1 /*
2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
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10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
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20 *
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24 */
25
26 package java.util;
27
28 import java.util.function.UnaryOperator;
29
30 /**
31 * An ordered collection (also known as a <i>sequence</i>). The user of this
32 * interface has precise control over where in the list each element is
33 * inserted. The user can access elements by their integer index (position in
34 * the list), and search for elements in the list.<p>
35 *
36 * Unlike sets, lists typically allow duplicate elements. More formally,
37 * lists typically allow pairs of elements {@code e1} and {@code e2}
38 * such that {@code e1.equals(e2)}, and they typically allow multiple
39 * null elements if they allow null elements at all. It is not inconceivable
40 * that someone might wish to implement a list that prohibits duplicates, by
41 * throwing runtime exceptions when the user attempts to insert them, but we
42 * expect this usage to be rare.<p>
43 *
44 * The {@code List} interface places additional stipulations, beyond those
45 * specified in the {@code Collection} interface, on the contracts of the
46 * {@code iterator}, {@code add}, {@code remove}, {@code equals}, and
47 * {@code hashCode} methods. Declarations for other inherited methods are
48 * also included here for convenience.<p>
49 *
50 * The {@code List} interface provides four methods for positional (indexed)
51 * access to list elements. Lists (like Java arrays) are zero based. Note
52 * that these operations may execute in time proportional to the index value
53 * for some implementations (the {@code LinkedList} class, for
54 * example). Thus, iterating over the elements in a list is typically
55 * preferable to indexing through it if the caller does not know the
56 * implementation.<p>
57 *
58 * The {@code List} interface provides a special iterator, called a
59 * {@code ListIterator}, that allows element insertion and replacement, and
60 * bidirectional access in addition to the normal operations that the
61 * {@code Iterator} interface provides. A method is provided to obtain a
62 * list iterator that starts at a specified position in the list.<p>
63 *
64 * The {@code List} interface provides two methods to search for a specified
65 * object. From a performance standpoint, these methods should be used with
66 * caution. In many implementations they will perform costly linear
67 * searches.<p>
68 *
69 * The {@code List} interface provides two methods to efficiently insert and
70 * remove multiple elements at an arbitrary point in the list.<p>
71 *
72 * Note: While it is permissible for lists to contain themselves as elements,
73 * extreme caution is advised: the {@code equals} and {@code hashCode}
74 * methods are no longer well defined on such a list.
75 *
76 * <p>Some list implementations have restrictions on the elements that
77 * they may contain. For example, some implementations prohibit null elements,
78 * and some have restrictions on the types of their elements. Attempting to
79 * add an ineligible element throws an unchecked exception, typically
80 * {@code NullPointerException} or {@code ClassCastException}. Attempting
81 * to query the presence of an ineligible element may throw an exception,
82 * or it may simply return false; some implementations will exhibit the former
83 * behavior and some will exhibit the latter. More generally, attempting an
84 * operation on an ineligible element whose completion would not result in
85 * the insertion of an ineligible element into the list may throw an
86 * exception or it may succeed, at the option of the implementation.
87 * Such exceptions are marked as "optional" in the specification for this
88 * interface.
89 *
90 * <p>This interface is a member of the
91 * <a href="{@docRoot}/../technotes/guides/collections/index.html">
92 * Java Collections Framework</a>.
93 *
94 * @param <E> the type of elements in this list
95 *
96 * @author Josh Bloch
97 * @author Neal Gafter
98 * @see Collection
99 * @see Set
100 * @see ArrayList
101 * @see LinkedList
102 * @see Vector
103 * @see Arrays#asList(Object[])
104 * @see Collections#nCopies(int, Object)
105 * @see Collections#EMPTY_LIST
106 * @see AbstractList
107 * @see AbstractSequentialList
108 * @since 1.2
109 */
110
111 public interface List<E> extends Collection<E> {
112 // Query Operations
113
114 /**
115 * Returns the number of elements in this list. If this list contains
116 * more than {@code Integer.MAX_VALUE} elements, returns
117 * {@code Integer.MAX_VALUE}.
118 *
119 * @return the number of elements in this list
120 */
121 int size();
122
123 /**
124 * Returns {@code true} if this list contains no elements.
125 *
126 * @return {@code true} if this list contains no elements
127 */
128 boolean isEmpty();
129
130 /**
131 * Returns {@code true} if this list contains the specified element.
132 * More formally, returns {@code true} if and only if this list contains
133 * at least one element {@code e} such that
134 * {@code Objects.equals(o, e)}.
135 *
136 * @param o element whose presence in this list is to be tested
137 * @return {@code true} if this list contains the specified element
138 * @throws ClassCastException if the type of the specified element
139 * is incompatible with this list
140 * (<a href="Collection.html#optional-restrictions">optional</a>)
141 * @throws NullPointerException if the specified element is null and this
142 * list does not permit null elements
143 * (<a href="Collection.html#optional-restrictions">optional</a>)
144 */
145 boolean contains(Object o);
146
147 /**
148 * Returns an iterator over the elements in this list in proper sequence.
149 *
150 * @return an iterator over the elements in this list in proper sequence
151 */
152 Iterator<E> iterator();
153
154 /**
155 * Returns an array containing all of the elements in this list in proper
156 * sequence (from first to last element).
157 *
158 * <p>The returned array will be "safe" in that no references to it are
159 * maintained by this list. (In other words, this method must
160 * allocate a new array even if this list is backed by an array).
161 * The caller is thus free to modify the returned array.
162 *
163 * <p>This method acts as bridge between array-based and collection-based
164 * APIs.
165 *
166 * @return an array containing all of the elements in this list in proper
167 * sequence
168 * @see Arrays#asList(Object[])
169 */
170 Object[] toArray();
171
172 /**
173 * Returns an array containing all of the elements in this list in
174 * proper sequence (from first to last element); the runtime type of
175 * the returned array is that of the specified array. If the list fits
176 * in the specified array, it is returned therein. Otherwise, a new
177 * array is allocated with the runtime type of the specified array and
178 * the size of this list.
179 *
180 * <p>If the list fits in the specified array with room to spare (i.e.,
181 * the array has more elements than the list), the element in the array
182 * immediately following the end of the list is set to {@code null}.
183 * (This is useful in determining the length of the list <i>only</i> if
184 * the caller knows that the list does not contain any null elements.)
185 *
186 * <p>Like the {@link #toArray()} method, this method acts as bridge between
187 * array-based and collection-based APIs. Further, this method allows
188 * precise control over the runtime type of the output array, and may,
189 * under certain circumstances, be used to save allocation costs.
190 *
191 * <p>Suppose {@code x} is a list known to contain only strings.
192 * The following code can be used to dump the list into a newly
193 * allocated array of {@code String}:
194 *
195 * <pre>{@code
196 * String[] y = x.toArray(new String[0]);
197 * }</pre>
198 *
199 * Note that {@code toArray(new Object[0])} is identical in function to
200 * {@code toArray()}.
201 *
202 * @param a the array into which the elements of this list are to
203 * be stored, if it is big enough; otherwise, a new array of the
204 * same runtime type is allocated for this purpose.
205 * @return an array containing the elements of this list
206 * @throws ArrayStoreException if the runtime type of the specified array
207 * is not a supertype of the runtime type of every element in
208 * this list
209 * @throws NullPointerException if the specified array is null
210 */
211 <T> T[] toArray(T[] a);
212
213
214 // Modification Operations
215
216 /**
217 * Appends the specified element to the end of this list (optional
218 * operation).
219 *
220 * <p>Lists that support this operation may place limitations on what
221 * elements may be added to this list. In particular, some
222 * lists will refuse to add null elements, and others will impose
223 * restrictions on the type of elements that may be added. List
224 * classes should clearly specify in their documentation any restrictions
225 * on what elements may be added.
226 *
227 * @param e element to be appended to this list
228 * @return {@code true} (as specified by {@link Collection#add})
229 * @throws UnsupportedOperationException if the {@code add} operation
230 * is not supported by this list
231 * @throws ClassCastException if the class of the specified element
232 * prevents it from being added to this list
233 * @throws NullPointerException if the specified element is null and this
234 * list does not permit null elements
235 * @throws IllegalArgumentException if some property of this element
236 * prevents it from being added to this list
237 */
238 boolean add(E e);
239
240 /**
241 * Removes the first occurrence of the specified element from this list,
242 * if it is present (optional operation). If this list does not contain
243 * the element, it is unchanged. More formally, removes the element with
244 * the lowest index {@code i} such that
245 * {@code Objects.equals(o, get(i))}
246 * (if such an element exists). Returns {@code true} if this list
247 * contained the specified element (or equivalently, if this list changed
248 * as a result of the call).
249 *
250 * @param o element to be removed from this list, if present
251 * @return {@code true} if this list contained the specified element
252 * @throws ClassCastException if the type of the specified element
253 * is incompatible with this list
254 * (<a href="Collection.html#optional-restrictions">optional</a>)
255 * @throws NullPointerException if the specified element is null and this
256 * list does not permit null elements
257 * (<a href="Collection.html#optional-restrictions">optional</a>)
258 * @throws UnsupportedOperationException if the {@code remove} operation
259 * is not supported by this list
260 */
261 boolean remove(Object o);
262
263
264 // Bulk Modification Operations
265
266 /**
267 * Returns {@code true} if this list contains all of the elements of the
268 * specified collection.
269 *
270 * @param c collection to be checked for containment in this list
271 * @return {@code true} if this list contains all of the elements of the
272 * specified collection
273 * @throws ClassCastException if the types of one or more elements
274 * in the specified collection are incompatible with this
275 * list
276 * (<a href="Collection.html#optional-restrictions">optional</a>)
277 * @throws NullPointerException if the specified collection contains one
278 * or more null elements and this list does not permit null
279 * elements
280 * (<a href="Collection.html#optional-restrictions">optional</a>),
281 * or if the specified collection is null
282 * @see #contains(Object)
283 */
284 boolean containsAll(Collection<?> c);
285
286 /**
287 * Appends all of the elements in the specified collection to the end of
288 * this list, in the order that they are returned by the specified
289 * collection's iterator (optional operation). The behavior of this
290 * operation is undefined if the specified collection is modified while
291 * the operation is in progress. (Note that this will occur if the
292 * specified collection is this list, and it's nonempty.)
293 *
294 * @param c collection containing elements to be added to this list
295 * @return {@code true} if this list changed as a result of the call
296 * @throws UnsupportedOperationException if the {@code addAll} operation
297 * is not supported by this list
298 * @throws ClassCastException if the class of an element of the specified
299 * collection prevents it from being added to this list
300 * @throws NullPointerException if the specified collection contains one
301 * or more null elements and this list does not permit null
302 * elements, or if the specified collection is null
303 * @throws IllegalArgumentException if some property of an element of the
304 * specified collection prevents it from being added to this list
305 * @see #add(Object)
306 */
307 boolean addAll(Collection<? extends E> c);
308
309 /**
310 * Inserts all of the elements in the specified collection into this
311 * list at the specified position (optional operation). Shifts the
312 * element currently at that position (if any) and any subsequent
313 * elements to the right (increases their indices). The new elements
314 * will appear in this list in the order that they are returned by the
315 * specified collection's iterator. The behavior of this operation is
316 * undefined if the specified collection is modified while the
317 * operation is in progress. (Note that this will occur if the specified
318 * collection is this list, and it's nonempty.)
319 *
320 * @param index index at which to insert the first element from the
321 * specified collection
322 * @param c collection containing elements to be added to this list
323 * @return {@code true} if this list changed as a result of the call
324 * @throws UnsupportedOperationException if the {@code addAll} operation
325 * is not supported by this list
326 * @throws ClassCastException if the class of an element of the specified
327 * collection prevents it from being added to this list
328 * @throws NullPointerException if the specified collection contains one
329 * or more null elements and this list does not permit null
330 * elements, or if the specified collection is null
331 * @throws IllegalArgumentException if some property of an element of the
332 * specified collection prevents it from being added to this list
333 * @throws IndexOutOfBoundsException if the index is out of range
334 * ({@code index < 0 || index > size()})
335 */
336 boolean addAll(int index, Collection<? extends E> c);
337
338 /**
339 * Removes from this list all of its elements that are contained in the
340 * specified collection (optional operation).
341 *
342 * @param c collection containing elements to be removed from this list
343 * @return {@code true} if this list changed as a result of the call
344 * @throws UnsupportedOperationException if the {@code removeAll} operation
345 * is not supported by this list
346 * @throws ClassCastException if the class of an element of this list
347 * is incompatible with the specified collection
348 * (<a href="Collection.html#optional-restrictions">optional</a>)
349 * @throws NullPointerException if this list contains a null element and the
350 * specified collection does not permit null elements
351 * (<a href="Collection.html#optional-restrictions">optional</a>),
352 * or if the specified collection is null
353 * @see #remove(Object)
354 * @see #contains(Object)
355 */
356 boolean removeAll(Collection<?> c);
357
358 /**
359 * Retains only the elements in this list that are contained in the
360 * specified collection (optional operation). In other words, removes
361 * from this list all of its elements that are not contained in the
362 * specified collection.
363 *
364 * @param c collection containing elements to be retained in this list
365 * @return {@code true} if this list changed as a result of the call
366 * @throws UnsupportedOperationException if the {@code retainAll} operation
367 * is not supported by this list
368 * @throws ClassCastException if the class of an element of this list
369 * is incompatible with the specified collection
370 * (<a href="Collection.html#optional-restrictions">optional</a>)
371 * @throws NullPointerException if this list contains a null element and the
372 * specified collection does not permit null elements
373 * (<a href="Collection.html#optional-restrictions">optional</a>),
374 * or if the specified collection is null
375 * @see #remove(Object)
376 * @see #contains(Object)
377 */
378 boolean retainAll(Collection<?> c);
379
380 /**
381 * Replaces each element of this list with the result of applying the
382 * operator to that element. Errors or runtime exceptions thrown by
383 * the operator are relayed to the caller.
384 *
385 * @implSpec
386 * The default implementation is equivalent to, for this {@code list}:
387 * <pre>{@code
388 * final ListIterator<E> li = list.listIterator();
389 * while (li.hasNext()) {
390 * li.set(operator.apply(li.next()));
391 * }
392 * }</pre>
393 *
394 * If the list's list-iterator does not support the {@code set} operation
395 * then an {@code UnsupportedOperationException} will be thrown when
396 * replacing the first element.
397 *
398 * @param operator the operator to apply to each element
399 * @throws UnsupportedOperationException if this list is unmodifiable.
400 * Implementations may throw this exception if an element
401 * cannot be replaced or if, in general, modification is not
402 * supported
403 * @throws NullPointerException if the specified operator is null or
404 * if the operator result is a null value and this list does
405 * not permit null elements
406 * (<a href="Collection.html#optional-restrictions">optional</a>)
407 * @since 1.8
408 */
409 default void replaceAll(UnaryOperator<E> operator) {
410 Objects.requireNonNull(operator);
411 final ListIterator<E> li = this.listIterator();
412 while (li.hasNext()) {
413 li.set(operator.apply(li.next()));
414 }
415 }
416
417 /**
418 * Sorts this list according to the order induced by the specified
419 * {@link Comparator}.
420 *
421 * <p>All elements in this list must be <i>mutually comparable</i> using the
422 * specified comparator (that is, {@code c.compare(e1, e2)} must not throw
423 * a {@code ClassCastException} for any elements {@code e1} and {@code e2}
424 * in the list).
425 *
426 * <p>If the specified comparator is {@code null} then all elements in this
427 * list must implement the {@link Comparable} interface and the elements'
428 * {@linkplain Comparable natural ordering} should be used.
429 *
430 * <p>This list must be modifiable, but need not be resizable.
431 *
432 * @implSpec
433 * The default implementation obtains an array containing all elements in
434 * this list, sorts the array, and iterates over this list resetting each
435 * element from the corresponding position in the array. (This avoids the
436 * n<sup>2</sup> log(n) performance that would result from attempting
437 * to sort a linked list in place.)
438 *
439 * @implNote
440 * This implementation is a stable, adaptive, iterative mergesort that
441 * requires far fewer than n lg(n) comparisons when the input array is
442 * partially sorted, while offering the performance of a traditional
443 * mergesort when the input array is randomly ordered. If the input array
444 * is nearly sorted, the implementation requires approximately n
445 * comparisons. Temporary storage requirements vary from a small constant
446 * for nearly sorted input arrays to n/2 object references for randomly
447 * ordered input arrays.
448 *
449 * <p>The implementation takes equal advantage of ascending and
450 * descending order in its input array, and can take advantage of
451 * ascending and descending order in different parts of the same
452 * input array. It is well-suited to merging two or more sorted arrays:
453 * simply concatenate the arrays and sort the resulting array.
454 *
455 * <p>The implementation was adapted from Tim Peters's list sort for Python
456 * (<a href="http://svn.python.org/projects/python/trunk/Objects/listsort.txt">
457 * TimSort</a>). It uses techniques from Peter McIlroy's "Optimistic
458 * Sorting and Information Theoretic Complexity", in Proceedings of the
459 * Fourth Annual ACM-SIAM Symposium on Discrete Algorithms, pp 467-474,
460 * January 1993.
461 *
462 * @param c the {@code Comparator} used to compare list elements.
463 * A {@code null} value indicates that the elements'
464 * {@linkplain Comparable natural ordering} should be used
465 * @throws ClassCastException if the list contains elements that are not
466 * <i>mutually comparable</i> using the specified comparator
467 * @throws UnsupportedOperationException if the list's list-iterator does
468 * not support the {@code set} operation
469 * @throws IllegalArgumentException
470 * (<a href="Collection.html#optional-restrictions">optional</a>)
471 * if the comparator is found to violate the {@link Comparator}
472 * contract
473 * @since 1.8
474 */
475 @SuppressWarnings({"unchecked", "rawtypes"})
476 default void sort(Comparator<? super E> c) {
477 Object[] a = this.toArray();
478 Arrays.sort(a, (Comparator) c);
479 ListIterator<E> i = this.listIterator();
480 for (Object e : a) {
481 i.next();
482 i.set((E) e);
483 }
484 }
485
486 /**
487 * Removes all of the elements from this list (optional operation).
488 * The list will be empty after this call returns.
489 *
490 * @throws UnsupportedOperationException if the {@code clear} operation
491 * is not supported by this list
492 */
493 void clear();
494
495
496 // Comparison and hashing
497
498 /**
499 * Compares the specified object with this list for equality. Returns
500 * {@code true} if and only if the specified object is also a list, both
501 * lists have the same size, and all corresponding pairs of elements in
502 * the two lists are <i>equal</i>. (Two elements {@code e1} and
503 * {@code e2} are <i>equal</i> if {@code Objects.equals(e1, e2)}.)
504 * In other words, two lists are defined to be
505 * equal if they contain the same elements in the same order. This
506 * definition ensures that the equals method works properly across
507 * different implementations of the {@code List} interface.
508 *
509 * @param o the object to be compared for equality with this list
510 * @return {@code true} if the specified object is equal to this list
511 */
512 boolean equals(Object o);
513
514 /**
515 * Returns the hash code value for this list. The hash code of a list
516 * is defined to be the result of the following calculation:
517 * <pre>{@code
518 * int hashCode = 1;
519 * for (E e : list)
520 * hashCode = 31*hashCode + (e==null ? 0 : e.hashCode());
521 * }</pre>
522 * This ensures that {@code list1.equals(list2)} implies that
523 * {@code list1.hashCode()==list2.hashCode()} for any two lists,
524 * {@code list1} and {@code list2}, as required by the general
525 * contract of {@link Object#hashCode}.
526 *
527 * @return the hash code value for this list
528 * @see Object#equals(Object)
529 * @see #equals(Object)
530 */
531 int hashCode();
532
533
534 // Positional Access Operations
535
536 /**
537 * Returns the element at the specified position in this list.
538 *
539 * @param index index of the element to return
540 * @return the element at the specified position in this list
541 * @throws IndexOutOfBoundsException if the index is out of range
542 * ({@code index < 0 || index >= size()})
543 */
544 E get(int index);
545
546 /**
547 * Replaces the element at the specified position in this list with the
548 * specified element (optional operation).
549 *
550 * @param index index of the element to replace
551 * @param element element to be stored at the specified position
552 * @return the element previously at the specified position
553 * @throws UnsupportedOperationException if the {@code set} operation
554 * is not supported by this list
555 * @throws ClassCastException if the class of the specified element
556 * prevents it from being added to this list
557 * @throws NullPointerException if the specified element is null and
558 * this list does not permit null elements
559 * @throws IllegalArgumentException if some property of the specified
560 * element prevents it from being added to this list
561 * @throws IndexOutOfBoundsException if the index is out of range
562 * ({@code index < 0 || index >= size()})
563 */
564 E set(int index, E element);
565
566 /**
567 * Inserts the specified element at the specified position in this list
568 * (optional operation). Shifts the element currently at that position
569 * (if any) and any subsequent elements to the right (adds one to their
570 * indices).
571 *
572 * @param index index at which the specified element is to be inserted
573 * @param element element to be inserted
574 * @throws UnsupportedOperationException if the {@code add} operation
575 * is not supported by this list
576 * @throws ClassCastException if the class of the specified element
577 * prevents it from being added to this list
578 * @throws NullPointerException if the specified element is null and
579 * this list does not permit null elements
580 * @throws IllegalArgumentException if some property of the specified
581 * element prevents it from being added to this list
582 * @throws IndexOutOfBoundsException if the index is out of range
583 * ({@code index < 0 || index > size()})
584 */
585 void add(int index, E element);
586
587 /**
588 * Removes the element at the specified position in this list (optional
589 * operation). Shifts any subsequent elements to the left (subtracts one
590 * from their indices). Returns the element that was removed from the
591 * list.
592 *
593 * @param index the index of the element to be removed
594 * @return the element previously at the specified position
595 * @throws UnsupportedOperationException if the {@code remove} operation
596 * is not supported by this list
597 * @throws IndexOutOfBoundsException if the index is out of range
598 * ({@code index < 0 || index >= size()})
599 */
600 E remove(int index);
601
602
603 // Search Operations
604
605 /**
606 * Returns the index of the first occurrence of the specified element
607 * in this list, or -1 if this list does not contain the element.
608 * More formally, returns the lowest index {@code i} such that
609 * {@code Objects.equals(o, get(i))},
610 * or -1 if there is no such index.
611 *
612 * @param o element to search for
613 * @return the index of the first occurrence of the specified element in
614 * this list, or -1 if this list does not contain the element
615 * @throws ClassCastException if the type of the specified element
616 * is incompatible with this list
617 * (<a href="Collection.html#optional-restrictions">optional</a>)
618 * @throws NullPointerException if the specified element is null and this
619 * list does not permit null elements
620 * (<a href="Collection.html#optional-restrictions">optional</a>)
621 */
622 int indexOf(Object o);
623
624 /**
625 * Returns the index of the last occurrence of the specified element
626 * in this list, or -1 if this list does not contain the element.
627 * More formally, returns the highest index {@code i} such that
628 * {@code Objects.equals(o, get(i))},
629 * or -1 if there is no such index.
630 *
631 * @param o element to search for
632 * @return the index of the last occurrence of the specified element in
633 * this list, or -1 if this list does not contain the element
634 * @throws ClassCastException if the type of the specified element
635 * is incompatible with this list
636 * (<a href="Collection.html#optional-restrictions">optional</a>)
637 * @throws NullPointerException if the specified element is null and this
638 * list does not permit null elements
639 * (<a href="Collection.html#optional-restrictions">optional</a>)
640 */
641 int lastIndexOf(Object o);
642
643
644 // List Iterators
645
646 /**
647 * Returns a list iterator over the elements in this list (in proper
648 * sequence).
649 *
650 * @return a list iterator over the elements in this list (in proper
651 * sequence)
652 */
653 ListIterator<E> listIterator();
654
655 /**
656 * Returns a list iterator over the elements in this list (in proper
657 * sequence), starting at the specified position in the list.
658 * The specified index indicates the first element that would be
659 * returned by an initial call to {@link ListIterator#next next}.
660 * An initial call to {@link ListIterator#previous previous} would
661 * return the element with the specified index minus one.
662 *
663 * @param index index of the first element to be returned from the
664 * list iterator (by a call to {@link ListIterator#next next})
665 * @return a list iterator over the elements in this list (in proper
666 * sequence), starting at the specified position in the list
667 * @throws IndexOutOfBoundsException if the index is out of range
668 * ({@code index < 0 || index > size()})
669 */
670 ListIterator<E> listIterator(int index);
671
672 // View
673
674 /**
675 * Returns a view of the portion of this list between the specified
676 * {@code fromIndex}, inclusive, and {@code toIndex}, exclusive. (If
677 * {@code fromIndex} and {@code toIndex} are equal, the returned list is
678 * empty.) The returned list is backed by this list, so non-structural
679 * changes in the returned list are reflected in this list, and vice-versa.
680 * The returned list supports all of the optional list operations supported
681 * by this list.<p>
682 *
683 * This method eliminates the need for explicit range operations (of
684 * the sort that commonly exist for arrays). Any operation that expects
685 * a list can be used as a range operation by passing a subList view
686 * instead of a whole list. For example, the following idiom
687 * removes a range of elements from a list:
688 * <pre>{@code
689 * list.subList(from, to).clear();
690 * }</pre>
691 * Similar idioms may be constructed for {@code indexOf} and
692 * {@code lastIndexOf}, and all of the algorithms in the
693 * {@code Collections} class can be applied to a subList.<p>
694 *
695 * The semantics of the list returned by this method become undefined if
696 * the backing list (i.e., this list) is <i>structurally modified</i> in
697 * any way other than via the returned list. (Structural modifications are
698 * those that change the size of this list, or otherwise perturb it in such
699 * a fashion that iterations in progress may yield incorrect results.)
700 *
701 * @param fromIndex low endpoint (inclusive) of the subList
702 * @param toIndex high endpoint (exclusive) of the subList
703 * @return a view of the specified range within this list
704 * @throws IndexOutOfBoundsException for an illegal endpoint index value
705 * ({@code fromIndex < 0 || toIndex > size ||
706 * fromIndex > toIndex})
707 */
708 List<E> subList(int fromIndex, int toIndex);
709
710 /**
711 * Creates a {@link Spliterator} over the elements in this list.
712 *
713 * <p>The {@code Spliterator} reports {@link Spliterator#SIZED} and
714 * {@link Spliterator#ORDERED}. Implementations should document the
715 * reporting of additional characteristic values.
716 *
717 * @implSpec
718 * The default implementation creates a
719 * <em><a href="Spliterator.html#binding">late-binding</a></em> spliterator
720 * from the list's {@code Iterator}. The spliterator inherits the
721 * <em>fail-fast</em> properties of the list's iterator.
722 *
723 * @implNote
724 * The created {@code Spliterator} additionally reports
725 * {@link Spliterator#SUBSIZED}.
726 *
727 * @return a {@code Spliterator} over the elements in this list
728 * @since 1.8
729 */
730 @Override
731 default Spliterator<E> spliterator() {
732 return Spliterators.spliterator(this, Spliterator.ORDERED);
733 }
734 }