificationException</tt>. Thus, |
| 46 |
< |
* in the face of concurrent modification, the iterator fails quickly and |
| 47 |
< |
* cleanly, rather than risking arbitrary, non-deterministic behavior at an |
| 48 |
< |
* undetermined time in the future. |
| 43 |
> |
* structurally modified at any time after the iterator is created, in |
| 44 |
> |
* any way except through the Iterator's own <tt>remove</tt> or |
| 45 |
> |
* <tt>add</tt> methods, the iterator will throw a {@link |
| 46 |
> |
* ConcurrentModificationException}. Thus, in the face of concurrent |
| 47 |
> |
* modification, the iterator fails quickly and cleanly, rather than |
| 48 |
> |
* risking arbitrary, non-deterministic behavior at an undetermined |
| 49 |
> |
* time in the future. |
| 50 |
|
* |
| 51 |
|
* <p>Note that the fail-fast behavior of an iterator cannot be guaranteed |
| 52 |
|
* as it is, generally speaking, impossible to make any hard guarantees in the |
| 54 |
|
* throw <tt>ConcurrentModificationException</tt> on a best-effort basis. |
| 55 |
|
* Therefore, it would be wrong to write a program that depended on this |
| 56 |
|
* exception for its correctness: <i>the fail-fast behavior of iterators |
| 57 |
< |
* should be used only to detect bugs.</i><p> |
| 57 |
> |
* should be used only to detect bugs.</i> |
| 58 |
|
* |
| 59 |
< |
* This class is a member of the |
| 59 |
> |
* <p>This class is a member of the |
| 60 |
|
* <a href="{@docRoot}/../guide/collections/index.html"> |
| 61 |
|
* Java Collections Framework</a>. |
| 62 |
|
* |
| 63 |
|
* @author Josh Bloch |
| 64 |
|
* @version %I%, %G% |
| 65 |
< |
* @see List |
| 66 |
< |
* @see ArrayList |
| 67 |
< |
* @see Vector |
| 68 |
< |
* @see Collections#synchronizedList(List) |
| 65 |
> |
* @see List |
| 66 |
> |
* @see ArrayList |
| 67 |
> |
* @see Vector |
| 68 |
> |
* @see Collections#synchronizedList(List) |
| 69 |
|
* @since 1.2 |
| 70 |
|
* @param <E> the type of elements held in this collection |
| 71 |
|
*/ |
| 72 |
|
|
| 73 |
|
public class LinkedList<E> |
| 74 |
|
extends AbstractSequentialList<E> |
| 75 |
< |
implements List<E>, Queue<E>, Cloneable, java.io.Serializable |
| 75 |
> |
implements List<E>, Deque<E>, Cloneable, java.io.Serializable |
| 76 |
|
{ |
| 77 |
|
private transient Entry<E> header = new Entry<E>(null, null, null); |
| 78 |
|
private transient int size = 0; |
| 89 |
|
* collection, in the order they are returned by the collection's |
| 90 |
|
* iterator. |
| 91 |
|
* |
| 92 |
< |
* @param c the collection whose elements are to be placed into this list. |
| 93 |
< |
* @throws NullPointerException if the specified collection is null. |
| 92 |
> |
* @param c the collection whose elements are to be placed into this list |
| 93 |
> |
* @throws NullPointerException if the specified collection is null |
| 94 |
|
*/ |
| 95 |
< |
public LinkedList(Collection<? extends E> c) { |
| 96 |
< |
this(); |
| 97 |
< |
addAll(c); |
| 98 |
< |
} |
| 95 |
> |
public LinkedList(Collection<? extends E> c) { |
| 96 |
> |
this(); |
| 97 |
> |
addAll(c); |
| 98 |
> |
} |
| 99 |
|
|
| 100 |
|
/** |
| 101 |
|
* Returns the first element in this list. |
| 102 |
|
* |
| 103 |
< |
* @return the first element in this list. |
| 104 |
< |
* @throws NoSuchElementException if this list is empty. |
| 103 |
> |
* @return the first element in this list |
| 104 |
> |
* @throws NoSuchElementException if this list is empty |
| 105 |
|
*/ |
| 106 |
|
public E getFirst() { |
| 107 |
< |
if (size==0) |
| 108 |
< |
throw new NoSuchElementException(); |
| 107 |
> |
if (size==0) |
| 108 |
> |
throw new NoSuchElementException(); |
| 109 |
|
|
| 110 |
< |
return header.next.element; |
| 110 |
> |
return header.next.element; |
| 111 |
|
} |
| 112 |
|
|
| 113 |
|
/** |
| 114 |
|
* Returns the last element in this list. |
| 115 |
|
* |
| 116 |
< |
* @return the last element in this list. |
| 117 |
< |
* @throws NoSuchElementException if this list is empty. |
| 116 |
> |
* @return the last element in this list |
| 117 |
> |
* @throws NoSuchElementException if this list is empty |
| 118 |
|
*/ |
| 119 |
|
public E getLast() { |
| 120 |
< |
if (size==0) |
| 121 |
< |
throw new NoSuchElementException(); |
| 120 |
> |
if (size==0) |
| 121 |
> |
throw new NoSuchElementException(); |
| 122 |
|
|
| 123 |
< |
return header.previous.element; |
| 123 |
> |
return header.previous.element; |
| 124 |
|
} |
| 125 |
|
|
| 126 |
|
/** |
| 127 |
|
* Removes and returns the first element from this list. |
| 128 |
|
* |
| 129 |
< |
* @return the first element from this list. |
| 130 |
< |
* @throws NoSuchElementException if this list is empty. |
| 129 |
> |
* @return the first element from this list |
| 130 |
> |
* @throws NoSuchElementException if this list is empty |
| 131 |
|
*/ |
| 132 |
|
public E removeFirst() { |
| 133 |
< |
E first = header.next.element; |
| 135 |
< |
remove(header.next); |
| 136 |
< |
return first; |
| 133 |
> |
return remove(header.next); |
| 134 |
|
} |
| 135 |
|
|
| 136 |
|
/** |
| 137 |
|
* Removes and returns the last element from this list. |
| 138 |
|
* |
| 139 |
< |
* @return the last element from this list. |
| 140 |
< |
* @throws NoSuchElementException if this list is empty. |
| 139 |
> |
* @return the last element from this list |
| 140 |
> |
* @throws NoSuchElementException if this list is empty |
| 141 |
|
*/ |
| 142 |
|
public E removeLast() { |
| 143 |
< |
E last = header.previous.element; |
| 147 |
< |
remove(header.previous); |
| 148 |
< |
return last; |
| 143 |
> |
return remove(header.previous); |
| 144 |
|
} |
| 145 |
|
|
| 146 |
|
/** |
| 147 |
|
* Inserts the given element at the beginning of this list. |
| 148 |
|
* |
| 149 |
< |
* @param o the element to be inserted at the beginning of this list. |
| 149 |
> |
* @param e the element to be inserted at the beginning of this list |
| 150 |
|
*/ |
| 151 |
< |
public void addFirst(E o) { |
| 152 |
< |
addBefore(o, header.next); |
| 151 |
> |
public void addFirst(E e) { |
| 152 |
> |
addBefore(e, header.next); |
| 153 |
|
} |
| 154 |
|
|
| 155 |
|
/** |
| 156 |
|
* Appends the given element to the end of this list. (Identical in |
| 157 |
|
* function to the <tt>add</tt> method; included only for consistency.) |
| 158 |
|
* |
| 159 |
< |
* @param o the element to be inserted at the end of this list. |
| 159 |
> |
* @param e the element to be inserted at the end of this list |
| 160 |
|
*/ |
| 161 |
< |
public void addLast(E o) { |
| 162 |
< |
addBefore(o, header); |
| 161 |
> |
public void addLast(E e) { |
| 162 |
> |
addBefore(e, header); |
| 163 |
|
} |
| 164 |
|
|
| 165 |
|
/** |
| 168 |
|
* at least one element <tt>e</tt> such that <tt>(o==null ? e==null |
| 169 |
|
* : o.equals(e))</tt>. |
| 170 |
|
* |
| 171 |
< |
* @param o element whose presence in this list is to be tested. |
| 172 |
< |
* @return <tt>true</tt> if this list contains the specified element. |
| 171 |
> |
* @param o element whose presence in this list is to be tested |
| 172 |
> |
* @return <tt>true</tt> if this list contains the specified element |
| 173 |
|
*/ |
| 174 |
|
public boolean contains(Object o) { |
| 175 |
|
return indexOf(o) != -1; |
| 178 |
|
/** |
| 179 |
|
* Returns the number of elements in this list. |
| 180 |
|
* |
| 181 |
< |
* @return the number of elements in this list. |
| 181 |
> |
* @return the number of elements in this list |
| 182 |
|
*/ |
| 183 |
|
public int size() { |
| 184 |
< |
return size; |
| 184 |
> |
return size; |
| 185 |
|
} |
| 186 |
|
|
| 187 |
|
/** |
| 188 |
|
* Appends the specified element to the end of this list. |
| 189 |
|
* |
| 190 |
< |
* @param o element to be appended to this list. |
| 191 |
< |
* @return <tt>true</tt> (as per the general contract of |
| 197 |
< |
* <tt>Collection.add</tt>). |
| 190 |
> |
* @param e element to be appended to this list |
| 191 |
> |
* @return <tt>true</tt> (as per the spec for {@link Collection#add}) |
| 192 |
|
*/ |
| 193 |
< |
public boolean add(E o) { |
| 194 |
< |
addBefore(o, header); |
| 193 |
> |
public boolean add(E e) { |
| 194 |
> |
addBefore(e, header); |
| 195 |
|
return true; |
| 196 |
|
} |
| 197 |
|
|
| 202 |
|
* <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt> (if such an |
| 203 |
|
* element exists). |
| 204 |
|
* |
| 205 |
< |
* @param o element to be removed from this list, if present. |
| 206 |
< |
* @return <tt>true</tt> if the list contained the specified element. |
| 205 |
> |
* @param o element to be removed from this list, if present |
| 206 |
> |
* @return <tt>true</tt> if the list contained the specified element |
| 207 |
|
*/ |
| 208 |
|
public boolean remove(Object o) { |
| 209 |
|
if (o==null) { |
| 232 |
|
* progress. (This implies that the behavior of this call is undefined if |
| 233 |
|
* the specified Collection is this list, and this list is nonempty.) |
| 234 |
|
* |
| 235 |
< |
* @param c the elements to be inserted into this list. |
| 236 |
< |
* @return <tt>true</tt> if this list changed as a result of the call. |
| 237 |
< |
* @throws NullPointerException if the specified collection is null. |
| 235 |
> |
* @param c the elements to be inserted into this list |
| 236 |
> |
* @return <tt>true</tt> if this list changed as a result of the call |
| 237 |
> |
* @throws NullPointerException if the specified collection is null |
| 238 |
|
*/ |
| 239 |
|
public boolean addAll(Collection<? extends E> c) { |
| 240 |
|
return addAll(size, c); |
| 248 |
|
* in the list in the order that they are returned by the |
| 249 |
|
* specified collection's iterator. |
| 250 |
|
* |
| 251 |
< |
* @param index index at which to insert first element |
| 252 |
< |
* from the specified collection. |
| 253 |
< |
* @param c elements to be inserted into this list. |
| 254 |
< |
* @return <tt>true</tt> if this list changed as a result of the call. |
| 255 |
< |
* @throws IndexOutOfBoundsException if the specified index is out of |
| 256 |
< |
* range (<tt>index < 0 || index > size()</tt>). |
| 257 |
< |
* @throws NullPointerException if the specified collection is null. |
| 251 |
> |
* @param index index at which to insert the first element |
| 252 |
> |
* from the specified collection |
| 253 |
> |
* @param c elements to be inserted into this list |
| 254 |
> |
* @return <tt>true</tt> if this list changed as a result of the call |
| 255 |
> |
* @throws IndexOutOfBoundsException if the index is out of range |
| 256 |
> |
* (<tt>index < 0 || index > size()</tt>) |
| 257 |
> |
* @throws NullPointerException if the specified collection is null |
| 258 |
|
*/ |
| 259 |
|
public boolean addAll(int index, Collection<? extends E> c) { |
| 260 |
|
if (index < 0 || index > size) |
| 264 |
|
int numNew = a.length; |
| 265 |
|
if (numNew==0) |
| 266 |
|
return false; |
| 267 |
< |
modCount++; |
| 267 |
> |
modCount++; |
| 268 |
|
|
| 269 |
|
Entry<E> successor = (index==size ? header : entry(index)); |
| 270 |
|
Entry<E> predecessor = successor.previous; |
| 271 |
< |
for (int i=0; i<numNew; i++) { |
| 271 |
> |
for (int i=0; i<numNew; i++) { |
| 272 |
|
Entry<E> e = new Entry<E>((E)a[i], successor, predecessor); |
| 273 |
|
predecessor.next = e; |
| 274 |
|
predecessor = e; |
| 283 |
|
* Removes all of the elements from this list. |
| 284 |
|
*/ |
| 285 |
|
public void clear() { |
| 286 |
< |
modCount++; |
| 286 |
> |
Entry<E> e = header.next; |
| 287 |
> |
while (e != header) { |
| 288 |
> |
Entry<E> next = e.next; |
| 289 |
> |
e.next = e.previous = null; |
| 290 |
> |
e.element = null; |
| 291 |
> |
e = next; |
| 292 |
> |
} |
| 293 |
|
header.next = header.previous = header; |
| 294 |
|
size = 0; |
| 295 |
+ |
modCount++; |
| 296 |
|
} |
| 297 |
|
|
| 298 |
|
|
| 301 |
|
/** |
| 302 |
|
* Returns the element at the specified position in this list. |
| 303 |
|
* |
| 304 |
< |
* @param index index of element to return. |
| 305 |
< |
* @return the element at the specified position in this list. |
| 306 |
< |
* |
| 307 |
< |
* @throws IndexOutOfBoundsException if the specified index is is out of |
| 307 |
< |
* range (<tt>index < 0 || index >= size()</tt>). |
| 304 |
> |
* @param index index of element to return |
| 305 |
> |
* @return the element at the specified position in this list |
| 306 |
> |
* @throws IndexOutOfBoundsException if the index is out of range |
| 307 |
> |
* (<tt>index < 0 || index > size()</tt>) |
| 308 |
|
*/ |
| 309 |
|
public E get(int index) { |
| 310 |
|
return entry(index).element; |
| 314 |
|
* Replaces the element at the specified position in this list with the |
| 315 |
|
* specified element. |
| 316 |
|
* |
| 317 |
< |
* @param index index of element to replace. |
| 318 |
< |
* @param element element to be stored at the specified position. |
| 319 |
< |
* @return the element previously at the specified position. |
| 320 |
< |
* @throws IndexOutOfBoundsException if the specified index is out of |
| 321 |
< |
* range (<tt>index < 0 || index >= size()</tt>). |
| 317 |
> |
* @param index index of element to replace |
| 318 |
> |
* @param element element to be stored at the specified position |
| 319 |
> |
* @return the element previously at the specified position |
| 320 |
> |
* @throws IndexOutOfBoundsException if the index is out of range |
| 321 |
> |
* (<tt>index < 0 || index > size()</tt>) |
| 322 |
|
*/ |
| 323 |
|
public E set(int index, E element) { |
| 324 |
|
Entry<E> e = entry(index); |
| 332 |
|
* Shifts the element currently at that position (if any) and any |
| 333 |
|
* subsequent elements to the right (adds one to their indices). |
| 334 |
|
* |
| 335 |
< |
* @param index index at which the specified element is to be inserted. |
| 336 |
< |
* @param element element to be inserted. |
| 335 |
> |
* @param index index at which the specified element is to be inserted |
| 336 |
> |
* @param element element to be inserted |
| 337 |
|
* |
| 338 |
< |
* @throws IndexOutOfBoundsException if the specified index is out of |
| 339 |
< |
* range (<tt>index < 0 || index > size()</tt>). |
| 338 |
> |
* @throws IndexOutOfBoundsException if the index is out of range |
| 339 |
> |
* (<tt>index < 0 || index > size()</tt>) |
| 340 |
|
*/ |
| 341 |
|
public void add(int index, E element) { |
| 342 |
|
addBefore(element, (index==size ? header : entry(index))); |
| 347 |
|
* subsequent elements to the left (subtracts one from their indices). |
| 348 |
|
* Returns the element that was removed from the list. |
| 349 |
|
* |
| 350 |
< |
* @param index the index of the element to removed. |
| 351 |
< |
* @return the element previously at the specified position. |
| 350 |
> |
* @param index the index of the element to be removed |
| 351 |
> |
* @return the element previously at the specified position |
| 352 |
|
* |
| 353 |
< |
* @throws IndexOutOfBoundsException if the specified index is out of |
| 354 |
< |
* range (<tt>index < 0 || index >= size()</tt>). |
| 353 |
> |
* @throws IndexOutOfBoundsException if the index is out of range |
| 354 |
> |
* (<tt>index < 0 || index > size()</tt>) |
| 355 |
|
*/ |
| 356 |
|
public E remove(int index) { |
| 357 |
< |
Entry<E> e = entry(index); |
| 358 |
< |
remove(e); |
| 359 |
< |
return e.element; |
| 357 |
> |
return remove(entry(index)); |
| 358 |
|
} |
| 359 |
|
|
| 360 |
|
/** |
| 361 |
< |
* Return the indexed entry. |
| 361 |
> |
* Returns the indexed entry. |
| 362 |
|
*/ |
| 363 |
|
private Entry<E> entry(int index) { |
| 364 |
|
if (index < 0 || index >= size) |
| 385 |
|
* <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>, or -1 if |
| 386 |
|
* there is no such index. |
| 387 |
|
* |
| 388 |
< |
* @param o element to search for. |
| 388 |
> |
* @param o element to search for |
| 389 |
|
* @return the index in this list of the first occurrence of the |
| 390 |
|
* specified element, or -1 if the list does not contain this |
| 391 |
< |
* element. |
| 391 |
> |
* element |
| 392 |
|
*/ |
| 393 |
|
public int indexOf(Object o) { |
| 394 |
|
int index = 0; |
| 415 |
|
* <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>, or -1 if |
| 416 |
|
* there is no such index. |
| 417 |
|
* |
| 418 |
< |
* @param o element to search for. |
| 418 |
> |
* @param o element to search for |
| 419 |
|
* @return the index in this list of the last occurrence of the |
| 420 |
|
* specified element, or -1 if the list does not contain this |
| 421 |
< |
* element. |
| 421 |
> |
* element |
| 422 |
|
*/ |
| 423 |
|
public int lastIndexOf(Object o) { |
| 424 |
|
int index = size; |
| 442 |
|
|
| 443 |
|
/** |
| 444 |
|
* Retrieves, but does not remove, the head (first element) of this list. |
| 445 |
< |
* @return the head of this queue, or <tt>null</tt> if this queue is empty. |
| 445 |
> |
* @return the head of this list, or <tt>null</tt> if this list is empty |
| 446 |
|
* @since 1.5 |
| 447 |
|
*/ |
| 448 |
|
public E peek() { |
| 453 |
|
|
| 454 |
|
/** |
| 455 |
|
* Retrieves, but does not remove, the head (first element) of this list. |
| 456 |
< |
* @return the head of this queue. |
| 457 |
< |
* @throws NoSuchElementException if this queue is empty. |
| 456 |
> |
* @return the head of this list |
| 457 |
> |
* @throws NoSuchElementException if this list is empty |
| 458 |
|
* @since 1.5 |
| 459 |
|
*/ |
| 460 |
|
public E element() { |
| 462 |
|
} |
| 463 |
|
|
| 464 |
|
/** |
| 465 |
< |
* Retrieves and removes the head (first element) of this list. |
| 466 |
< |
* @return the head of this queue, or <tt>null</tt> if this queue is empty. |
| 465 |
> |
* Retrieves and removes the head (first element) of this list |
| 466 |
> |
* @return the head of this list, or <tt>null</tt> if this list is empty |
| 467 |
|
* @since 1.5 |
| 468 |
|
*/ |
| 469 |
|
public E poll() { |
| 474 |
|
|
| 475 |
|
/** |
| 476 |
|
* Retrieves and removes the head (first element) of this list. |
| 477 |
< |
* @return the head of this queue. |
| 478 |
< |
* @throws NoSuchElementException if this queue is empty. |
| 477 |
> |
* |
| 478 |
> |
* @return the head of this list |
| 479 |
> |
* @throws NoSuchElementException if this list is empty |
| 480 |
|
* @since 1.5 |
| 481 |
|
*/ |
| 482 |
|
public E remove() { |
| 486 |
|
/** |
| 487 |
|
* Adds the specified element as the tail (last element) of this list. |
| 488 |
|
* |
| 489 |
< |
* @param o the element to add. |
| 490 |
< |
* @return <tt>true</tt> (as per the general contract of |
| 492 |
< |
* <tt>Queue.offer</tt>) |
| 489 |
> |
* @param e the element to add |
| 490 |
> |
* @return <tt>true</tt> (as per the spec for {@link Queue#offer}) |
| 491 |
|
* @since 1.5 |
| 492 |
|
*/ |
| 493 |
< |
public boolean offer(E o) { |
| 494 |
< |
return add(o); |
| 493 |
> |
public boolean offer(E e) { |
| 494 |
> |
return add(e); |
| 495 |
> |
} |
| 496 |
> |
|
| 497 |
> |
// Deque operations |
| 498 |
> |
/** |
| 499 |
> |
* Inserts the specified element at the front of this list. |
| 500 |
> |
* |
| 501 |
> |
* @param e the element to insert |
| 502 |
> |
* @return <tt>true</tt> (as per the spec for {@link Deque#offerFirst}) |
| 503 |
> |
* @since 1.6 |
| 504 |
> |
*/ |
| 505 |
> |
public boolean offerFirst(E e) { |
| 506 |
> |
addFirst(e); |
| 507 |
> |
return true; |
| 508 |
> |
} |
| 509 |
> |
|
| 510 |
> |
/** |
| 511 |
> |
* Inserts the specified element at the end of this list. |
| 512 |
> |
* |
| 513 |
> |
* @param e the element to insert |
| 514 |
> |
* @return <tt>true</tt> (as per the spec for {@link Deque#offerLast}) |
| 515 |
> |
* @since 1.6 |
| 516 |
> |
*/ |
| 517 |
> |
public boolean offerLast(E e) { |
| 518 |
> |
addLast(e); |
| 519 |
> |
return true; |
| 520 |
> |
} |
| 521 |
> |
|
| 522 |
> |
/** |
| 523 |
> |
* Retrieves, but does not remove, the first element of this list, |
| 524 |
> |
* or returns <tt>null</tt> if this list is empty. |
| 525 |
> |
* |
| 526 |
> |
* @return the first element of this list, or <tt>null</tt> |
| 527 |
> |
* if this list is empty. |
| 528 |
> |
* @since 1.6 |
| 529 |
> |
*/ |
| 530 |
> |
public E peekFirst() { |
| 531 |
> |
if (size==0) |
| 532 |
> |
return null; |
| 533 |
> |
return getFirst(); |
| 534 |
> |
} |
| 535 |
> |
|
| 536 |
> |
/** |
| 537 |
> |
* Retrieves, but does not remove, the last element of this list, |
| 538 |
> |
* or returns <tt>null</tt> if this list is empty. |
| 539 |
> |
* |
| 540 |
> |
* @return the last element of this list, or <tt>null</tt> |
| 541 |
> |
* if this list is empty. |
| 542 |
> |
* @since 1.6 |
| 543 |
> |
*/ |
| 544 |
> |
public E peekLast() { |
| 545 |
> |
if (size==0) |
| 546 |
> |
return null; |
| 547 |
> |
return getLast(); |
| 548 |
> |
} |
| 549 |
> |
|
| 550 |
> |
/** |
| 551 |
> |
* Retrieves and removes the first element of this list, or |
| 552 |
> |
* <tt>null</tt> if this list is empty. |
| 553 |
> |
* |
| 554 |
> |
* @return the first element of this list, or <tt>null</tt> if |
| 555 |
> |
* this list is empty |
| 556 |
> |
* @since 1.6 |
| 557 |
> |
*/ |
| 558 |
> |
public E pollFirst() { |
| 559 |
> |
if (size==0) |
| 560 |
> |
return null; |
| 561 |
> |
return removeFirst(); |
| 562 |
> |
} |
| 563 |
> |
|
| 564 |
> |
/** |
| 565 |
> |
* Retrieves and removes the last element of this list, or |
| 566 |
> |
* <tt>null</tt> if this list is empty. |
| 567 |
> |
* |
| 568 |
> |
* @return the last element of this list, or <tt>null</tt> if |
| 569 |
> |
* this list is empty |
| 570 |
> |
* @since 1.6 |
| 571 |
> |
*/ |
| 572 |
> |
public E pollLast() { |
| 573 |
> |
if (size==0) |
| 574 |
> |
return null; |
| 575 |
> |
return removeLast(); |
| 576 |
> |
} |
| 577 |
> |
|
| 578 |
> |
/** |
| 579 |
> |
* Pushes an element onto the stack represented by this list. In other |
| 580 |
> |
* words, inserts the element at the front of this list. |
| 581 |
> |
* |
| 582 |
> |
* <p>This method is equivalent to {@link #addFirst}. |
| 583 |
> |
* |
| 584 |
> |
* @param e the element to push |
| 585 |
> |
* @since 1.6 |
| 586 |
> |
*/ |
| 587 |
> |
public void push(E e) { |
| 588 |
> |
addFirst(e); |
| 589 |
> |
} |
| 590 |
> |
|
| 591 |
> |
/** |
| 592 |
> |
* Pops an element from the stack represented by this list. In other |
| 593 |
> |
* words, removes and returns the first element of this list. |
| 594 |
> |
* |
| 595 |
> |
* <p>This method is equivalent to {@link #removeFirst()}. |
| 596 |
> |
* |
| 597 |
> |
* @return the element at the front of this list (which is the top |
| 598 |
> |
* of the stack represented by this list) |
| 599 |
> |
* @throws NoSuchElementException if this list is empty |
| 600 |
> |
* @since 1.6 |
| 601 |
> |
*/ |
| 602 |
> |
public E pop() { |
| 603 |
> |
return removeFirst(); |
| 604 |
> |
} |
| 605 |
> |
|
| 606 |
> |
/** |
| 607 |
> |
* Removes the first occurrence of the specified element in this |
| 608 |
> |
* list (when traversing the list from head to tail). If the list |
| 609 |
> |
* does not contain the element, it is unchanged. |
| 610 |
> |
* |
| 611 |
> |
* @param o element to be removed from this list, if present |
| 612 |
> |
* @return <tt>true</tt> if the list contained the specified element |
| 613 |
> |
* @since 1.6 |
| 614 |
> |
*/ |
| 615 |
> |
public boolean removeFirstOccurrence(Object o) { |
| 616 |
> |
return remove(o); |
| 617 |
> |
} |
| 618 |
> |
|
| 619 |
> |
/** |
| 620 |
> |
* Removes the last occurrence of the specified element in this |
| 621 |
> |
* list (when traversing the list from head to tail). If the list |
| 622 |
> |
* does not contain the element, it is unchanged. |
| 623 |
> |
* |
| 624 |
> |
* @param o element to be removed from this list, if present |
| 625 |
> |
* @return <tt>true</tt> if the list contained the specified element |
| 626 |
> |
* @since 1.6 |
| 627 |
> |
*/ |
| 628 |
> |
public boolean removeLastOccurrence(Object o) { |
| 629 |
> |
if (o==null) { |
| 630 |
> |
for (Entry e = header.previous; e != header; e = e.previous) { |
| 631 |
> |
if (e.element==null) { |
| 632 |
> |
remove(e); |
| 633 |
> |
return true; |
| 634 |
> |
} |
| 635 |
> |
} |
| 636 |
> |
} else { |
| 637 |
> |
for (Entry e = header.previous; e != header; e = e.previous) { |
| 638 |
> |
if (o.equals(e.element)) { |
| 639 |
> |
remove(e); |
| 640 |
> |
return true; |
| 641 |
> |
} |
| 642 |
> |
} |
| 643 |
> |
} |
| 644 |
> |
return false; |
| 645 |
|
} |
| 646 |
|
|
| 647 |
|
/** |
| 658 |
|
* than risking arbitrary, non-deterministic behavior at an undetermined |
| 659 |
|
* time in the future. |
| 660 |
|
* |
| 661 |
< |
* @param index index of first element to be returned from the |
| 661 |
> |
* @param index index of the first element to be returned from the |
| 662 |
|
* list-iterator (by a call to <tt>next</tt>). |
| 663 |
|
* @return a ListIterator of the elements in this list (in proper |
| 664 |
|
* sequence), starting at the specified position in the list. |
| 665 |
< |
* @throws IndexOutOfBoundsException if index is out of range |
| 666 |
< |
* (<tt>index < 0 || index > size()</tt>). |
| 665 |
> |
* @throws IndexOutOfBoundsException if the index is out of range |
| 666 |
> |
* (<tt>index < 0 || index > size()</tt>). |
| 667 |
|
* @see List#listIterator(int) |
| 668 |
|
*/ |
| 669 |
|
public ListIterator<E> listIterator(int index) { |
| 670 |
< |
return new ListItr(index); |
| 670 |
> |
return new ListItr(index); |
| 671 |
|
} |
| 672 |
|
|
| 673 |
|
private class ListItr implements ListIterator<E> { |
| 674 |
< |
private Entry<E> lastReturned = header; |
| 675 |
< |
private Entry<E> next; |
| 676 |
< |
private int nextIndex; |
| 677 |
< |
private int expectedModCount = modCount; |
| 678 |
< |
|
| 679 |
< |
ListItr(int index) { |
| 680 |
< |
if (index < 0 || index > size) |
| 681 |
< |
throw new IndexOutOfBoundsException("Index: "+index+ |
| 682 |
< |
", Size: "+size); |
| 683 |
< |
if (index < (size >> 1)) { |
| 684 |
< |
next = header.next; |
| 685 |
< |
for (nextIndex=0; nextIndex<index; nextIndex++) |
| 686 |
< |
next = next.next; |
| 687 |
< |
} else { |
| 688 |
< |
next = header; |
| 689 |
< |
for (nextIndex=size; nextIndex>index; nextIndex--) |
| 690 |
< |
next = next.previous; |
| 691 |
< |
} |
| 692 |
< |
} |
| 693 |
< |
|
| 694 |
< |
public boolean hasNext() { |
| 695 |
< |
return nextIndex != size; |
| 696 |
< |
} |
| 674 |
> |
private Entry<E> lastReturned = header; |
| 675 |
> |
private Entry<E> next; |
| 676 |
> |
private int nextIndex; |
| 677 |
> |
private int expectedModCount = modCount; |
| 678 |
> |
|
| 679 |
> |
ListItr(int index) { |
| 680 |
> |
if (index < 0 || index > size) |
| 681 |
> |
throw new IndexOutOfBoundsException("Index: "+index+ |
| 682 |
> |
", Size: "+size); |
| 683 |
> |
if (index < (size >> 1)) { |
| 684 |
> |
next = header.next; |
| 685 |
> |
for (nextIndex=0; nextIndex<index; nextIndex++) |
| 686 |
> |
next = next.next; |
| 687 |
> |
} else { |
| 688 |
> |
next = header; |
| 689 |
> |
for (nextIndex=size; nextIndex>index; nextIndex--) |
| 690 |
> |
next = next.previous; |
| 691 |
> |
} |
| 692 |
> |
} |
| 693 |
> |
|
| 694 |
> |
public boolean hasNext() { |
| 695 |
> |
return nextIndex != size; |
| 696 |
> |
} |
| 697 |
> |
|
| 698 |
> |
public E next() { |
| 699 |
> |
checkForComodification(); |
| 700 |
> |
if (nextIndex == size) |
| 701 |
> |
throw new NoSuchElementException(); |
| 702 |
> |
|
| 703 |
> |
lastReturned = next; |
| 704 |
> |
next = next.next; |
| 705 |
> |
nextIndex++; |
| 706 |
> |
return lastReturned.element; |
| 707 |
> |
} |
| 708 |
> |
|
| 709 |
> |
public boolean hasPrevious() { |
| 710 |
> |
return nextIndex != 0; |
| 711 |
> |
} |
| 712 |
> |
|
| 713 |
> |
public E previous() { |
| 714 |
> |
if (nextIndex == 0) |
| 715 |
> |
throw new NoSuchElementException(); |
| 716 |
> |
|
| 717 |
> |
lastReturned = next = next.previous; |
| 718 |
> |
nextIndex--; |
| 719 |
> |
checkForComodification(); |
| 720 |
> |
return lastReturned.element; |
| 721 |
> |
} |
| 722 |
> |
|
| 723 |
> |
public int nextIndex() { |
| 724 |
> |
return nextIndex; |
| 725 |
> |
} |
| 726 |
> |
|
| 727 |
> |
public int previousIndex() { |
| 728 |
> |
return nextIndex-1; |
| 729 |
> |
} |
| 730 |
|
|
| 731 |
< |
public E next() { |
| 551 |
< |
checkForComodification(); |
| 552 |
< |
if (nextIndex == size) |
| 553 |
< |
throw new NoSuchElementException(); |
| 554 |
< |
|
| 555 |
< |
lastReturned = next; |
| 556 |
< |
next = next.next; |
| 557 |
< |
nextIndex++; |
| 558 |
< |
return lastReturned.element; |
| 559 |
< |
} |
| 560 |
< |
|
| 561 |
< |
public boolean hasPrevious() { |
| 562 |
< |
return nextIndex != 0; |
| 563 |
< |
} |
| 564 |
< |
|
| 565 |
< |
public E previous() { |
| 566 |
< |
if (nextIndex == 0) |
| 567 |
< |
throw new NoSuchElementException(); |
| 568 |
< |
|
| 569 |
< |
lastReturned = next = next.previous; |
| 570 |
< |
nextIndex--; |
| 571 |
< |
checkForComodification(); |
| 572 |
< |
return lastReturned.element; |
| 573 |
< |
} |
| 574 |
< |
|
| 575 |
< |
public int nextIndex() { |
| 576 |
< |
return nextIndex; |
| 577 |
< |
} |
| 578 |
< |
|
| 579 |
< |
public int previousIndex() { |
| 580 |
< |
return nextIndex-1; |
| 581 |
< |
} |
| 582 |
< |
|
| 583 |
< |
public void remove() { |
| 731 |
> |
public void remove() { |
| 732 |
|
checkForComodification(); |
| 733 |
+ |
Entry<E> lastNext = lastReturned.next; |
| 734 |
|
try { |
| 735 |
|
LinkedList.this.remove(lastReturned); |
| 736 |
|
} catch (NoSuchElementException e) { |
| 737 |
|
throw new IllegalStateException(); |
| 738 |
|
} |
| 739 |
< |
if (next==lastReturned) |
| 740 |
< |
next = lastReturned.next; |
| 739 |
> |
if (next==lastReturned) |
| 740 |
> |
next = lastNext; |
| 741 |
|
else |
| 742 |
< |
nextIndex--; |
| 743 |
< |
lastReturned = header; |
| 744 |
< |
expectedModCount++; |
| 745 |
< |
} |
| 746 |
< |
|
| 747 |
< |
public void set(E o) { |
| 748 |
< |
if (lastReturned == header) |
| 749 |
< |
throw new IllegalStateException(); |
| 750 |
< |
checkForComodification(); |
| 751 |
< |
lastReturned.element = o; |
| 752 |
< |
} |
| 753 |
< |
|
| 754 |
< |
public void add(E o) { |
| 755 |
< |
checkForComodification(); |
| 756 |
< |
lastReturned = header; |
| 757 |
< |
addBefore(o, next); |
| 758 |
< |
nextIndex++; |
| 759 |
< |
expectedModCount++; |
| 760 |
< |
} |
| 761 |
< |
|
| 762 |
< |
final void checkForComodification() { |
| 763 |
< |
if (modCount != expectedModCount) |
| 764 |
< |
throw new ConcurrentModificationException(); |
| 765 |
< |
} |
| 742 |
> |
nextIndex--; |
| 743 |
> |
lastReturned = header; |
| 744 |
> |
expectedModCount++; |
| 745 |
> |
} |
| 746 |
> |
|
| 747 |
> |
public void set(E e) { |
| 748 |
> |
if (lastReturned == header) |
| 749 |
> |
throw new IllegalStateException(); |
| 750 |
> |
checkForComodification(); |
| 751 |
> |
lastReturned.element = e; |
| 752 |
> |
} |
| 753 |
> |
|
| 754 |
> |
public void add(E e) { |
| 755 |
> |
checkForComodification(); |
| 756 |
> |
lastReturned = header; |
| 757 |
> |
addBefore(e, next); |
| 758 |
> |
nextIndex++; |
| 759 |
> |
expectedModCount++; |
| 760 |
> |
} |
| 761 |
> |
|
| 762 |
> |
final void checkForComodification() { |
| 763 |
> |
if (modCount != expectedModCount) |
| 764 |
> |
throw new ConcurrentModificationException(); |
| 765 |
> |
} |
| 766 |
|
} |
| 767 |
|
|
| 768 |
|
private static class Entry<E> { |
| 769 |
< |
E element; |
| 770 |
< |
Entry<E> next; |
| 771 |
< |
Entry<E> previous; |
| 772 |
< |
|
| 773 |
< |
Entry(E element, Entry<E> next, Entry<E> previous) { |
| 774 |
< |
this.element = element; |
| 775 |
< |
this.next = next; |
| 776 |
< |
this.previous = previous; |
| 777 |
< |
} |
| 778 |
< |
} |
| 779 |
< |
|
| 780 |
< |
private Entry<E> addBefore(E o, Entry<E> e) { |
| 781 |
< |
Entry<E> newEntry = new Entry<E>(o, e, e.previous); |
| 782 |
< |
newEntry.previous.next = newEntry; |
| 783 |
< |
newEntry.next.previous = newEntry; |
| 784 |
< |
size++; |
| 785 |
< |
modCount++; |
| 786 |
< |
return newEntry; |
| 787 |
< |
} |
| 788 |
< |
|
| 789 |
< |
private void remove(Entry<E> e) { |
| 790 |
< |
if (e == header) |
| 791 |
< |
throw new NoSuchElementException(); |
| 792 |
< |
|
| 793 |
< |
e.previous.next = e.next; |
| 794 |
< |
e.next.previous = e.previous; |
| 795 |
< |
size--; |
| 796 |
< |
modCount++; |
| 769 |
> |
E element; |
| 770 |
> |
Entry<E> next; |
| 771 |
> |
Entry<E> previous; |
| 772 |
> |
|
| 773 |
> |
Entry(E element, Entry<E> next, Entry<E> previous) { |
| 774 |
> |
this.element = element; |
| 775 |
> |
this.next = next; |
| 776 |
> |
this.previous = previous; |
| 777 |
> |
} |
| 778 |
> |
} |
| 779 |
> |
|
| 780 |
> |
private Entry<E> addBefore(E e, Entry<E> entry) { |
| 781 |
> |
Entry<E> newEntry = new Entry<E>(e, entry, entry.previous); |
| 782 |
> |
newEntry.previous.next = newEntry; |
| 783 |
> |
newEntry.next.previous = newEntry; |
| 784 |
> |
size++; |
| 785 |
> |
modCount++; |
| 786 |
> |
return newEntry; |
| 787 |
> |
} |
| 788 |
> |
|
| 789 |
> |
private E remove(Entry<E> e) { |
| 790 |
> |
if (e == header) |
| 791 |
> |
throw new NoSuchElementException(); |
| 792 |
> |
|
| 793 |
> |
E result = e.element; |
| 794 |
> |
e.previous.next = e.next; |
| 795 |
> |
e.next.previous = e.previous; |
| 796 |
> |
e.next = e.previous = null; |
| 797 |
> |
e.element = null; |
| 798 |
> |
size--; |
| 799 |
> |
modCount++; |
| 800 |
> |
return result; |
| 801 |
|
} |
| 802 |
|
|
| 803 |
|
/** |
| 804 |
|
* Returns a shallow copy of this <tt>LinkedList</tt>. (The elements |
| 805 |
|
* themselves are not cloned.) |
| 806 |
|
* |
| 807 |
< |
* @return a shallow copy of this <tt>LinkedList</tt> instance. |
| 807 |
> |
* @return a shallow copy of this <tt>LinkedList</tt> instance |
| 808 |
|
*/ |
| 809 |
|
public Object clone() { |
| 810 |
|
LinkedList<E> clone = null; |
| 811 |
< |
try { |
| 812 |
< |
clone = (LinkedList<E>) super.clone(); |
| 813 |
< |
} catch (CloneNotSupportedException e) { |
| 814 |
< |
throw new InternalError(); |
| 815 |
< |
} |
| 811 |
> |
try { |
| 812 |
> |
clone = (LinkedList<E>) super.clone(); |
| 813 |
> |
} catch (CloneNotSupportedException e) { |
| 814 |
> |
throw new InternalError(); |
| 815 |
> |
} |
| 816 |
|
|
| 817 |
|
// Put clone into "virgin" state |
| 818 |
|
clone.header = new Entry<E>(null, null, null); |
| 835 |
|
* in the correct order. |
| 836 |
|
*/ |
| 837 |
|
public Object[] toArray() { |
| 838 |
< |
Object[] result = new Object[size]; |
| 838 |
> |
Object[] result = new Object[size]; |
| 839 |
|
int i = 0; |
| 840 |
|
for (Entry<E> e = header.next; e != header; e = e.next) |
| 841 |
|
result[i++] = e.element; |
| 842 |
< |
return result; |
| 842 |
> |
return result; |
| 843 |
|
} |
| 844 |
|
|
| 845 |
|
/** |
| 859 |
|
* @param a the array into which the elements of the list are to |
| 860 |
|
* be stored, if it is big enough; otherwise, a new array of the |
| 861 |
|
* same runtime type is allocated for this purpose. |
| 862 |
< |
* @return an array containing the elements of the list. |
| 862 |
> |
* @return an array containing the elements of the list |
| 863 |
|
* @throws ArrayStoreException if the runtime type of a is not a |
| 864 |
< |
* supertype of the runtime type of every element in this list. |
| 865 |
< |
* @throws NullPointerException if the specified array is null. |
| 864 |
> |
* supertype of the runtime type of every element in this list |
| 865 |
> |
* @throws NullPointerException if the specified array is null |
| 866 |
|
*/ |
| 867 |
|
public <T> T[] toArray(T[] a) { |
| 868 |
|
if (a.length < size) |
| 869 |
|
a = (T[])java.lang.reflect.Array.newInstance( |
| 870 |
|
a.getClass().getComponentType(), size); |
| 871 |
|
int i = 0; |
| 872 |
< |
Object[] result = a; |
| 872 |
> |
Object[] result = a; |
| 873 |
|
for (Entry<E> e = header.next; e != header; e = e.next) |
| 874 |
|
result[i++] = e.element; |
| 875 |
|
|
| 887 |
|
* |
| 888 |
|
* @serialData The size of the list (the number of elements it |
| 889 |
|
* contains) is emitted (int), followed by all of its |
| 890 |
< |
* elements (each an Object) in the proper order. |
| 890 |
> |
* elements (each an Object) in the proper order. |
| 891 |
|
*/ |
| 892 |
|
private void writeObject(java.io.ObjectOutputStream s) |
| 893 |
|
throws java.io.IOException { |
| 894 |
< |
// Write out any hidden serialization magic |
| 895 |
< |
s.defaultWriteObject(); |
| 894 |
> |
// Write out any hidden serialization magic |
| 895 |
> |
s.defaultWriteObject(); |
| 896 |
|
|
| 897 |
|
// Write out size |
| 898 |
|
s.writeInt(size); |
| 899 |
|
|
| 900 |
< |
// Write out all elements in the proper order. |
| 900 |
> |
// Write out all elements in the proper order. |
| 901 |
|
for (Entry e = header.next; e != header; e = e.next) |
| 902 |
|
s.writeObject(e.element); |
| 903 |
|
} |
| 908 |
|
*/ |
| 909 |
|
private void readObject(java.io.ObjectInputStream s) |
| 910 |
|
throws java.io.IOException, ClassNotFoundException { |
| 911 |
< |
// Read in any hidden serialization magic |
| 912 |
< |
s.defaultReadObject(); |
| 911 |
> |
// Read in any hidden serialization magic |
| 912 |
> |
s.defaultReadObject(); |
| 913 |
|
|
| 914 |
|
// Read in size |
| 915 |
|
int size = s.readInt(); |
| 918 |
|
header = new Entry<E>(null, null, null); |
| 919 |
|
header.next = header.previous = header; |
| 920 |
|
|
| 921 |
< |
// Read in all elements in the proper order. |
| 922 |
< |
for (int i=0; i<size; i++) |
| 921 |
> |
// Read in all elements in the proper order. |
| 922 |
> |
for (int i=0; i<size; i++) |
| 923 |
|
addBefore((E)s.readObject(), header); |
| 924 |
|
} |
| 925 |
|
} |
