| 1 |
|
/* |
| 2 |
< |
* @(#)LinkedList.java 1.43 01/12/03 |
| 2 |
> |
* %W% %E% |
| 3 |
|
* |
| 4 |
< |
* Copyright 2002 Sun Microsystems, Inc. All rights reserved. |
| 4 |
> |
* Copyright 2003 Sun Microsystems, Inc. All rights reserved. |
| 5 |
|
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. |
| 6 |
|
*/ |
| 7 |
|
|
| 8 |
|
package java.util; |
| 9 |
|
|
| 10 |
|
/** |
| 11 |
– |
* <b>JSR166: Added Queue operations</b>.<p> |
| 11 |
|
* Linked list implementation of the <tt>List</tt> interface. Implements all |
| 12 |
|
* optional list operations, and permits all elements (including |
| 13 |
|
* <tt>null</tt>). In addition to implementing the <tt>List</tt> interface, |
| 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> |
| 18 |
|
* |
| 19 |
< |
* All of the stack/queue/deque operations could be easily recast in terms of |
| 20 |
< |
* the standard list operations. They're included here primarily for |
| 21 |
< |
* convenience, though they may run slightly faster than the equivalent List |
| 22 |
< |
* operations.<p> |
| 19 |
> |
* The class implements the <tt>Queue</tt> interface, providing |
| 20 |
> |
* first-in-first-out queue operations for <tt>add</tt>, |
| 21 |
> |
* <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> |
| 25 |
|
* |
| 26 |
|
* All of the operations perform as could be expected for a doubly-linked |
| 27 |
|
* list. Operations that index into the list will traverse the list from |
| 28 |
< |
* the begining or the end, whichever is closer to the specified index.<p> |
| 28 |
> |
* the beginning or the end, whichever is closer to the specified index.<p> |
| 29 |
|
* |
| 30 |
|
* <b>Note that this implementation is not synchronized.</b> If multiple |
| 31 |
|
* threads access a list concurrently, and at least one of the threads |
| 52 |
|
* <p>Note that the fail-fast behavior of an iterator cannot be guaranteed |
| 53 |
|
* as it is, generally speaking, impossible to make any hard guarantees in the |
| 54 |
|
* presence of unsynchronized concurrent modification. Fail-fast iterators |
| 55 |
< |
* throw <tt>ConcurrentModificationException</tt> on a best-effort basis. |
| 55 |
> |
* throw <tt>ConcurrentModificationException</tt> on a best-effort basis. |
| 56 |
|
* Therefore, it would be wrong to write a program that depended on this |
| 57 |
|
* exception for its correctness: <i>the fail-fast behavior of iterators |
| 58 |
< |
* should be used only to detect bugs.</i> |
| 58 |
> |
* should be used only to detect bugs.</i><p> |
| 59 |
> |
* |
| 60 |
> |
* This class is a member of the |
| 61 |
> |
* <a href="{@docRoot}/../guide/collections/index.html"> |
| 62 |
> |
* Java Collections Framework</a>. |
| 63 |
|
* |
| 64 |
|
* @author Josh Bloch |
| 65 |
< |
* @version 1.43, 12/03/01 |
| 66 |
< |
* @see java.util.List |
| 67 |
< |
* @see java.util.ArrayList |
| 68 |
< |
* @see java.util.Vector |
| 69 |
< |
* @see java.util.Collections#synchronizedList(java.util.List) |
| 65 |
> |
* @version %I%, %G% |
| 66 |
> |
* @see List |
| 67 |
> |
* @see ArrayList |
| 68 |
> |
* @see Vector |
| 69 |
> |
* @see Collections#synchronizedList(List) |
| 70 |
|
* @since 1.2 |
| 71 |
+ |
* @param <E> the type of elements held in this collection |
| 72 |
|
*/ |
| 73 |
|
|
| 74 |
< |
public class LinkedList extends AbstractSequentialList |
| 75 |
< |
implements List, Queue, Cloneable, java.io.Serializable |
| 74 |
> |
public class LinkedList<E> |
| 75 |
> |
extends AbstractSequentialList<E> |
| 76 |
> |
implements List<E>, Queue<E>, Cloneable, java.io.Serializable |
| 77 |
|
{ |
| 78 |
< |
private transient Entry header = new Entry(null, null, null); |
| 78 |
> |
private transient Entry<E> header = new Entry<E>(null, null, null); |
| 79 |
|
private transient int size = 0; |
| 80 |
|
|
| 81 |
|
/** |
| 93 |
|
* @param c the collection whose elements are to be placed into this list. |
| 94 |
|
* @throws NullPointerException if the specified collection is null. |
| 95 |
|
*/ |
| 96 |
< |
public LinkedList(Collection c) { |
| 97 |
< |
this(); |
| 98 |
< |
addAll(c); |
| 99 |
< |
} |
| 96 |
> |
public LinkedList(Collection<? extends E> c) { |
| 97 |
> |
this(); |
| 98 |
> |
addAll(c); |
| 99 |
> |
} |
| 100 |
|
|
| 101 |
|
/** |
| 102 |
|
* Returns the first element in this list. |
| 104 |
|
* @return the first element in this list. |
| 105 |
|
* @throws NoSuchElementException if this list is empty. |
| 106 |
|
*/ |
| 107 |
< |
public Object getFirst() { |
| 107 |
> |
public E getFirst() { |
| 108 |
|
if (size==0) |
| 109 |
|
throw new NoSuchElementException(); |
| 110 |
|
|
| 117 |
|
* @return the last element in this list. |
| 118 |
|
* @throws NoSuchElementException if this list is empty. |
| 119 |
|
*/ |
| 120 |
< |
public Object getLast() { |
| 120 |
> |
public E getLast() { |
| 121 |
|
if (size==0) |
| 122 |
|
throw new NoSuchElementException(); |
| 123 |
|
|
| 130 |
|
* @return the first element from this list. |
| 131 |
|
* @throws NoSuchElementException if this list is empty. |
| 132 |
|
*/ |
| 133 |
< |
public Object removeFirst() { |
| 134 |
< |
Object first = header.next.element; |
| 133 |
> |
public E removeFirst() { |
| 134 |
> |
E first = header.next.element; |
| 135 |
|
remove(header.next); |
| 136 |
|
return first; |
| 137 |
|
} |
| 142 |
|
* @return the last element from this list. |
| 143 |
|
* @throws NoSuchElementException if this list is empty. |
| 144 |
|
*/ |
| 145 |
< |
public Object removeLast() { |
| 146 |
< |
Object last = header.previous.element; |
| 145 |
> |
public E removeLast() { |
| 146 |
> |
E last = header.previous.element; |
| 147 |
|
remove(header.previous); |
| 148 |
|
return last; |
| 149 |
|
} |
| 150 |
|
|
| 151 |
|
/** |
| 152 |
|
* Inserts the given element at the beginning of this list. |
| 153 |
< |
* |
| 153 |
> |
* |
| 154 |
|
* @param o the element to be inserted at the beginning of this list. |
| 155 |
|
*/ |
| 156 |
< |
public void addFirst(Object o) { |
| 156 |
> |
public void addFirst(E o) { |
| 157 |
|
addBefore(o, header.next); |
| 158 |
|
} |
| 159 |
|
|
| 160 |
|
/** |
| 161 |
|
* Appends the given element to the end of this list. (Identical in |
| 162 |
|
* function to the <tt>add</tt> method; included only for consistency.) |
| 163 |
< |
* |
| 163 |
> |
* |
| 164 |
|
* @param o the element to be inserted at the end of this list. |
| 165 |
|
*/ |
| 166 |
< |
public void addLast(Object o) { |
| 166 |
> |
public void addLast(E o) { |
| 167 |
|
addBefore(o, header); |
| 168 |
|
} |
| 169 |
|
|
| 196 |
|
* @return <tt>true</tt> (as per the general contract of |
| 197 |
|
* <tt>Collection.add</tt>). |
| 198 |
|
*/ |
| 199 |
< |
public boolean add(Object o) { |
| 199 |
> |
public boolean add(E o) { |
| 200 |
|
addBefore(o, header); |
| 201 |
|
return true; |
| 202 |
|
} |
| 213 |
|
*/ |
| 214 |
|
public boolean remove(Object o) { |
| 215 |
|
if (o==null) { |
| 216 |
< |
for (Entry e = header.next; e != header; e = e.next) { |
| 216 |
> |
for (Entry<E> e = header.next; e != header; e = e.next) { |
| 217 |
|
if (e.element==null) { |
| 218 |
|
remove(e); |
| 219 |
|
return true; |
| 220 |
|
} |
| 221 |
|
} |
| 222 |
|
} else { |
| 223 |
< |
for (Entry e = header.next; e != header; e = e.next) { |
| 223 |
> |
for (Entry<E> e = header.next; e != header; e = e.next) { |
| 224 |
|
if (o.equals(e.element)) { |
| 225 |
|
remove(e); |
| 226 |
|
return true; |
| 242 |
|
* @return <tt>true</tt> if this list changed as a result of the call. |
| 243 |
|
* @throws NullPointerException if the specified collection is null. |
| 244 |
|
*/ |
| 245 |
< |
public boolean addAll(Collection c) { |
| 245 |
> |
public boolean addAll(Collection<? extends E> c) { |
| 246 |
|
return addAll(size, c); |
| 247 |
|
} |
| 248 |
|
|
| 262 |
|
* range (<tt>index < 0 || index > size()</tt>). |
| 263 |
|
* @throws NullPointerException if the specified collection is null. |
| 264 |
|
*/ |
| 265 |
< |
public boolean addAll(int index, Collection c) { |
| 266 |
< |
int numNew = c.size(); |
| 267 |
< |
if (numNew==0) { |
| 268 |
< |
if (index < 0 || index >= size) |
| 269 |
< |
throw new IndexOutOfBoundsException(); |
| 270 |
< |
else |
| 271 |
< |
return false; |
| 272 |
< |
} |
| 265 |
> |
public boolean addAll(int index, Collection<? extends E> c) { |
| 266 |
> |
if (index < 0 || index > size) |
| 267 |
> |
throw new IndexOutOfBoundsException("Index: "+index+ |
| 268 |
> |
", Size: "+size); |
| 269 |
> |
Object[] a = c.toArray(); |
| 270 |
> |
int numNew = a.length; |
| 271 |
> |
if (numNew==0) |
| 272 |
> |
return false; |
| 273 |
|
modCount++; |
| 274 |
|
|
| 275 |
< |
Entry successor = (index==size ? header : entry(index)); |
| 276 |
< |
Entry predecessor = successor.previous; |
| 270 |
< |
Iterator it = c.iterator(); |
| 275 |
> |
Entry<E> successor = (index==size ? header : entry(index)); |
| 276 |
> |
Entry<E> predecessor = successor.previous; |
| 277 |
|
for (int i=0; i<numNew; i++) { |
| 278 |
< |
Entry e = new Entry(it.next(), successor, predecessor); |
| 278 |
> |
Entry<E> e = new Entry<E>((E)a[i], successor, predecessor); |
| 279 |
|
predecessor.next = e; |
| 280 |
|
predecessor = e; |
| 281 |
|
} |
| 302 |
|
* |
| 303 |
|
* @param index index of element to return. |
| 304 |
|
* @return the element at the specified position in this list. |
| 305 |
< |
* |
| 305 |
> |
* |
| 306 |
|
* @throws IndexOutOfBoundsException if the specified index is is out of |
| 307 |
|
* range (<tt>index < 0 || index >= size()</tt>). |
| 308 |
|
*/ |
| 309 |
< |
public Object get(int index) { |
| 309 |
> |
public E get(int index) { |
| 310 |
|
return entry(index).element; |
| 311 |
|
} |
| 312 |
|
|
| 320 |
|
* @throws IndexOutOfBoundsException if the specified index is out of |
| 321 |
|
* range (<tt>index < 0 || index >= size()</tt>). |
| 322 |
|
*/ |
| 323 |
< |
public Object set(int index, Object element) { |
| 324 |
< |
Entry e = entry(index); |
| 325 |
< |
Object oldVal = e.element; |
| 323 |
> |
public E set(int index, E element) { |
| 324 |
> |
Entry<E> e = entry(index); |
| 325 |
> |
E oldVal = e.element; |
| 326 |
|
e.element = element; |
| 327 |
|
return oldVal; |
| 328 |
|
} |
| 334 |
|
* |
| 335 |
|
* @param index index at which the specified element is to be inserted. |
| 336 |
|
* @param element element to be inserted. |
| 337 |
< |
* |
| 337 |
> |
* |
| 338 |
|
* @throws IndexOutOfBoundsException if the specified index is out of |
| 339 |
|
* range (<tt>index < 0 || index > size()</tt>). |
| 340 |
|
*/ |
| 341 |
< |
public void add(int index, Object element) { |
| 341 |
> |
public void add(int index, E element) { |
| 342 |
|
addBefore(element, (index==size ? header : entry(index))); |
| 343 |
|
} |
| 344 |
|
|
| 349 |
|
* |
| 350 |
|
* @param index the index of the element to removed. |
| 351 |
|
* @return the element previously at the specified position. |
| 352 |
< |
* |
| 352 |
> |
* |
| 353 |
|
* @throws IndexOutOfBoundsException if the specified index is out of |
| 354 |
|
* range (<tt>index < 0 || index >= size()</tt>). |
| 355 |
|
*/ |
| 356 |
< |
public Object remove(int index) { |
| 357 |
< |
Entry e = entry(index); |
| 356 |
> |
public E remove(int index) { |
| 357 |
> |
Entry<E> e = entry(index); |
| 358 |
|
remove(e); |
| 359 |
|
return e.element; |
| 360 |
|
} |
| 362 |
|
/** |
| 363 |
|
* Return the indexed entry. |
| 364 |
|
*/ |
| 365 |
< |
private Entry entry(int index) { |
| 365 |
> |
private Entry<E> entry(int index) { |
| 366 |
|
if (index < 0 || index >= size) |
| 367 |
|
throw new IndexOutOfBoundsException("Index: "+index+ |
| 368 |
|
", Size: "+size); |
| 369 |
< |
Entry e = header; |
| 369 |
> |
Entry<E> e = header; |
| 370 |
|
if (index < (size >> 1)) { |
| 371 |
|
for (int i = 0; i <= index; i++) |
| 372 |
|
e = e.next; |
| 440 |
|
return -1; |
| 441 |
|
} |
| 442 |
|
|
| 443 |
+ |
// Queue operations. |
| 444 |
+ |
|
| 445 |
+ |
/** |
| 446 |
+ |
* Retrieves, but does not remove, the head (first element) of this list. |
| 447 |
+ |
* @return the head of this queue, or <tt>null</tt> if this queue is empty. |
| 448 |
+ |
* @since 1.5 |
| 449 |
+ |
*/ |
| 450 |
+ |
public E peek() { |
| 451 |
+ |
if (size==0) |
| 452 |
+ |
return null; |
| 453 |
+ |
return getFirst(); |
| 454 |
+ |
} |
| 455 |
+ |
|
| 456 |
+ |
/** |
| 457 |
+ |
* Retrieves, but does not remove, the head (first element) of this list. |
| 458 |
+ |
* @return the head of this queue. |
| 459 |
+ |
* @throws NoSuchElementException if this queue is empty. |
| 460 |
+ |
* @since 1.5 |
| 461 |
+ |
*/ |
| 462 |
+ |
public E element() { |
| 463 |
+ |
return getFirst(); |
| 464 |
+ |
} |
| 465 |
+ |
|
| 466 |
+ |
/** |
| 467 |
+ |
* Retrieves and removes the head (first element) of this list. |
| 468 |
+ |
* @return the head of this queue, or <tt>null</tt> if this queue is empty. |
| 469 |
+ |
* @since 1.5 |
| 470 |
+ |
*/ |
| 471 |
+ |
public E poll() { |
| 472 |
+ |
if (size==0) |
| 473 |
+ |
return null; |
| 474 |
+ |
return removeFirst(); |
| 475 |
+ |
} |
| 476 |
+ |
|
| 477 |
+ |
/** |
| 478 |
+ |
* Retrieves and removes the head (first element) of this list. |
| 479 |
+ |
* @return the head of this queue. |
| 480 |
+ |
* @throws NoSuchElementException if this queue is empty. |
| 481 |
+ |
* @since 1.5 |
| 482 |
+ |
*/ |
| 483 |
+ |
public E remove() { |
| 484 |
+ |
return removeFirst(); |
| 485 |
+ |
} |
| 486 |
+ |
|
| 487 |
+ |
/** |
| 488 |
+ |
* Adds the specified element as the tail (last element) of this list. |
| 489 |
+ |
* |
| 490 |
+ |
* @param o the element to add. |
| 491 |
+ |
* @return <tt>true</tt> (as per the general contract of |
| 492 |
+ |
* <tt>Queue.offer</tt>) |
| 493 |
+ |
* @since 1.5 |
| 494 |
+ |
*/ |
| 495 |
+ |
public boolean offer(E o) { |
| 496 |
+ |
return add(o); |
| 497 |
+ |
} |
| 498 |
+ |
|
| 499 |
|
/** |
| 500 |
|
* Returns a list-iterator of the elements in this list (in proper |
| 501 |
|
* sequence), starting at the specified position in the list. |
| 516 |
|
* sequence), starting at the specified position in the list. |
| 517 |
|
* @throws IndexOutOfBoundsException if index is out of range |
| 518 |
|
* (<tt>index < 0 || index > size()</tt>). |
| 519 |
< |
* @see java.util.List#listIterator(int) |
| 519 |
> |
* @see List#listIterator(int) |
| 520 |
|
*/ |
| 521 |
< |
public ListIterator listIterator(int index) { |
| 521 |
> |
public ListIterator<E> listIterator(int index) { |
| 522 |
|
return new ListItr(index); |
| 523 |
|
} |
| 524 |
|
|
| 525 |
< |
private class ListItr implements ListIterator { |
| 526 |
< |
private Entry lastReturned = header; |
| 527 |
< |
private Entry next; |
| 525 |
> |
private class ListItr implements ListIterator<E> { |
| 526 |
> |
private Entry<E> lastReturned = header; |
| 527 |
> |
private Entry<E> next; |
| 528 |
|
private int nextIndex; |
| 529 |
|
private int expectedModCount = modCount; |
| 530 |
|
|
| 547 |
|
return nextIndex != size; |
| 548 |
|
} |
| 549 |
|
|
| 550 |
< |
public Object next() { |
| 550 |
> |
public E next() { |
| 551 |
|
checkForComodification(); |
| 552 |
|
if (nextIndex == size) |
| 553 |
|
throw new NoSuchElementException(); |
| 562 |
|
return nextIndex != 0; |
| 563 |
|
} |
| 564 |
|
|
| 565 |
< |
public Object previous() { |
| 565 |
> |
public E previous() { |
| 566 |
|
if (nextIndex == 0) |
| 567 |
|
throw new NoSuchElementException(); |
| 568 |
|
|
| 595 |
|
expectedModCount++; |
| 596 |
|
} |
| 597 |
|
|
| 598 |
< |
public void set(Object o) { |
| 598 |
> |
public void set(E o) { |
| 599 |
|
if (lastReturned == header) |
| 600 |
|
throw new IllegalStateException(); |
| 601 |
|
checkForComodification(); |
| 602 |
|
lastReturned.element = o; |
| 603 |
|
} |
| 604 |
|
|
| 605 |
< |
public void add(Object o) { |
| 605 |
> |
public void add(E o) { |
| 606 |
|
checkForComodification(); |
| 607 |
|
lastReturned = header; |
| 608 |
|
addBefore(o, next); |
| 616 |
|
} |
| 617 |
|
} |
| 618 |
|
|
| 619 |
< |
private static class Entry { |
| 620 |
< |
Object element; |
| 621 |
< |
Entry next; |
| 622 |
< |
Entry previous; |
| 619 |
> |
private static class Entry<E> { |
| 620 |
> |
E element; |
| 621 |
> |
Entry<E> next; |
| 622 |
> |
Entry<E> previous; |
| 623 |
|
|
| 624 |
< |
Entry(Object element, Entry next, Entry previous) { |
| 624 |
> |
Entry(E element, Entry<E> next, Entry<E> previous) { |
| 625 |
|
this.element = element; |
| 626 |
|
this.next = next; |
| 627 |
|
this.previous = previous; |
| 628 |
|
} |
| 629 |
|
} |
| 630 |
|
|
| 631 |
< |
private Entry addBefore(Object o, Entry e) { |
| 632 |
< |
Entry newEntry = new Entry(o, e, e.previous); |
| 631 |
> |
private Entry<E> addBefore(E o, Entry<E> e) { |
| 632 |
> |
Entry<E> newEntry = new Entry<E>(o, e, e.previous); |
| 633 |
|
newEntry.previous.next = newEntry; |
| 634 |
|
newEntry.next.previous = newEntry; |
| 635 |
|
size++; |
| 637 |
|
return newEntry; |
| 638 |
|
} |
| 639 |
|
|
| 640 |
< |
private void remove(Entry e) { |
| 640 |
> |
private void remove(Entry<E> e) { |
| 641 |
|
if (e == header) |
| 642 |
|
throw new NoSuchElementException(); |
| 643 |
|
|
| 654 |
|
* @return a shallow copy of this <tt>LinkedList</tt> instance. |
| 655 |
|
*/ |
| 656 |
|
public Object clone() { |
| 657 |
< |
LinkedList clone = null; |
| 658 |
< |
try { |
| 659 |
< |
clone = (LinkedList)super.clone(); |
| 660 |
< |
} catch (CloneNotSupportedException e) { |
| 657 |
> |
LinkedList<E> clone = null; |
| 658 |
> |
try { |
| 659 |
> |
clone = (LinkedList<E>) super.clone(); |
| 660 |
> |
} catch (CloneNotSupportedException e) { |
| 661 |
|
throw new InternalError(); |
| 662 |
|
} |
| 663 |
|
|
| 664 |
|
// Put clone into "virgin" state |
| 665 |
< |
clone.header = new Entry(null, null, null); |
| 665 |
> |
clone.header = new Entry<E>(null, null, null); |
| 666 |
|
clone.header.next = clone.header.previous = clone.header; |
| 667 |
|
clone.size = 0; |
| 668 |
|
clone.modCount = 0; |
| 669 |
|
|
| 670 |
|
// Initialize clone with our elements |
| 671 |
< |
for (Entry e = header.next; e != header; e = e.next) |
| 671 |
> |
for (Entry<E> e = header.next; e != header; e = e.next) |
| 672 |
|
clone.add(e.element); |
| 673 |
|
|
| 674 |
|
return clone; |
| 684 |
|
public Object[] toArray() { |
| 685 |
|
Object[] result = new Object[size]; |
| 686 |
|
int i = 0; |
| 687 |
< |
for (Entry e = header.next; e != header; e = e.next) |
| 687 |
> |
for (Entry<E> e = header.next; e != header; e = e.next) |
| 688 |
|
result[i++] = e.element; |
| 689 |
|
return result; |
| 690 |
|
} |
| 711 |
|
* supertype of the runtime type of every element in this list. |
| 712 |
|
* @throws NullPointerException if the specified array is null. |
| 713 |
|
*/ |
| 714 |
< |
public Object[] toArray(Object a[]) { |
| 714 |
> |
public <T> T[] toArray(T[] a) { |
| 715 |
|
if (a.length < size) |
| 716 |
< |
a = (Object[])java.lang.reflect.Array.newInstance( |
| 716 |
> |
a = (T[])java.lang.reflect.Array.newInstance( |
| 717 |
|
a.getClass().getComponentType(), size); |
| 718 |
|
int i = 0; |
| 719 |
< |
for (Entry e = header.next; e != header; e = e.next) |
| 720 |
< |
a[i++] = e.element; |
| 719 |
> |
Object[] result = a; |
| 720 |
> |
for (Entry<E> e = header.next; e != header; e = e.next) |
| 721 |
> |
result[i++] = e.element; |
| 722 |
|
|
| 723 |
|
if (a.length > size) |
| 724 |
|
a[size] = null; |
| 734 |
|
* |
| 735 |
|
* @serialData The size of the list (the number of elements it |
| 736 |
|
* contains) is emitted (int), followed by all of its |
| 737 |
< |
* elements (each an Object) in the proper order. |
| 737 |
> |
* elements (each an Object) in the proper order. |
| 738 |
|
*/ |
| 739 |
< |
private synchronized void writeObject(java.io.ObjectOutputStream s) |
| 739 |
> |
private void writeObject(java.io.ObjectOutputStream s) |
| 740 |
|
throws java.io.IOException { |
| 741 |
|
// Write out any hidden serialization magic |
| 742 |
|
s.defaultWriteObject(); |
| 753 |
|
* Reconstitute this <tt>LinkedList</tt> instance from a stream (that is |
| 754 |
|
* deserialize it). |
| 755 |
|
*/ |
| 756 |
< |
private synchronized void readObject(java.io.ObjectInputStream s) |
| 756 |
> |
private void readObject(java.io.ObjectInputStream s) |
| 757 |
|
throws java.io.IOException, ClassNotFoundException { |
| 758 |
|
// Read in any hidden serialization magic |
| 759 |
|
s.defaultReadObject(); |
| 762 |
|
int size = s.readInt(); |
| 763 |
|
|
| 764 |
|
// Initialize header |
| 765 |
< |
header = new Entry(null, null, null); |
| 765 |
> |
header = new Entry<E>(null, null, null); |
| 766 |
|
header.next = header.previous = header; |
| 767 |
|
|
| 768 |
|
// Read in all elements in the proper order. |
| 769 |
|
for (int i=0; i<size; i++) |
| 770 |
< |
add(s.readObject()); |
| 770 |
> |
addBefore((E)s.readObject(), header); |
| 771 |
|
} |
| 709 |
– |
|
| 710 |
– |
public Object peek() { |
| 711 |
– |
if (size==0) |
| 712 |
– |
return null; |
| 713 |
– |
return getFirst(); |
| 714 |
– |
} |
| 715 |
– |
|
| 716 |
– |
public Object element() { |
| 717 |
– |
return getFirst(); |
| 718 |
– |
} |
| 719 |
– |
|
| 720 |
– |
public Object poll() { |
| 721 |
– |
if (size==0) |
| 722 |
– |
return null; |
| 723 |
– |
return removeFirst(); |
| 724 |
– |
} |
| 725 |
– |
|
| 726 |
– |
public Object remove() { |
| 727 |
– |
return removeFirst(); |
| 728 |
– |
} |
| 729 |
– |
|
| 730 |
– |
public boolean offer(Object x) { |
| 731 |
– |
return add(x); |
| 732 |
– |
} |
| 733 |
– |
|
| 772 |
|
} |
