< prev index next >
src/java.desktop/share/classes/sun/awt/util/IdentityLinkedList.java
Print this page
*** 33,54 ****
import java.util.List;
import java.util.ListIterator;
import java.util.NoSuchElementException;
/**
! * Linked list implementation of the <tt>List</tt> interface. Implements all
* optional list operations, and permits all elements (including
! * <tt>null</tt>). In addition to implementing the <tt>List</tt> interface,
! * the <tt>IdentityLinkedList</tt> class provides uniformly named methods to
! * <tt>get</tt>, <tt>remove</tt> and <tt>insert</tt> an element at the
* beginning and end of the list. These operations allow linked lists to be
* used as a stack, {@linkplain java.util.Queue queue}, or {@linkplain Deque
* double-ended queue}. <p>
*
! * The class implements the <tt>Deque</tt> interface, providing
! * first-in-first-out queue operations for <tt>add</tt>,
! * <tt>poll</tt>, along with other stack and deque operations.<p>
*
* 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.<p>
*
--- 33,54 ----
import java.util.List;
import java.util.ListIterator;
import java.util.NoSuchElementException;
/**
! * Linked list implementation of the {@code List} interface. Implements all
* optional list operations, and permits all elements (including
! * {@code null}). In addition to implementing the {@code List} interface,
! * the {@code IdentityLinkedList} class provides uniformly named methods to
! * {@code get}, {@code remove} and {@code insert} an element at the
* beginning and end of the list. These operations allow linked lists to be
* used as a stack, {@linkplain java.util.Queue queue}, or {@linkplain Deque
* double-ended queue}. <p>
*
! * The class implements the {@code Deque} interface, providing
! * first-in-first-out queue operations for {@code add},
! * {@code poll}, along with other stack and deque operations.<p>
*
* 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.<p>
*
*** 65,88 ****
* {@link java.util.Collections#synchronizedList Collections.synchronizedList}
* method. This is best done at creation time, to prevent accidental
* unsynchronized access to the list:<pre>
* List list = Collections.synchronizedList(new IdentityLinkedList(...));</pre>
*
! * <p>The iterators returned by this class's <tt>iterator</tt> and
! * <tt>listIterator</tt> methods are <i>fail-fast</i>: if the list is
* structurally modified at any time after the iterator is created, in
! * any way except through the Iterator's own <tt>remove</tt> or
! * <tt>add</tt> 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.
*
* <p>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 <tt>ConcurrentModificationException</tt> on a best-effort basis.
* Therefore, it would be wrong to write a program that depended on this
* exception for its correctness: <i>the fail-fast behavior of iterators
* should be used only to detect bugs.</i>
*/
--- 65,88 ----
* {@link java.util.Collections#synchronizedList Collections.synchronizedList}
* method. This is best done at creation time, to prevent accidental
* unsynchronized access to the list:<pre>
* List list = Collections.synchronizedList(new IdentityLinkedList(...));</pre>
*
! * <p>The iterators returned by this class's {@code iterator} and
! * {@code listIterator} methods are <i>fail-fast</i>: 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.
*
* <p>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: <i>the fail-fast behavior of iterators
* should be used only to detect bugs.</i>
*/
*** 178,194 ****
public void addLast(E e) {
addBefore(e, header);
}
/**
! * Returns <tt>true</tt> if this list contains the specified element.
! * More formally, returns <tt>true</tt> if and only if this list contains
! * at least one element <tt>e</tt> such that
! * <tt>(o==null ? e==null : o == e)</tt>.
*
* @param o element whose presence in this list is to be tested
! * @return <tt>true</tt> if this list contains the specified element
*/
public boolean contains(Object o) {
return indexOf(o) != -1;
}
--- 178,194 ----
public void addLast(E e) {
addBefore(e, header);
}
/**
! * 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
*/
public boolean contains(Object o) {
return indexOf(o) != -1;
}
*** 205,232 ****
* Appends the specified element to the end of this list.
*
* <p>This method is equivalent to {@link #addLast}.
*
* @param e element to be appended to this list
! * @return <tt>true</tt> (as specified by {@link Collection#add})
*/
public boolean add(E e) {
addBefore(e, header);
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
! * <tt>i</tt> such that <tt>get(i)==o</tt>
! * (if such an element exists). Returns <tt>true</tt> 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 <tt>true</tt> if this list contained the specified element
*/
public boolean remove(Object o) {
for (Entry<E> e = header.next; e != header; e = e.next) {
if (o == e.element) {
remove(e);
--- 205,232 ----
* Appends the specified element to the end of this list.
*
* <p>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) {
addBefore(e, header);
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 {@code get(i)==o}
! * (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) {
for (Entry<E> e = header.next; e != header; e = e.next) {
if (o == e.element) {
remove(e);
*** 243,253 ****
* 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 <tt>true</tt> if this list changed as a result of the call
* @throws NullPointerException if the specified collection is null
*/
public boolean addAll(Collection<? extends E> c) {
return addAll(size, c);
}
--- 243,253 ----
* 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<? extends E> c) {
return addAll(size, c);
}
*** 261,271 ****
* 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 <tt>true</tt> 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<? extends E> c) {
if (index < 0 || index > size)
--- 261,271 ----
* 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<? extends E> c) {
if (index < 0 || index > size)
*** 386,397 ****
// 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 <tt>i</tt> such that
! * <tt>get(i)==o</tt>,
* 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
--- 386,397 ----
// 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 get(i)==o},
* 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
*** 408,419 ****
}
/**
* 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 <tt>i</tt> such that
! * <tt>get(i)==o</tt>,
* 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
--- 408,419 ----
}
/**
* 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 get(i)==o},
* 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
*** 431,441 ****
// Queue operations.
/**
* Retrieves, but does not remove, the head (first element) of this list.
! * @return the head of this list, or <tt>null</tt> if this list is empty
* @since 1.5
*/
public E peek() {
if (size==0)
return null;
--- 431,441 ----
// 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() {
if (size==0)
return null;
*** 452,462 ****
return getFirst();
}
/**
* Retrieves and removes the head (first element) of this list
! * @return the head of this list, or <tt>null</tt> if this list is empty
* @since 1.5
*/
public E poll() {
if (size==0)
return null;
--- 452,462 ----
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() {
if (size==0)
return null;
*** 476,486 ****
/**
* Adds the specified element as the tail (last element) of this list.
*
* @param e the element to add
! * @return <tt>true</tt> (as specified by {@link java.util.Queue#offer})
* @since 1.5
*/
public boolean offer(E e) {
return add(e);
}
--- 476,486 ----
/**
* 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 java.util.Queue#offer})
* @since 1.5
*/
public boolean offer(E e) {
return add(e);
}
*** 488,498 ****
// Deque operations
/**
* Inserts the specified element at the front of this list.
*
* @param e the element to insert
! * @return <tt>true</tt> (as specified by {@link Deque#offerFirst})
* @since 1.6
*/
public boolean offerFirst(E e) {
addFirst(e);
return true;
--- 488,498 ----
// 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;
*** 500,522 ****
/**
* Inserts the specified element at the end of this list.
*
* @param e the element to insert
! * @return <tt>true</tt> (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 <tt>null</tt> if this list is empty.
*
! * @return the first element of this list, or <tt>null</tt>
* if this list is empty
* @since 1.6
*/
public E peekFirst() {
if (size==0)
--- 500,522 ----
/**
* 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() {
if (size==0)
*** 524,536 ****
return getFirst();
}
/**
* Retrieves, but does not remove, the last element of this list,
! * or returns <tt>null</tt> if this list is empty.
*
! * @return the last element of this list, or <tt>null</tt>
* if this list is empty
* @since 1.6
*/
public E peekLast() {
if (size==0)
--- 524,536 ----
return getFirst();
}
/**
* 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() {
if (size==0)
*** 538,550 ****
return getLast();
}
/**
* Retrieves and removes the first element of this list,
! * or returns <tt>null</tt> if this list is empty.
*
! * @return the first element of this list, or <tt>null</tt> if
* this list is empty
* @since 1.6
*/
public E pollFirst() {
if (size==0)
--- 538,550 ----
return getLast();
}
/**
* 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() {
if (size==0)
*** 552,564 ****
return removeFirst();
}
/**
* Retrieves and removes the last element of this list,
! * or returns <tt>null</tt> if this list is empty.
*
! * @return the last element of this list, or <tt>null</tt> if
* this list is empty
* @since 1.6
*/
public E pollLast() {
if (size==0)
--- 552,564 ----
return removeFirst();
}
/**
* 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() {
if (size==0)
*** 598,608 ****
* 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 <tt>true</tt> if the list contained the specified element
* @since 1.6
*/
public boolean removeFirstOccurrence(Object o) {
return remove(o);
}
--- 598,608 ----
* 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);
}
*** 611,621 ****
* 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 <tt>true</tt> if the list contained the specified element
* @since 1.6
*/
public boolean removeLastOccurrence(Object o) {
for (Entry<E> e = header.previous; e != header; e = e.previous) {
if (o == e.element) {
--- 611,621 ----
* 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) {
for (Entry<E> e = header.previous; e != header; e = e.previous) {
if (o == e.element) {
*** 627,649 ****
}
/**
* 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 <tt>List.listIterator(int)</tt>.<p>
*
* The list-iterator is <i>fail-fast</i>: if the list is structurally
* modified at any time after the Iterator is created, in any way except
! * through the list-iterator's own <tt>remove</tt> or <tt>add</tt>
* methods, the list-iterator will throw a
! * <tt>ConcurrentModificationException</tt>. 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 <tt>next</tt>)
* @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)
*/
--- 627,649 ----
}
/**
* 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)}.<p>
*
* The list-iterator is <i>fail-fast</i>: 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)
*/
*** 832,859 ****
* 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 <tt>null</tt>.
* (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 <tt>x</tt> is a list known to contain only strings.
* The following code can be used to dump the list into a newly
! * allocated array of <tt>String</tt>:
*
* <pre>
* String[] y = x.toArray(new String[0]);</pre>
*
! * Note that <tt>toArray(new Object[0])</tt> is identical in function to
! * <tt>toArray()</tt>.
*
* @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
--- 832,859 ----
* 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>
* 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 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
< prev index next >