diff -r d0f57d3ea898 -r d382dacfd73f rt/emul/compact/src/main/java/java/util/LinkedList.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/rt/emul/compact/src/main/java/java/util/LinkedList.java Tue Feb 26 16:54:16 2013 +0100 @@ -0,0 +1,1100 @@ +/* + * Copyright (c) 1997, 2011, 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; + +/** + * Doubly-linked list implementation of the {@code List} and {@code Deque} + * interfaces. Implements all optional list operations, and permits all + * elements (including {@code null}). + * + *

All of the operations perform as could be expected for a doubly-linked + * list. Operations that index into the list will traverse the list from + * the beginning or the end, whichever is closer to the specified index. + * + *

Note that this implementation is not synchronized. + * If multiple threads access a linked list concurrently, and at least + * one of the threads modifies the list structurally, it must be + * synchronized externally. (A structural modification is any operation + * that adds or deletes one or more elements; merely setting the value of + * an element is not a structural modification.) This is typically + * accomplished by synchronizing on some object that naturally + * encapsulates the list. + * + * If no such object exists, the list should be "wrapped" using the + * {@link Collections#synchronizedList Collections.synchronizedList} + * method. This is best done at creation time, to prevent accidental + * unsynchronized access to the list:

+ *   List list = Collections.synchronizedList(new LinkedList(...));
+ * + *

The iterators returned by this class's {@code iterator} and + * {@code listIterator} methods are fail-fast: if the list is + * structurally modified at any time after the iterator is created, in + * any way except through the Iterator's own {@code remove} or + * {@code add} methods, the iterator will throw a {@link + * ConcurrentModificationException}. Thus, in the face of concurrent + * modification, the iterator fails quickly and cleanly, rather than + * risking arbitrary, non-deterministic behavior at an undetermined + * time in the future. + * + *

Note that the fail-fast behavior of an iterator cannot be guaranteed + * as it is, generally speaking, impossible to make any hard guarantees in the + * presence of unsynchronized concurrent modification. Fail-fast iterators + * throw {@code ConcurrentModificationException} on a best-effort basis. + * Therefore, it would be wrong to write a program that depended on this + * exception for its correctness: the fail-fast behavior of iterators + * should be used only to detect bugs. + * + *

This class is a member of the + * + * Java Collections Framework. + * + * @author Josh Bloch + * @see List + * @see ArrayList + * @since 1.2 + * @param the type of elements held in this collection + */ + +public class LinkedList + extends AbstractSequentialList + implements List, Deque, Cloneable, java.io.Serializable +{ + transient int size = 0; + + /** + * Pointer to first node. + * Invariant: (first == null && last == null) || + * (first.prev == null && first.item != null) + */ + transient Node first; + + /** + * Pointer to last node. + * Invariant: (first == null && last == null) || + * (last.next == null && last.item != null) + */ + transient Node last; + + /** + * Constructs an empty list. + */ + public LinkedList() { + } + + /** + * Constructs a list containing the elements of the specified + * collection, in the order they are returned by the collection's + * iterator. + * + * @param c the collection whose elements are to be placed into this list + * @throws NullPointerException if the specified collection is null + */ + public LinkedList(Collection c) { + this(); + addAll(c); + } + + /** + * Links e as first element. + */ + private void linkFirst(E e) { + final Node f = first; + final Node newNode = new Node<>(null, e, f); + first = newNode; + if (f == null) + last = newNode; + else + f.prev = newNode; + size++; + modCount++; + } + + /** + * Links e as last element. + */ + void linkLast(E e) { + final Node l = last; + final Node newNode = new Node<>(l, e, null); + last = newNode; + if (l == null) + first = newNode; + else + l.next = newNode; + size++; + modCount++; + } + + /** + * Inserts element e before non-null Node succ. + */ + void linkBefore(E e, Node succ) { + // assert succ != null; + final Node pred = succ.prev; + final Node newNode = new Node<>(pred, e, succ); + succ.prev = newNode; + if (pred == null) + first = newNode; + else + pred.next = newNode; + size++; + modCount++; + } + + /** + * Unlinks non-null first node f. + */ + private E unlinkFirst(Node f) { + // assert f == first && f != null; + final E element = f.item; + final Node next = f.next; + f.item = null; + f.next = null; // help GC + first = next; + if (next == null) + last = null; + else + next.prev = null; + size--; + modCount++; + return element; + } + + /** + * Unlinks non-null last node l. + */ + private E unlinkLast(Node l) { + // assert l == last && l != null; + final E element = l.item; + final Node prev = l.prev; + l.item = null; + l.prev = null; // help GC + last = prev; + if (prev == null) + first = null; + else + prev.next = null; + size--; + modCount++; + return element; + } + + /** + * Unlinks non-null node x. + */ + E unlink(Node x) { + // assert x != null; + final E element = x.item; + final Node next = x.next; + final Node prev = x.prev; + + if (prev == null) { + first = next; + } else { + prev.next = next; + x.prev = null; + } + + if (next == null) { + last = prev; + } else { + next.prev = prev; + x.next = null; + } + + x.item = null; + size--; + modCount++; + return element; + } + + /** + * Returns the first element in this list. + * + * @return the first element in this list + * @throws NoSuchElementException if this list is empty + */ + public E getFirst() { + final Node f = first; + if (f == null) + throw new NoSuchElementException(); + return f.item; + } + + /** + * Returns the last element in this list. + * + * @return the last element in this list + * @throws NoSuchElementException if this list is empty + */ + public E getLast() { + final Node l = last; + if (l == null) + throw new NoSuchElementException(); + return l.item; + } + + /** + * Removes and returns the first element from this list. + * + * @return the first element from this list + * @throws NoSuchElementException if this list is empty + */ + public E removeFirst() { + final Node f = first; + if (f == null) + throw new NoSuchElementException(); + return unlinkFirst(f); + } + + /** + * Removes and returns the last element from this list. + * + * @return the last element from this list + * @throws NoSuchElementException if this list is empty + */ + public E removeLast() { + final Node l = last; + if (l == null) + throw new NoSuchElementException(); + return unlinkLast(l); + } + + /** + * Inserts the specified element at the beginning of this list. + * + * @param e the element to add + */ + public void addFirst(E e) { + linkFirst(e); + } + + /** + * Appends the specified element to the end of this list. + * + *

This method is equivalent to {@link #add}. + * + * @param e the element to add + */ + public void addLast(E e) { + linkLast(e); + } + + /** + * 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 + * (o==null ? e==null : o.equals(e)). + * + * @param o element whose presence in this list is to be tested + * @return {@code true} if this list contains the specified element + */ + public boolean contains(Object o) { + return indexOf(o) != -1; + } + + /** + * Returns the number of elements in this list. + * + * @return the number of elements in this list + */ + public int size() { + return size; + } + + /** + * Appends the specified element to the end of this list. + * + *

This method is equivalent to {@link #addLast}. + * + * @param e element to be appended to this list + * @return {@code true} (as specified by {@link Collection#add}) + */ + public boolean add(E e) { + linkLast(e); + return true; + } + + /** + * Removes the first occurrence of the specified element from this list, + * if it is present. If this list does not contain the element, it is + * unchanged. More formally, removes the element with the lowest index + * {@code i} such that + * (o==null ? get(i)==null : o.equals(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 + */ + public boolean remove(Object o) { + if (o == null) { + for (Node x = first; x != null; x = x.next) { + if (x.item == null) { + unlink(x); + return true; + } + } + } else { + for (Node x = first; x != null; x = x.next) { + if (o.equals(x.item)) { + unlink(x); + return true; + } + } + } + return false; + } + + /** + * 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. 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 NullPointerException if the specified collection is null + */ + public boolean addAll(Collection c) { + return addAll(size, c); + } + + /** + * Inserts all of the elements in the specified collection into this + * list, starting at the specified position. 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 the list in the order that they are returned by the + * specified collection's iterator. + * + * @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 IndexOutOfBoundsException {@inheritDoc} + * @throws NullPointerException if the specified collection is null + */ + public boolean addAll(int index, Collection c) { + checkPositionIndex(index); + + Object[] a = c.toArray(); + int numNew = a.length; + if (numNew == 0) + return false; + + Node pred, succ; + if (index == size) { + succ = null; + pred = last; + } else { + succ = node(index); + pred = succ.prev; + } + + for (Object o : a) { + @SuppressWarnings("unchecked") E e = (E) o; + Node newNode = new Node<>(pred, e, null); + if (pred == null) + first = newNode; + else + pred.next = newNode; + pred = newNode; + } + + if (succ == null) { + last = pred; + } else { + pred.next = succ; + succ.prev = pred; + } + + size += numNew; + modCount++; + return true; + } + + /** + * Removes all of the elements from this list. + * The list will be empty after this call returns. + */ + public void clear() { + // Clearing all of the links between nodes is "unnecessary", but: + // - helps a generational GC if the discarded nodes inhabit + // more than one generation + // - is sure to free memory even if there is a reachable Iterator + for (Node x = first; x != null; ) { + Node next = x.next; + x.item = null; + x.next = null; + x.prev = null; + x = next; + } + first = last = null; + size = 0; + modCount++; + } + + + // 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 {@inheritDoc} + */ + public E get(int index) { + checkElementIndex(index); + return node(index).item; + } + + /** + * Replaces the element at the specified position in this list with the + * specified element. + * + * @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 IndexOutOfBoundsException {@inheritDoc} + */ + public E set(int index, E element) { + checkElementIndex(index); + Node x = node(index); + E oldVal = x.item; + x.item = element; + return oldVal; + } + + /** + * Inserts the specified element at the specified position in this list. + * 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 IndexOutOfBoundsException {@inheritDoc} + */ + public void add(int index, E element) { + checkPositionIndex(index); + + if (index == size) + linkLast(element); + else + linkBefore(element, node(index)); + } + + /** + * Removes the element at the specified position in this list. 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 IndexOutOfBoundsException {@inheritDoc} + */ + public E remove(int index) { + checkElementIndex(index); + return unlink(node(index)); + } + + /** + * Tells if the argument is the index of an existing element. + */ + private boolean isElementIndex(int index) { + return index >= 0 && index < size; + } + + /** + * Tells if the argument is the index of a valid position for an + * iterator or an add operation. + */ + private boolean isPositionIndex(int index) { + return index >= 0 && index <= size; + } + + /** + * Constructs an IndexOutOfBoundsException detail message. + * Of the many possible refactorings of the error handling code, + * this "outlining" performs best with both server and client VMs. + */ + private String outOfBoundsMsg(int index) { + return "Index: "+index+", Size: "+size; + } + + private void checkElementIndex(int index) { + if (!isElementIndex(index)) + throw new IndexOutOfBoundsException(outOfBoundsMsg(index)); + } + + private void checkPositionIndex(int index) { + if (!isPositionIndex(index)) + throw new IndexOutOfBoundsException(outOfBoundsMsg(index)); + } + + /** + * Returns the (non-null) Node at the specified element index. + */ + Node node(int index) { + // assert isElementIndex(index); + + if (index < (size >> 1)) { + Node x = first; + for (int i = 0; i < index; i++) + x = x.next; + return x; + } else { + Node x = last; + for (int i = size - 1; i > index; i--) + x = x.prev; + return x; + } + } + + // 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 + * (o==null ? get(i)==null : o.equals(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 + */ + public int indexOf(Object o) { + int index = 0; + if (o == null) { + for (Node x = first; x != null; x = x.next) { + if (x.item == null) + return index; + index++; + } + } else { + for (Node x = first; x != null; x = x.next) { + if (o.equals(x.item)) + return index; + index++; + } + } + return -1; + } + + /** + * 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 + * (o==null ? get(i)==null : o.equals(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 + */ + public int lastIndexOf(Object o) { + int index = size; + if (o == null) { + for (Node x = last; x != null; x = x.prev) { + index--; + if (x.item == null) + return index; + } + } else { + for (Node x = last; x != null; x = x.prev) { + index--; + if (o.equals(x.item)) + return index; + } + } + return -1; + } + + // Queue operations. + + /** + * Retrieves, but does not remove, the head (first element) of this list. + * + * @return the head of this list, or {@code null} if this list is empty + * @since 1.5 + */ + public E peek() { + final Node f = first; + return (f == null) ? null : f.item; + } + + /** + * Retrieves, but does not remove, the head (first element) of this list. + * + * @return the head of this list + * @throws NoSuchElementException if this list is empty + * @since 1.5 + */ + public E element() { + return getFirst(); + } + + /** + * Retrieves and removes the head (first element) of this list. + * + * @return the head of this list, or {@code null} if this list is empty + * @since 1.5 + */ + public E poll() { + final Node f = first; + return (f == null) ? null : unlinkFirst(f); + } + + /** + * Retrieves and removes the head (first element) of this list. + * + * @return the head of this list + * @throws NoSuchElementException if this list is empty + * @since 1.5 + */ + public E remove() { + return removeFirst(); + } + + /** + * Adds the specified element as the tail (last element) of this list. + * + * @param e the element to add + * @return {@code true} (as specified by {@link Queue#offer}) + * @since 1.5 + */ + public boolean offer(E e) { + return add(e); + } + + // Deque operations + /** + * Inserts the specified element at the front of this list. + * + * @param e the element to insert + * @return {@code true} (as specified by {@link Deque#offerFirst}) + * @since 1.6 + */ + public boolean offerFirst(E e) { + addFirst(e); + return true; + } + + /** + * Inserts the specified element at the end of this list. + * + * @param e the element to insert + * @return {@code true} (as specified by {@link Deque#offerLast}) + * @since 1.6 + */ + public boolean offerLast(E e) { + addLast(e); + return true; + } + + /** + * Retrieves, but does not remove, the first element of this list, + * or returns {@code null} if this list is empty. + * + * @return the first element of this list, or {@code null} + * if this list is empty + * @since 1.6 + */ + public E peekFirst() { + final Node f = first; + return (f == null) ? null : f.item; + } + + /** + * Retrieves, but does not remove, the last element of this list, + * or returns {@code null} if this list is empty. + * + * @return the last element of this list, or {@code null} + * if this list is empty + * @since 1.6 + */ + public E peekLast() { + final Node l = last; + return (l == null) ? null : l.item; + } + + /** + * Retrieves and removes the first element of this list, + * or returns {@code null} if this list is empty. + * + * @return the first element of this list, or {@code null} if + * this list is empty + * @since 1.6 + */ + public E pollFirst() { + final Node f = first; + return (f == null) ? null : unlinkFirst(f); + } + + /** + * Retrieves and removes the last element of this list, + * or returns {@code null} if this list is empty. + * + * @return the last element of this list, or {@code null} if + * this list is empty + * @since 1.6 + */ + public E pollLast() { + final Node l = last; + return (l == null) ? null : unlinkLast(l); + } + + /** + * Pushes an element onto the stack represented by this list. In other + * words, inserts the element at the front of this list. + * + *

This method is equivalent to {@link #addFirst}. + * + * @param e the element to push + * @since 1.6 + */ + public void push(E e) { + addFirst(e); + } + + /** + * Pops an element from the stack represented by this list. In other + * words, removes and returns the first element of this list. + * + *

This method is equivalent to {@link #removeFirst()}. + * + * @return the element at the front of this list (which is the top + * of the stack represented by this list) + * @throws NoSuchElementException if this list is empty + * @since 1.6 + */ + public E pop() { + return removeFirst(); + } + + /** + * Removes the first occurrence of the specified element in this + * list (when traversing the list from head to tail). If the list + * does not contain the element, it is unchanged. + * + * @param o element to be removed from this list, if present + * @return {@code true} if the list contained the specified element + * @since 1.6 + */ + public boolean removeFirstOccurrence(Object o) { + return remove(o); + } + + /** + * Removes the last occurrence of the specified element in this + * list (when traversing the list from head to tail). If the list + * does not contain the element, it is unchanged. + * + * @param o element to be removed from this list, if present + * @return {@code true} if the list contained the specified element + * @since 1.6 + */ + public boolean removeLastOccurrence(Object o) { + if (o == null) { + for (Node x = last; x != null; x = x.prev) { + if (x.item == null) { + unlink(x); + return true; + } + } + } else { + for (Node x = last; x != null; x = x.prev) { + if (o.equals(x.item)) { + unlink(x); + return true; + } + } + } + return false; + } + + /** + * Returns a list-iterator of the elements in this list (in proper + * sequence), starting at the specified position in the list. + * Obeys the general contract of {@code List.listIterator(int)}.

+ * + * The list-iterator is fail-fast: if the list is structurally + * modified at any time after the Iterator is created, in any way except + * through the list-iterator's own {@code remove} or {@code add} + * methods, the list-iterator will throw a + * {@code ConcurrentModificationException}. Thus, in the face of + * concurrent modification, the iterator fails quickly and cleanly, rather + * than risking arbitrary, non-deterministic behavior at an undetermined + * time in the future. + * + * @param index index of the first element to be returned from the + * list-iterator (by a call to {@code next}) + * @return a ListIterator of the elements in this list (in proper + * sequence), starting at the specified position in the list + * @throws IndexOutOfBoundsException {@inheritDoc} + * @see List#listIterator(int) + */ + public ListIterator listIterator(int index) { + checkPositionIndex(index); + return new ListItr(index); + } + + private class ListItr implements ListIterator { + private Node lastReturned = null; + private Node next; + private int nextIndex; + private int expectedModCount = modCount; + + ListItr(int index) { + // assert isPositionIndex(index); + next = (index == size) ? null : node(index); + nextIndex = index; + } + + public boolean hasNext() { + return nextIndex < size; + } + + public E next() { + checkForComodification(); + if (!hasNext()) + throw new NoSuchElementException(); + + lastReturned = next; + next = next.next; + nextIndex++; + return lastReturned.item; + } + + public boolean hasPrevious() { + return nextIndex > 0; + } + + public E previous() { + checkForComodification(); + if (!hasPrevious()) + throw new NoSuchElementException(); + + lastReturned = next = (next == null) ? last : next.prev; + nextIndex--; + return lastReturned.item; + } + + public int nextIndex() { + return nextIndex; + } + + public int previousIndex() { + return nextIndex - 1; + } + + public void remove() { + checkForComodification(); + if (lastReturned == null) + throw new IllegalStateException(); + + Node lastNext = lastReturned.next; + unlink(lastReturned); + if (next == lastReturned) + next = lastNext; + else + nextIndex--; + lastReturned = null; + expectedModCount++; + } + + public void set(E e) { + if (lastReturned == null) + throw new IllegalStateException(); + checkForComodification(); + lastReturned.item = e; + } + + public void add(E e) { + checkForComodification(); + lastReturned = null; + if (next == null) + linkLast(e); + else + linkBefore(e, next); + nextIndex++; + expectedModCount++; + } + + final void checkForComodification() { + if (modCount != expectedModCount) + throw new ConcurrentModificationException(); + } + } + + private static class Node { + E item; + Node next; + Node prev; + + Node(Node prev, E element, Node next) { + this.item = element; + this.next = next; + this.prev = prev; + } + } + + /** + * @since 1.6 + */ + public Iterator descendingIterator() { + return new DescendingIterator(); + } + + /** + * Adapter to provide descending iterators via ListItr.previous + */ + private class DescendingIterator implements Iterator { + private final ListItr itr = new ListItr(size()); + public boolean hasNext() { + return itr.hasPrevious(); + } + public E next() { + return itr.previous(); + } + public void remove() { + itr.remove(); + } + } + + @SuppressWarnings("unchecked") + private LinkedList superClone() { + try { + return (LinkedList) super.clone(); + } catch (CloneNotSupportedException e) { + throw new InternalError(); + } + } + + /** + * Returns a shallow copy of this {@code LinkedList}. (The elements + * themselves are not cloned.) + * + * @return a shallow copy of this {@code LinkedList} instance + */ + public Object clone() { + LinkedList clone = superClone(); + + // Put clone into "virgin" state + clone.first = clone.last = null; + clone.size = 0; + clone.modCount = 0; + + // Initialize clone with our elements + for (Node x = first; x != null; x = x.next) + clone.add(x.item); + + return clone; + } + + /** + * Returns an array containing all of the elements in this list + * in proper sequence (from first to last element). + * + *

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). The caller is thus free to modify the returned array. + * + *

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 + */ + public Object[] toArray() { + Object[] result = new Object[size]; + int i = 0; + for (Node x = first; x != null; x = x.next) + result[i++] = x.item; + return result; + } + + /** + * 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. + * + *

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 only if + * the caller knows that the list does not contain any null elements.) + * + *

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. + * + *

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}: + * + * 

+     *     String[] y = x.toArray(new String[0]);
+ * + * Note that {@code toArray(new Object[0])} is identical in function to + * {@code toArray()}. + * + * @param a the array into which the elements of the 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 the 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 + */ + @SuppressWarnings("unchecked") + public T[] toArray(T[] a) { + if (a.length < size) + a = (T[])java.lang.reflect.Array.newInstance( + a.getClass().getComponentType(), size); + int i = 0; + Object[] result = a; + for (Node x = first; x != null; x = x.next) + result[i++] = x.item; + + if (a.length > size) + a[size] = null; + + return a; + } + + private static final long serialVersionUID = 876323262645176354L; + +}