| /* | |
| * Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved. | |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
| * | |
| * This code is free software; you can redistribute it and/or modify it | |
| * under the terms of the GNU General Public License version 2 only, as | |
| * published by the Free Software Foundation. Oracle designates this | |
| * particular file as subject to the "Classpath" exception as provided | |
| * by Oracle in the LICENSE file that accompanied this code. | |
| * | |
| * This code is distributed in the hope that it will be useful, but WITHOUT | |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| * version 2 for more details (a copy is included in the LICENSE file that | |
| * accompanied this code). | |
| * | |
| * You should have received a copy of the GNU General Public License version | |
| * 2 along with this work; if not, write to the Free Software Foundation, | |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| * | |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| * or visit www.oracle.com if you need additional information or have any | |
| * questions. | |
| */ | |
| package java.util; | |
| import java.util.function.UnaryOperator; | |
| /** | |
| * An ordered collection, where the user has precise control over where in the | |
| * list each element is inserted. The user can access elements by their integer | |
| * index (position in the list), and search for elements in the list.<p> | |
| * | |
| * Unlike sets, lists typically allow duplicate elements. More formally, | |
| * lists typically allow pairs of elements {@code e1} and {@code e2} | |
| * such that {@code e1.equals(e2)}, and they typically allow multiple | |
| * null elements if they allow null elements at all. It is not inconceivable | |
| * that someone might wish to implement a list that prohibits duplicates, by | |
| * throwing runtime exceptions when the user attempts to insert them, but we | |
| * expect this usage to be rare.<p> | |
| * | |
| * The {@code List} interface places additional stipulations, beyond those | |
| * specified in the {@code Collection} interface, on the contracts of the | |
| * {@code iterator}, {@code add}, {@code remove}, {@code equals}, and | |
| * {@code hashCode} methods. Declarations for other inherited methods are | |
| * also included here for convenience.<p> | |
| * | |
| * The {@code List} interface provides four methods for positional (indexed) | |
| * access to list elements. Lists (like Java arrays) are zero based. Note | |
| * that these operations may execute in time proportional to the index value | |
| * for some implementations (the {@code LinkedList} class, for | |
| * example). Thus, iterating over the elements in a list is typically | |
| * preferable to indexing through it if the caller does not know the | |
| * implementation.<p> | |
| * | |
| * The {@code List} interface provides a special iterator, called a | |
| * {@code ListIterator}, that allows element insertion and replacement, and | |
| * bidirectional access in addition to the normal operations that the | |
| * {@code Iterator} interface provides. A method is provided to obtain a | |
| * list iterator that starts at a specified position in the list.<p> | |
| * | |
| * The {@code List} interface provides two methods to search for a specified | |
| * object. From a performance standpoint, these methods should be used with | |
| * caution. In many implementations they will perform costly linear | |
| * searches.<p> | |
| * | |
| * The {@code List} interface provides two methods to efficiently insert and | |
| * remove multiple elements at an arbitrary point in the list.<p> | |
| * | |
| * Note: While it is permissible for lists to contain themselves as elements, | |
| * extreme caution is advised: the {@code equals} and {@code hashCode} | |
| * methods are no longer well defined on such a list. | |
| * | |
| * <p>Some list implementations have restrictions on the elements that | |
| * they may contain. For example, some implementations prohibit null elements, | |
| * and some have restrictions on the types of their elements. Attempting to | |
| * add an ineligible element throws an unchecked exception, typically | |
| * {@code NullPointerException} or {@code ClassCastException}. Attempting | |
| * to query the presence of an ineligible element may throw an exception, | |
| * or it may simply return false; some implementations will exhibit the former | |
| * behavior and some will exhibit the latter. More generally, attempting an | |
| * operation on an ineligible element whose completion would not result in | |
| * the insertion of an ineligible element into the list may throw an | |
| * exception or it may succeed, at the option of the implementation. | |
| * Such exceptions are marked as "optional" in the specification for this | |
| * interface. | |
| * | |
| * <h2><a id="unmodifiable">Unmodifiable Lists</a></h2> | |
| * <p>The {@link List#of(Object...) List.of} and | |
| * {@link List#copyOf List.copyOf} static factory methods | |
| * provide a convenient way to create unmodifiable lists. The {@code List} | |
| * instances created by these methods have the following characteristics: | |
| * | |
| * <ul> | |
| * <li>They are <a href="Collection.html#unmodifiable"><i>unmodifiable</i></a>. Elements cannot | |
| * be added, removed, or replaced. Calling any mutator method on the List | |
| * will always cause {@code UnsupportedOperationException} to be thrown. | |
| * However, if the contained elements are themselves mutable, | |
| * this may cause the List's contents to appear to change. | |
| * <li>They disallow {@code null} elements. Attempts to create them with | |
| * {@code null} elements result in {@code NullPointerException}. | |
| * <li>They are serializable if all elements are serializable. | |
| * <li>The order of elements in the list is the same as the order of the | |
| * provided arguments, or of the elements in the provided array. | |
| * <li>The lists and their {@link #subList(int, int) subList} views implement the | |
| * {@link RandomAccess} interface. | |
| * <li>They are <a href="../lang/doc-files/ValueBased.html">value-based</a>. | |
| * Programmers should treat instances that are {@linkplain #equals(Object) equal} | |
| * as interchangeable and should not use them for synchronization, or | |
| * unpredictable behavior may occur. For example, in a future release, | |
| * synchronization may fail. Callers should make no assumptions about the | |
| * identity of the returned instances. Factories are free to | |
| * create new instances or reuse existing ones. | |
| * <li>They are serialized as specified on the | |
| * <a href="{@docRoot}/serialized-form.html#java.util.CollSer">Serialized Form</a> | |
| * page. | |
| * </ul> | |
| * | |
| * <p>This interface is a member of the | |
| * <a href="{@docRoot}/java.base/java/util/package-summary.html#CollectionsFramework"> | |
| * Java Collections Framework</a>. | |
| * | |
| * @param <E> the type of elements in this list | |
| * | |
| * @author Josh Bloch | |
| * @author Neal Gafter | |
| * @see Collection | |
| * @see Set | |
| * @see ArrayList | |
| * @see LinkedList | |
| * @see Vector | |
| * @see Arrays#asList(Object[]) | |
| * @see Collections#nCopies(int, Object) | |
| * @see Collections#EMPTY_LIST | |
| * @see AbstractList | |
| * @see AbstractSequentialList | |
| * @since 1.2 | |
| */ | |
| public interface List<E> extends SequencedCollection<E> { | |
| // Query Operations | |
| /** | |
| * Returns the number of elements in this list. If this list contains | |
| * more than {@code Integer.MAX_VALUE} elements, returns | |
| * {@code Integer.MAX_VALUE}. | |
| * | |
| * @return the number of elements in this list | |
| */ | |
| int size(); | |
| /** | |
| * Returns {@code true} if this list contains no elements. | |
| * | |
| * @return {@code true} if this list contains no elements | |
| */ | |
| boolean isEmpty(); | |
| /** | |
| * Returns {@code true} if this list contains the specified element. | |
| * More formally, returns {@code true} if and only if this list contains | |
| * at least one element {@code e} such that | |
| * {@code Objects.equals(o, e)}. | |
| * | |
| * @param o element whose presence in this list is to be tested | |
| * @return {@code true} if this list contains the specified element | |
| * @throws ClassCastException if the type of the specified element | |
| * is incompatible with this list | |
| * (<a href="Collection.html#optional-restrictions">optional</a>) | |
| * @throws NullPointerException if the specified element is null and this | |
| * list does not permit null elements | |
| * (<a href="Collection.html#optional-restrictions">optional</a>) | |
| */ | |
| boolean contains(Object o); | |
| /** | |
| * Returns an iterator over the elements in this list in proper sequence. | |
| * | |
| * @return an iterator over the elements in this list in proper sequence | |
| */ | |
| Iterator<E> iterator(); | |
| /** | |
| * Returns an array containing all of the elements in this list in proper | |
| * sequence (from first to last element). | |
| * | |
| * <p>The returned array will be "safe" in that no references to it are | |
| * maintained by this list. (In other words, this method must | |
| * allocate a new array even if this list is backed by an array). | |
| * The caller is thus free to modify the returned array. | |
| * | |
| * <p>This method acts as bridge between array-based and collection-based | |
| * APIs. | |
| * | |
| * @return an array containing all of the elements in this list in proper | |
| * sequence | |
| * @see Arrays#asList(Object[]) | |
| */ | |
| Object[] toArray(); | |
| /** | |
| * Returns an array containing all of the elements in this list in | |
| * proper sequence (from first to last element); the runtime type of | |
| * the returned array is that of the specified array. If the list fits | |
| * in the specified array, it is returned therein. Otherwise, a new | |
| * array is allocated with the runtime type of the specified array and | |
| * the size of this list. | |
| * | |
| * <p>If the list fits in the specified array with room to spare (i.e., | |
| * the array has more elements than the list), the element in the array | |
| * immediately following the end of the list is set to {@code null}. | |
| * (This is useful in determining the length of the list <i>only</i> if | |
| * the caller knows that the list does not contain any null elements.) | |
| * | |
| * <p>Like the {@link #toArray()} method, this method acts as bridge between | |
| * array-based and collection-based APIs. Further, this method allows | |
| * precise control over the runtime type of the output array, and may, | |
| * under certain circumstances, be used to save allocation costs. | |
| * | |
| * <p>Suppose {@code x} is a list known to contain only strings. | |
| * The following code can be used to dump the list into a newly | |
| * allocated array of {@code String}: | |
| * | |
| * <pre>{@code | |
| * String[] y = x.toArray(new String[0]); | |
| * }</pre> | |
| * | |
| * Note that {@code toArray(new Object[0])} is identical in function to | |
| * {@code toArray()}. | |
| * | |
| * @param a the array into which the elements of this list are to | |
| * be stored, if it is big enough; otherwise, a new array of the | |
| * same runtime type is allocated for this purpose. | |
| * @return an array containing the elements of this list | |
| * @throws ArrayStoreException if the runtime type of the specified array | |
| * is not a supertype of the runtime type of every element in | |
| * this list | |
| * @throws NullPointerException if the specified array is null | |
| */ | |
| <T> T[] toArray(T[] a); | |
| // Modification Operations | |
| /** | |
| * Appends the specified element to the end of this list (optional | |
| * operation). | |
| * | |
| * <p>Lists that support this operation may place limitations on what | |
| * elements may be added to this list. In particular, some | |
| * lists will refuse to add null elements, and others will impose | |
| * restrictions on the type of elements that may be added. List | |
| * classes should clearly specify in their documentation any restrictions | |
| * on what elements may be added. | |
| * | |
| * @param e element to be appended to this list | |
| * @return {@code true} (as specified by {@link Collection#add}) | |
| * @throws UnsupportedOperationException if the {@code add} operation | |
| * is not supported by this list | |
| * @throws ClassCastException if the class of the specified element | |
| * prevents it from being added to this list | |
| * @throws NullPointerException if the specified element is null and this | |
| * list does not permit null elements | |
| * @throws IllegalArgumentException if some property of this element | |
| * prevents it from being added to this list | |
| */ | |
| boolean add(E e); | |
| /** | |
| * Removes the first occurrence of the specified element from this list, | |
| * if it is present (optional operation). If this list does not contain | |
| * the element, it is unchanged. More formally, removes the element with | |
| * the lowest index {@code i} such that | |
| * {@code Objects.equals(o, get(i))} | |
| * (if such an element exists). Returns {@code true} if this list | |
| * contained the specified element (or equivalently, if this list changed | |
| * as a result of the call). | |
| * | |
| * @param o element to be removed from this list, if present | |
| * @return {@code true} if this list contained the specified element | |
| * @throws ClassCastException if the type of the specified element | |
| * is incompatible with this list | |
| * (<a href="Collection.html#optional-restrictions">optional</a>) | |
| * @throws NullPointerException if the specified element is null and this | |
| * list does not permit null elements | |
| * (<a href="Collection.html#optional-restrictions">optional</a>) | |
| * @throws UnsupportedOperationException if the {@code remove} operation | |
| * is not supported by this list | |
| */ | |
| boolean remove(Object o); | |
| // Bulk Modification Operations | |
| /** | |
| * Returns {@code true} if this list contains all of the elements of the | |
| * specified collection. | |
| * | |
| * @param c collection to be checked for containment in this list | |
| * @return {@code true} if this list contains all of the elements of the | |
| * specified collection | |
| * @throws ClassCastException if the types of one or more elements | |
| * in the specified collection are incompatible with this | |
| * list | |
| * (<a href="Collection.html#optional-restrictions">optional</a>) | |
| * @throws NullPointerException if the specified collection contains one | |
| * or more null elements and this list does not permit null | |
| * elements | |
| * (<a href="Collection.html#optional-restrictions">optional</a>), | |
| * or if the specified collection is null | |
| * @see #contains(Object) | |
| */ | |
| boolean containsAll(Collection<?> c); | |
| /** | |
| * Appends all of the elements in the specified collection to the end of | |
| * this list, in the order that they are returned by the specified | |
| * collection's iterator (optional operation). The behavior of this | |
| * operation is undefined if the specified collection is modified while | |
| * the operation is in progress. (Note that this will occur if the | |
| * specified collection is this list, and it's nonempty.) | |
| * | |
| * @param c collection containing elements to be added to this list | |
| * @return {@code true} if this list changed as a result of the call | |
| * @throws UnsupportedOperationException if the {@code addAll} operation | |
| * is not supported by this list | |
| * @throws ClassCastException if the class of an element of the specified | |
| * collection prevents it from being added to this list | |
| * @throws NullPointerException if the specified collection contains one | |
| * or more null elements and this list does not permit null | |
| * elements, or if the specified collection is null | |
| * @throws IllegalArgumentException if some property of an element of the | |
| * specified collection prevents it from being added to this list | |
| * @see #add(Object) | |
| */ | |
| boolean addAll(Collection<? extends E> c); | |
| /** | |
| * Inserts all of the elements in the specified collection into this | |
| * list at the specified position (optional operation). Shifts the | |
| * element currently at that position (if any) and any subsequent | |
| * elements to the right (increases their indices). The new elements | |
| * will appear in this list in the order that they are returned by the | |
| * specified collection's iterator. The behavior of this operation is | |
| * undefined if the specified collection is modified while the | |
| * operation is in progress. (Note that this will occur if the specified | |
| * collection is this list, and it's nonempty.) | |
| * | |
| * @param index index at which to insert the first element from the | |
| * specified collection | |
| * @param c collection containing elements to be added to this list | |
| * @return {@code true} if this list changed as a result of the call | |
| * @throws UnsupportedOperationException if the {@code addAll} operation | |
| * is not supported by this list | |
| * @throws ClassCastException if the class of an element of the specified | |
| * collection prevents it from being added to this list | |
| * @throws NullPointerException if the specified collection contains one | |
| * or more null elements and this list does not permit null | |
| * elements, or if the specified collection is null | |
| * @throws IllegalArgumentException if some property of an element of the | |
| * specified collection prevents it from being added to this list | |
| * @throws IndexOutOfBoundsException if the index is out of range | |
| * ({@code index < 0 || index > size()}) | |
| */ | |
| boolean addAll(int index, Collection<? extends E> c); | |
| /** | |
| * Removes from this list all of its elements that are contained in the | |
| * specified collection (optional operation). | |
| * | |
| * @param c collection containing elements to be removed from this list | |
| * @return {@code true} if this list changed as a result of the call | |
| * @throws UnsupportedOperationException if the {@code removeAll} operation | |
| * is not supported by this list | |
| * @throws ClassCastException if the class of an element of this list | |
| * is incompatible with the specified collection | |
| * (<a href="Collection.html#optional-restrictions">optional</a>) | |
| * @throws NullPointerException if this list contains a null element and the | |
| * specified collection does not permit null elements | |
| * (<a href="Collection.html#optional-restrictions">optional</a>), | |
| * or if the specified collection is null | |
| * @see #remove(Object) | |
| * @see #contains(Object) | |
| */ | |
| boolean removeAll(Collection<?> c); | |
| /** | |
| * Retains only the elements in this list that are contained in the | |
| * specified collection (optional operation). In other words, removes | |
| * from this list all of its elements that are not contained in the | |
| * specified collection. | |
| * | |
| * @param c collection containing elements to be retained in this list | |
| * @return {@code true} if this list changed as a result of the call | |
| * @throws UnsupportedOperationException if the {@code retainAll} operation | |
| * is not supported by this list | |
| * @throws ClassCastException if the class of an element of this list | |
| * is incompatible with the specified collection | |
| * (<a href="Collection.html#optional-restrictions">optional</a>) | |
| * @throws NullPointerException if this list contains a null element and the | |
| * specified collection does not permit null elements | |
| * (<a href="Collection.html#optional-restrictions">optional</a>), | |
| * or if the specified collection is null | |
| * @see #remove(Object) | |
| * @see #contains(Object) | |
| */ | |
| boolean retainAll(Collection<?> c); | |
| /** | |
| * Replaces each element of this list with the result of applying the | |
| * operator to that element (optional operation). Errors or runtime | |
| * exceptions thrown by the operator are relayed to the caller. | |
| * | |
| * @implSpec | |
| * The default implementation is equivalent to, for this {@code list}: | |
| * <pre>{@code | |
| * final ListIterator<E> li = list.listIterator(); | |
| * while (li.hasNext()) { | |
| * li.set(operator.apply(li.next())); | |
| * } | |
| * }</pre> | |
| * | |
| * If the list's list-iterator does not support the {@code set} operation | |
| * then an {@code UnsupportedOperationException} will be thrown when | |
| * replacing the first element. | |
| * | |
| * @param operator the operator to apply to each element | |
| * @throws UnsupportedOperationException if the {@code replaceAll} operation | |
| * is not supported by this list | |
| * @throws NullPointerException if the specified operator is null or | |
| * if the operator result is a null value and this list does | |
| * not permit null elements | |
| * (<a href="Collection.html#optional-restrictions">optional</a>) | |
| * @since 1.8 | |
| */ | |
| default void replaceAll(UnaryOperator<E> operator) { | |
| Objects.requireNonNull(operator); | |
| final ListIterator<E> li = this.listIterator(); | |
| while (li.hasNext()) { | |
| li.set(operator.apply(li.next())); | |
| } | |
| } | |
| /** | |
| * Sorts this list according to the order induced by the specified | |
| * {@link Comparator} (optional operation). The sort is <i>stable</i>: | |
| * this method must not reorder equal elements. | |
| * | |
| * <p>All elements in this list must be <i>mutually comparable</i> using the | |
| * specified comparator (that is, {@code c.compare(e1, e2)} must not throw | |
| * a {@code ClassCastException} for any elements {@code e1} and {@code e2} | |
| * in the list). | |
| * | |
| * <p>If the specified comparator is {@code null} then all elements in this | |
| * list must implement the {@link Comparable} interface and the elements' | |
| * {@linkplain Comparable natural ordering} should be used. | |
| * | |
| * <p>This list must be modifiable, but need not be resizable. | |
| * | |
| * @implSpec | |
| * The default implementation obtains an array containing all elements in | |
| * this list, sorts the array, and iterates over this list resetting each | |
| * element from the corresponding position in the array. (This avoids the | |
| * n<sup>2</sup> log(n) performance that would result from attempting | |
| * to sort a linked list in place.) | |
| * | |
| * @implNote | |
| * This implementation is a stable, adaptive, iterative mergesort that | |
| * requires far fewer than n lg(n) comparisons when the input array is | |
| * partially sorted, while offering the performance of a traditional | |
| * mergesort when the input array is randomly ordered. If the input array | |
| * is nearly sorted, the implementation requires approximately n | |
| * comparisons. Temporary storage requirements vary from a small constant | |
| * for nearly sorted input arrays to n/2 object references for randomly | |
| * ordered input arrays. | |
| * | |
| * <p>The implementation takes equal advantage of ascending and | |
| * descending order in its input array, and can take advantage of | |
| * ascending and descending order in different parts of the same | |
| * input array. It is well-suited to merging two or more sorted arrays: | |
| * simply concatenate the arrays and sort the resulting array. | |
| * | |
| * <p>The implementation was adapted from Tim Peters's list sort for Python | |
| * (<a href="http://svn.python.org/projects/python/trunk/Objects/listsort.txt"> | |
| * TimSort</a>). It uses techniques from Peter McIlroy's "Optimistic | |
| * Sorting and Information Theoretic Complexity", in Proceedings of the | |
| * Fourth Annual ACM-SIAM Symposium on Discrete Algorithms, pp 467-474, | |
| * January 1993. | |
| * | |
| * @param c the {@code Comparator} used to compare list elements. | |
| * A {@code null} value indicates that the elements' | |
| * {@linkplain Comparable natural ordering} should be used | |
| * @throws ClassCastException if the list contains elements that are not | |
| * <i>mutually comparable</i> using the specified comparator | |
| * @throws UnsupportedOperationException if the {@code sort} operation | |
| * is not supported by this list | |
| * @throws IllegalArgumentException | |
| * (<a href="Collection.html#optional-restrictions">optional</a>) | |
| * if the comparator is found to violate the {@link Comparator} | |
| * contract | |
| * @since 1.8 | |
| */ | |
| @SuppressWarnings("unchecked") | |
| default void sort(Comparator<? super E> c) { | |
| Object[] a = this.toArray(); | |
| Arrays.sort(a, (Comparator) c); | |
| ListIterator<E> i = this.listIterator(); | |
| for (Object e : a) { | |
| i.next(); | |
| i.set((E) e); | |
| } | |
| } | |
| /** | |
| * Removes all of the elements from this list (optional operation). | |
| * The list will be empty after this call returns. | |
| * | |
| * @throws UnsupportedOperationException if the {@code clear} operation | |
| * is not supported by this list | |
| */ | |
| void clear(); | |
| // Comparison and hashing | |
| /** | |
| * Compares the specified object with this list for equality. Returns | |
| * {@code true} if and only if the specified object is also a list, both | |
| * lists have the same size, and all corresponding pairs of elements in | |
| * the two lists are <i>equal</i>. (Two elements {@code e1} and | |
| * {@code e2} are <i>equal</i> if {@code Objects.equals(e1, e2)}.) | |
| * In other words, two lists are defined to be | |
| * equal if they contain the same elements in the same order. This | |
| * definition ensures that the equals method works properly across | |
| * different implementations of the {@code List} interface. | |
| * | |
| * @param o the object to be compared for equality with this list | |
| * @return {@code true} if the specified object is equal to this list | |
| */ | |
| boolean equals(Object o); | |
| /** | |
| * Returns the hash code value for this list. The hash code of a list | |
| * is defined to be the result of the following calculation: | |
| * <pre>{@code | |
| * int hashCode = 1; | |
| * for (E e : list) | |
| * hashCode = 31*hashCode + (e==null ? 0 : e.hashCode()); | |
| * }</pre> | |
| * This ensures that {@code list1.equals(list2)} implies that | |
| * {@code list1.hashCode()==list2.hashCode()} for any two lists, | |
| * {@code list1} and {@code list2}, as required by the general | |
| * contract of {@link Object#hashCode}. | |
| * | |
| * @return the hash code value for this list | |
| * @see Object#equals(Object) | |
| * @see #equals(Object) | |
| */ | |
| int hashCode(); | |
| // Positional Access Operations | |
| /** | |
| * Returns the element at the specified position in this list. | |
| * | |
| * @param index index of the element to return | |
| * @return the element at the specified position in this list | |
| * @throws IndexOutOfBoundsException if the index is out of range | |
| * ({@code index < 0 || index >= size()}) | |
| */ | |
| E get(int index); | |
| /** | |
| * Replaces the element at the specified position in this list with the | |
| * specified element (optional operation). | |
| * | |
| * @param index index of the element to replace | |
| * @param element element to be stored at the specified position | |
| * @return the element previously at the specified position | |
| * @throws UnsupportedOperationException if the {@code set} operation | |
| * is not supported by this list | |
| * @throws ClassCastException if the class of the specified element | |
| * prevents it from being added to this list | |
| * @throws NullPointerException if the specified element is null and | |
| * this list does not permit null elements | |
| * @throws IllegalArgumentException if some property of the specified | |
| * element prevents it from being added to this list | |
| * @throws IndexOutOfBoundsException if the index is out of range | |
| * ({@code index < 0 || index >= size()}) | |
| */ | |
| E set(int index, E element); | |
| /** | |
| * Inserts the specified element at the specified position in this list | |
| * (optional operation). Shifts the element currently at that position | |
| * (if any) and any subsequent elements to the right (adds one to their | |
| * indices). | |
| * | |
| * @param index index at which the specified element is to be inserted | |
| * @param element element to be inserted | |
| * @throws UnsupportedOperationException if the {@code add} operation | |
| * is not supported by this list | |
| * @throws ClassCastException if the class of the specified element | |
| * prevents it from being added to this list | |
| * @throws NullPointerException if the specified element is null and | |
| * this list does not permit null elements | |
| * @throws IllegalArgumentException if some property of the specified | |
| * element prevents it from being added to this list | |
| * @throws IndexOutOfBoundsException if the index is out of range | |
| * ({@code index < 0 || index > size()}) | |
| */ | |
| void add(int index, E element); | |
| /** | |
| * Removes the element at the specified position in this list (optional | |
| * operation). Shifts any subsequent elements to the left (subtracts one | |
| * from their indices). Returns the element that was removed from the | |
| * list. | |
| * | |
| * @param index the index of the element to be removed | |
| * @return the element previously at the specified position | |
| * @throws UnsupportedOperationException if the {@code remove} operation | |
| * is not supported by this list | |
| * @throws IndexOutOfBoundsException if the index is out of range | |
| * ({@code index < 0 || index >= size()}) | |
| */ | |
| E remove(int index); | |
| // Search Operations | |
| /** | |
| * Returns the index of the first occurrence of the specified element | |
| * in this list, or -1 if this list does not contain the element. | |
| * More formally, returns the lowest index {@code i} such that | |
| * {@code Objects.equals(o, get(i))}, | |
| * or -1 if there is no such index. | |
| * | |
| * @param o element to search for | |
| * @return the index of the first occurrence of the specified element in | |
| * this list, or -1 if this list does not contain the element | |
| * @throws ClassCastException if the type of the specified element | |
| * is incompatible with this list | |
| * (<a href="Collection.html#optional-restrictions">optional</a>) | |
| * @throws NullPointerException if the specified element is null and this | |
| * list does not permit null elements | |
| * (<a href="Collection.html#optional-restrictions">optional</a>) | |
| */ | |
| int indexOf(Object o); | |
| /** | |
| * Returns the index of the last occurrence of the specified element | |
| * in this list, or -1 if this list does not contain the element. | |
| * More formally, returns the highest index {@code i} such that | |
| * {@code Objects.equals(o, get(i))}, | |
| * or -1 if there is no such index. | |
| * | |
| * @param o element to search for | |
| * @return the index of the last occurrence of the specified element in | |
| * this list, or -1 if this list does not contain the element | |
| * @throws ClassCastException if the type of the specified element | |
| * is incompatible with this list | |
| * (<a href="Collection.html#optional-restrictions">optional</a>) | |
| * @throws NullPointerException if the specified element is null and this | |
| * list does not permit null elements | |
| * (<a href="Collection.html#optional-restrictions">optional</a>) | |
| */ | |
| int lastIndexOf(Object o); | |
| // List Iterators | |
| /** | |
| * Returns a list iterator over the elements in this list (in proper | |
| * sequence). | |
| * | |
| * @return a list iterator over the elements in this list (in proper | |
| * sequence) | |
| */ | |
| ListIterator<E> listIterator(); | |
| /** | |
| * Returns a list iterator over the elements in this list (in proper | |
| * sequence), starting at the specified position in the list. | |
| * The specified index indicates the first element that would be | |
| * returned by an initial call to {@link ListIterator#next next}. | |
| * An initial call to {@link ListIterator#previous previous} would | |
| * return the element with the specified index minus one. | |
| * | |
| * @param index index of the first element to be returned from the | |
| * list iterator (by a call to {@link ListIterator#next next}) | |
| * @return a list iterator over the elements in this list (in proper | |
| * sequence), starting at the specified position in the list | |
| * @throws IndexOutOfBoundsException if the index is out of range | |
| * ({@code index < 0 || index > size()}) | |
| */ | |
| ListIterator<E> listIterator(int index); | |
| // View | |
| /** | |
| * Returns a view of the portion of this list between the specified | |
| * {@code fromIndex}, inclusive, and {@code toIndex}, exclusive. (If | |
| * {@code fromIndex} and {@code toIndex} are equal, the returned list is | |
| * empty.) The returned list is backed by this list, so non-structural | |
| * changes in the returned list are reflected in this list, and vice-versa. | |
| * The returned list supports all of the optional list operations supported | |
| * by this list.<p> | |
| * | |
| * This method eliminates the need for explicit range operations (of | |
| * the sort that commonly exist for arrays). Any operation that expects | |
| * a list can be used as a range operation by passing a subList view | |
| * instead of a whole list. For example, the following idiom | |
| * removes a range of elements from a list: | |
| * <pre>{@code | |
| * list.subList(from, to).clear(); | |
| * }</pre> | |
| * Similar idioms may be constructed for {@code indexOf} and | |
| * {@code lastIndexOf}, and all of the algorithms in the | |
| * {@code Collections} class can be applied to a subList.<p> | |
| * | |
| * The semantics of the list returned by this method become undefined if | |
| * the backing list (i.e., this list) is <i>structurally modified</i> in | |
| * any way other than via the returned list. (Structural modifications are | |
| * those that change the size of this list, or otherwise perturb it in such | |
| * a fashion that iterations in progress may yield incorrect results.) | |
| * | |
| * @param fromIndex low endpoint (inclusive) of the subList | |
| * @param toIndex high endpoint (exclusive) of the subList | |
| * @return a view of the specified range within this list | |
| * @throws IndexOutOfBoundsException for an illegal endpoint index value | |
| * ({@code fromIndex < 0 || toIndex > size || | |
| * fromIndex > toIndex}) | |
| */ | |
| List<E> subList(int fromIndex, int toIndex); | |
| /** | |
| * Creates a {@link Spliterator} over the elements in this list. | |
| * | |
| * <p>The {@code Spliterator} reports {@link Spliterator#SIZED} and | |
| * {@link Spliterator#ORDERED}. Implementations should document the | |
| * reporting of additional characteristic values. | |
| * | |
| * @implSpec | |
| * The default implementation creates a | |
| * <em><a href="Spliterator.html#binding">late-binding</a></em> | |
| * spliterator as follows: | |
| * <ul> | |
| * <li>If the list is an instance of {@link RandomAccess} then the default | |
| * implementation creates a spliterator that traverses elements by | |
| * invoking the method {@link List#get}. If such invocation results or | |
| * would result in an {@code IndexOutOfBoundsException} then the | |
| * spliterator will <em>fail-fast</em> and throw a | |
| * {@code ConcurrentModificationException}. | |
| * If the list is also an instance of {@link AbstractList} then the | |
| * spliterator will use the list's {@link AbstractList#modCount modCount} | |
| * field to provide additional <em>fail-fast</em> behavior. | |
| * <li>Otherwise, the default implementation creates a spliterator from the | |
| * list's {@code Iterator}. The spliterator inherits the | |
| * <em>fail-fast</em> of the list's iterator. | |
| * </ul> | |
| * | |
| * @implNote | |
| * The created {@code Spliterator} additionally reports | |
| * {@link Spliterator#SUBSIZED}. | |
| * | |
| * @return a {@code Spliterator} over the elements in this list | |
| * @since 1.8 | |
| */ | |
| @Override | |
| default Spliterator<E> spliterator() { | |
| if (this instanceof RandomAccess) { | |
| return new AbstractList.RandomAccessSpliterator<>(this); | |
| } else { | |
| return Spliterators.spliterator(this, Spliterator.ORDERED); | |
| } | |
| } | |
| // ========== SequencedCollection ========== | |
| /** | |
| * {@inheritDoc} | |
| * | |
| * @implSpec | |
| * The implementation in this interface calls {@code add(0, e)}. | |
| * | |
| * @throws NullPointerException {@inheritDoc} | |
| * @throws UnsupportedOperationException {@inheritDoc} | |
| * @since 21 | |
| */ | |
| default void addFirst(E e) { | |
| this.add(0, e); | |
| } | |
| /** | |
| * {@inheritDoc} | |
| * | |
| * @implSpec | |
| * The implementation in this interface calls {@code add(e)}. | |
| * | |
| * @throws NullPointerException {@inheritDoc} | |
| * @throws UnsupportedOperationException {@inheritDoc} | |
| * @since 21 | |
| */ | |
| default void addLast(E e) { | |
| this.add(e); | |
| } | |
| /** | |
| * {@inheritDoc} | |
| * | |
| * @implSpec | |
| * If this List is not empty, the implementation in this interface returns the result | |
| * of calling {@code get(0)}. Otherwise, it throws {@code NoSuchElementException}. | |
| * | |
| * @throws NoSuchElementException {@inheritDoc} | |
| * @since 21 | |
| */ | |
| default E getFirst() { | |
| if (this.isEmpty()) { | |
| throw new NoSuchElementException(); | |
| } else { | |
| return this.get(0); | |
| } | |
| } | |
| /** | |
| * {@inheritDoc} | |
| * | |
| * @implSpec | |
| * If this List is not empty, the implementation in this interface returns the result | |
| * of calling {@code get(size() - 1)}. Otherwise, it throws {@code NoSuchElementException}. | |
| * | |
| * @throws NoSuchElementException {@inheritDoc} | |
| * @since 21 | |
| */ | |
| default E getLast() { | |
| if (this.isEmpty()) { | |
| throw new NoSuchElementException(); | |
| } else { | |
| return this.get(this.size() - 1); | |
| } | |
| } | |
| /** | |
| * {@inheritDoc} | |
| * | |
| * @implSpec | |
| * If this List is not empty, the implementation in this interface returns the result | |
| * of calling {@code remove(0)}. Otherwise, it throws {@code NoSuchElementException}. | |
| * | |
| * @throws NoSuchElementException {@inheritDoc} | |
| * @throws UnsupportedOperationException {@inheritDoc} | |
| * @since 21 | |
| */ | |
| default E removeFirst() { | |
| if (this.isEmpty()) { | |
| throw new NoSuchElementException(); | |
| } else { | |
| return this.remove(0); | |
| } | |
| } | |
| /** | |
| * {@inheritDoc} | |
| * | |
| * @implSpec | |
| * If this List is not empty, the implementation in this interface returns the result | |
| * of calling {@code remove(size() - 1)}. Otherwise, it throws {@code NoSuchElementException}. | |
| * | |
| * @throws NoSuchElementException {@inheritDoc} | |
| * @throws UnsupportedOperationException {@inheritDoc} | |
| * @since 21 | |
| */ | |
| default E removeLast() { | |
| if (this.isEmpty()) { | |
| throw new NoSuchElementException(); | |
| } else { | |
| return this.remove(this.size() - 1); | |
| } | |
| } | |
| /** | |
| * {@inheritDoc} | |
| * | |
| * @implSpec | |
| * The implementation in this interface returns a reverse-ordered List | |
| * view. The {@code reversed()} method of the view returns a reference | |
| * to this List. Other operations on the view are implemented via calls to | |
| * public methods on this List. The exact relationship between calls on the | |
| * view and calls on this List is unspecified. However, order-sensitive | |
| * operations generally behave as if they delegate to the appropriate method | |
| * with the opposite orientation. For example, calling {@code getFirst} on | |
| * the view might result in a call to {@code getLast} on this List. | |
| * | |
| * @return a reverse-ordered view of this collection, as a {@code List} | |
| * @since 21 | |
| */ | |
| default List<E> reversed() { | |
| return ReverseOrderListView.of(this, true); // we must assume it's modifiable | |
| } | |
| // ========== static methods ========== | |
| /** | |
| * Returns an unmodifiable list containing zero elements. | |
| * | |
| * See <a href="#unmodifiable">Unmodifiable Lists</a> for details. | |
| * | |
| * @param <E> the {@code List}'s element type | |
| * @return an empty {@code List} | |
| * | |
| * @since 9 | |
| */ | |
| @SuppressWarnings("unchecked") | |
| static <E> List<E> of() { | |
| return (List<E>) ImmutableCollections.EMPTY_LIST; | |
| } | |
| /** | |
| * Returns an unmodifiable list containing one element. | |
| * | |
| * See <a href="#unmodifiable">Unmodifiable Lists</a> for details. | |
| * | |
| * @param <E> the {@code List}'s element type | |
| * @param e1 the single element | |
| * @return a {@code List} containing the specified element | |
| * @throws NullPointerException if the element is {@code null} | |
| * | |
| * @since 9 | |
| */ | |
| static <E> List<E> of(E e1) { | |
| return new ImmutableCollections.List12<>(e1); | |
| } | |
| /** | |
| * Returns an unmodifiable list containing two elements. | |
| * | |
| * See <a href="#unmodifiable">Unmodifiable Lists</a> for details. | |
| * | |
| * @param <E> the {@code List}'s element type | |
| * @param e1 the first element | |
| * @param e2 the second element | |
| * @return a {@code List} containing the specified elements | |
| * @throws NullPointerException if an element is {@code null} | |
| * | |
| * @since 9 | |
| */ | |
| static <E> List<E> of(E e1, E e2) { | |
| return new ImmutableCollections.List12<>(e1, e2); | |
| } | |
| /** | |
| * Returns an unmodifiable list containing three elements. | |
| * | |
| * See <a href="#unmodifiable">Unmodifiable Lists</a> for details. | |
| * | |
| * @param <E> the {@code List}'s element type | |
| * @param e1 the first element | |
| * @param e2 the second element | |
| * @param e3 the third element | |
| * @return a {@code List} containing the specified elements | |
| * @throws NullPointerException if an element is {@code null} | |
| * | |
| * @since 9 | |
| */ | |
| static <E> List<E> of(E e1, E e2, E e3) { | |
| return ImmutableCollections.listFromTrustedArray(e1, e2, e3); | |
| } | |
| /** | |
| * Returns an unmodifiable list containing four elements. | |
| * | |
| * See <a href="#unmodifiable">Unmodifiable Lists</a> for details. | |
| * | |
| * @param <E> the {@code List}'s element type | |
| * @param e1 the first element | |
| * @param e2 the second element | |
| * @param e3 the third element | |
| * @param e4 the fourth element | |
| * @return a {@code List} containing the specified elements | |
| * @throws NullPointerException if an element is {@code null} | |
| * | |
| * @since 9 | |
| */ | |
| static <E> List<E> of(E e1, E e2, E e3, E e4) { | |
| return ImmutableCollections.listFromTrustedArray(e1, e2, e3, e4); | |
| } | |
| /** | |
| * Returns an unmodifiable list containing five elements. | |
| * | |
| * See <a href="#unmodifiable">Unmodifiable Lists</a> for details. | |
| * | |
| * @param <E> the {@code List}'s element type | |
| * @param e1 the first element | |
| * @param e2 the second element | |
| * @param e3 the third element | |
| * @param e4 the fourth element | |
| * @param e5 the fifth element | |
| * @return a {@code List} containing the specified elements | |
| * @throws NullPointerException if an element is {@code null} | |
| * | |
| * @since 9 | |
| */ | |
| static <E> List<E> of(E e1, E e2, E e3, E e4, E e5) { | |
| return ImmutableCollections.listFromTrustedArray(e1, e2, e3, e4, e5); | |
| } | |
| /** | |
| * Returns an unmodifiable list containing six elements. | |
| * | |
| * See <a href="#unmodifiable">Unmodifiable Lists</a> for details. | |
| * | |
| * @param <E> the {@code List}'s element type | |
| * @param e1 the first element | |
| * @param e2 the second element | |
| * @param e3 the third element | |
| * @param e4 the fourth element | |
| * @param e5 the fifth element | |
| * @param e6 the sixth element | |
| * @return a {@code List} containing the specified elements | |
| * @throws NullPointerException if an element is {@code null} | |
| * | |
| * @since 9 | |
| */ | |
| static <E> List<E> of(E e1, E e2, E e3, E e4, E e5, E e6) { | |
| return ImmutableCollections.listFromTrustedArray(e1, e2, e3, e4, e5, | |
| e6); | |
| } | |
| /** | |
| * Returns an unmodifiable list containing seven elements. | |
| * | |
| * See <a href="#unmodifiable">Unmodifiable Lists</a> for details. | |
| * | |
| * @param <E> the {@code List}'s element type | |
| * @param e1 the first element | |
| * @param e2 the second element | |
| * @param e3 the third element | |
| * @param e4 the fourth element | |
| * @param e5 the fifth element | |
| * @param e6 the sixth element | |
| * @param e7 the seventh element | |
| * @return a {@code List} containing the specified elements | |
| * @throws NullPointerException if an element is {@code null} | |
| * | |
| * @since 9 | |
| */ | |
| static <E> List<E> of(E e1, E e2, E e3, E e4, E e5, E e6, E e7) { | |
| return ImmutableCollections.listFromTrustedArray(e1, e2, e3, e4, e5, | |
| e6, e7); | |
| } | |
| /** | |
| * Returns an unmodifiable list containing eight elements. | |
| * | |
| * See <a href="#unmodifiable">Unmodifiable Lists</a> for details. | |
| * | |
| * @param <E> the {@code List}'s element type | |
| * @param e1 the first element | |
| * @param e2 the second element | |
| * @param e3 the third element | |
| * @param e4 the fourth element | |
| * @param e5 the fifth element | |
| * @param e6 the sixth element | |
| * @param e7 the seventh element | |
| * @param e8 the eighth element | |
| * @return a {@code List} containing the specified elements | |
| * @throws NullPointerException if an element is {@code null} | |
| * | |
| * @since 9 | |
| */ | |
| static <E> List<E> of(E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8) { | |
| return ImmutableCollections.listFromTrustedArray(e1, e2, e3, e4, e5, | |
| e6, e7, e8); | |
| } | |
| /** | |
| * Returns an unmodifiable list containing nine elements. | |
| * | |
| * See <a href="#unmodifiable">Unmodifiable Lists</a> for details. | |
| * | |
| * @param <E> the {@code List}'s element type | |
| * @param e1 the first element | |
| * @param e2 the second element | |
| * @param e3 the third element | |
| * @param e4 the fourth element | |
| * @param e5 the fifth element | |
| * @param e6 the sixth element | |
| * @param e7 the seventh element | |
| * @param e8 the eighth element | |
| * @param e9 the ninth element | |
| * @return a {@code List} containing the specified elements | |
| * @throws NullPointerException if an element is {@code null} | |
| * | |
| * @since 9 | |
| */ | |
| static <E> List<E> of(E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8, E e9) { | |
| return ImmutableCollections.listFromTrustedArray(e1, e2, e3, e4, e5, | |
| e6, e7, e8, e9); | |
| } | |
| /** | |
| * Returns an unmodifiable list containing ten elements. | |
| * | |
| * See <a href="#unmodifiable">Unmodifiable Lists</a> for details. | |
| * | |
| * @param <E> the {@code List}'s element type | |
| * @param e1 the first element | |
| * @param e2 the second element | |
| * @param e3 the third element | |
| * @param e4 the fourth element | |
| * @param e5 the fifth element | |
| * @param e6 the sixth element | |
| * @param e7 the seventh element | |
| * @param e8 the eighth element | |
| * @param e9 the ninth element | |
| * @param e10 the tenth element | |
| * @return a {@code List} containing the specified elements | |
| * @throws NullPointerException if an element is {@code null} | |
| * | |
| * @since 9 | |
| */ | |
| static <E> List<E> of(E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8, E e9, E e10) { | |
| return ImmutableCollections.listFromTrustedArray(e1, e2, e3, e4, e5, | |
| e6, e7, e8, e9, e10); | |
| } | |
| /** | |
| * Returns an unmodifiable list containing an arbitrary number of elements. | |
| * See <a href="#unmodifiable">Unmodifiable Lists</a> for details. | |
| * | |
| * @apiNote | |
| * This method also accepts a single array as an argument. The element type of | |
| * the resulting list will be the component type of the array, and the size of | |
| * the list will be equal to the length of the array. To create a list with | |
| * a single element that is an array, do the following: | |
| * | |
| * <pre>{@code | |
| * String[] array = ... ; | |
| * List<String[]> list = List.<String[]>of(array); | |
| * }</pre> | |
| * | |
| * This will cause the {@link List#of(Object) List.of(E)} method | |
| * to be invoked instead. | |
| * | |
| * @param <E> the {@code List}'s element type | |
| * @param elements the elements to be contained in the list | |
| * @return a {@code List} containing the specified elements | |
| * @throws NullPointerException if an element is {@code null} or if the array is {@code null} | |
| * | |
| * @since 9 | |
| */ | |
| @SafeVarargs | |
| @SuppressWarnings("varargs") | |
| static <E> List<E> of(E... elements) { | |
| switch (elements.length) { // implicit null check of elements | |
| case 0: | |
| @SuppressWarnings("unchecked") | |
| var list = (List<E>) ImmutableCollections.EMPTY_LIST; | |
| return list; | |
| case 1: | |
| return new ImmutableCollections.List12<>(elements[0]); | |
| case 2: | |
| return new ImmutableCollections.List12<>(elements[0], elements[1]); | |
| default: | |
| return ImmutableCollections.listFromArray(elements); | |
| } | |
| } | |
| /** | |
| * Returns an <a href="#unmodifiable">unmodifiable List</a> containing the elements of | |
| * the given Collection, in its iteration order. The given Collection must not be null, | |
| * and it must not contain any null elements. If the given Collection is subsequently | |
| * modified, the returned List will not reflect such modifications. | |
| * | |
| * @implNote | |
| * If the given Collection is an <a href="#unmodifiable">unmodifiable List</a>, | |
| * calling copyOf will generally not create a copy. | |
| * | |
| * @param <E> the {@code List}'s element type | |
| * @param coll a {@code Collection} from which elements are drawn, must be non-null | |
| * @return a {@code List} containing the elements of the given {@code Collection} | |
| * @throws NullPointerException if coll is null, or if it contains any nulls | |
| * @since 10 | |
| */ | |
| static <E> List<E> copyOf(Collection<? extends E> coll) { | |
| return ImmutableCollections.listCopy(coll); | |
| } | |
| } |