/*
 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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package java.util;

import java.util.function.UnaryOperator;

/**
 * An ordered collection (also known as a <i>sequence</i>). The user of this
 * interface 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>They are <a href="../lang/doc-files/ValueBased.html">value-based</a>.
 * Callers should make no assumptions about the identity of the returned instances.
 * Factories are free to create new instances or reuse existing ones. Therefore,
 * identity-sensitive operations on these instances (reference equality ({@code ==}),
 * identity hash code, and synchronization) are unreliable and should be avoided.
 * <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 Collection<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. 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 this list is unmodifiable.
 * Implementations may throw this exception if an element
 * cannot be replaced or if, in general, modification is not
 * supported
 * @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}. 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 list's list-iterator does
 * not support the {@code set} operation
 * @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", "rawtypes"})
 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);
 }
 }

 /**
 * 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
 */
 static <E> List<E> of() {
 return ImmutableCollections.emptyList();
 }

 /**
 * 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 new ImmutableCollections.ListN<>(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 new ImmutableCollections.ListN<>(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 new ImmutableCollections.ListN<>(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 new ImmutableCollections.ListN<>(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 new ImmutableCollections.ListN<>(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 new ImmutableCollections.ListN<>(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 new ImmutableCollections.ListN<>(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 new ImmutableCollections.ListN<>(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:
 return ImmutableCollections.emptyList();
 case 1:
 return new ImmutableCollections.List12<>(elements[0]);
 case 2:
 return new ImmutableCollections.List12<>(elements[0], elements[1]);
 default:
 return new ImmutableCollections.ListN<>(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);
 }
}