java.util.LinkedList Maven / Gradle / Ivy
/*
This is not an official specification document, and usage is restricted.
NOTICE
(c) 2005-2007 Sun Microsystems, Inc. All Rights Reserved.
Neither this file nor any files generated from it describe a complete
specification, and they may only be used as described below. For
example, no permission is given for you to incorporate this file, in
whole or in part, in an implementation of a Java specification.
Sun Microsystems Inc. owns the copyright in this file and it is provided
to you for informative, as opposed to normative, use. The file and any
files generated from it may be used to generate other informative
documentation, such as a unified set of documents of API signatures for
a platform that includes technologies expressed as Java APIs. The file
may also be used to produce "compilation stubs," which allow
applications to be compiled and validated for such platforms.
Any work generated from this file, such as unified javadocs or compiled
stub files, must be accompanied by this notice in its entirety.
This work corresponds to the API signatures of JSR 219: Foundation
Profile 1.1. In the event of a discrepency between this work and the
JSR 219 specification, which is available at
http://www.jcp.org/en/jsr/detail?id=219, the latter takes precedence.
*/
package java.util;
/**
* Linked list implementation of the List interface. Implements all
* optional list operations, and permits all elements (including
* null). In addition to implementing the List interface,
* the LinkedList class provides uniformly named methods to
* get, remove and insert an element at the
* beginning and end of the list. These operations allow linked lists to be
* used as a stack, queue, or double-ended queue (deque).
*
* All of the stack/queue/deque operations could be easily recast in terms of
* the standard list operations. They're included here primarily for
* convenience, though they may run slightly faster than the equivalent List
* operations.
*
* 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 begining or the end, whichever is closer to the specified index.
*
* Note that this implementation is not synchronized. If multiple
* threads access a 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
* 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 the this class's iterator and
* 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 remove or add methods,
* the iterator will throw a 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 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
* @version 1.37, 03/12/05
* @see List
* @see ArrayList
* @see Vector
* @see Collections#synchronizedList(List)
* @since 1.2
*/
public class LinkedList extends AbstractSequentialList
implements List, Cloneable, java.io.Serializable
{
/**
* 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) { }
/**
* Returns the first element in this list.
*
* @return the first element in this list.
* @throws NoSuchElementException if this list is empty.
*/
public Object getFirst() {
return null;
}
/**
* Returns the last element in this list.
*
* @return the last element in this list.
* @throws NoSuchElementException if this list is empty.
*/
public Object getLast() {
return null;
}
/**
* Removes and returns the first element from this list.
*
* @return the first element from this list.
* @throws NoSuchElementException if this list is empty.
*/
public Object removeFirst() {
return null;
}
/**
* Removes and returns the last element from this list.
*
* @return the last element from this list.
* @throws NoSuchElementException if this list is empty.
*/
public Object removeLast() {
return null;
}
/**
* Inserts the given element at the beginning of this list.
*
* @param o the element to be inserted at the beginning of this list.
*/
public void addFirst(Object o) { }
/**
* Appends the given element to the end of this list. (Identical in
* function to the add method; included only for consistency.)
*
* @param o the element to be inserted at the end of this list.
*/
public void addLast(Object o) { }
/**
* Returns true if this list contains the specified element.
* More formally, returns true if and only if this list contains
* at least one element e such that (o==null ? e==null
* : o.equals(e)).
*
* @param o element whose presence in this list is to be tested.
* @return true if this list contains the specified element.
*/
public boolean contains(Object o) {
return false;
}
/**
* Returns the number of elements in this list.
*
* @return the number of elements in this list.
*/
public int size() {
return 0;
}
/**
* Appends the specified element to the end of this list.
*
* @param o element to be appended to this list.
* @return true (as per the general contract of
* Collection.add).
*/
public boolean add(Object o) {
return false;
}
/**
* Removes the first occurrence of the specified element in this list. If
* the list does not contain the element, it is unchanged. More formally,
* removes the element with the lowest index i such that
* (o==null ? get(i)==null : o.equals(get(i))) (if such an
* element exists).
*
* @param o element to be removed from this list, if present.
* @return true if the list contained the specified element.
*/
public boolean remove(Object o) {
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. (This implies that the behavior of this call is undefined if
* the specified Collection is this list, and this list is nonempty.)
*
* @param c the elements to be inserted into this list.
* @return 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 false;
}
/**
* 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 first element
* from the specified collection.
* @param c elements to be inserted into this list.
* @return true if this list changed as a result of the call.
* @throws IndexOutOfBoundsException if the specified index is out of
* range (index < 0 || index > size()).
* @throws NullPointerException if the specified collection is null.
*/
public boolean addAll(int index, Collection c) {
return false;
}
/**
* Removes all of the elements from this list.
*/
public void clear() { }
/**
* Returns the element at the specified position in this list.
*
* @param index index of element to return.
* @return the element at the specified position in this list.
*
* @throws IndexOutOfBoundsException if the specified index is is out of
* range (index < 0 || index >= size()).
*/
public Object get(int index) {
return null;
}
/**
* Replaces the element at the specified position in this list with the
* specified element.
*
* @param index index of element to replace.
* @param element element to be stored at the specified position.
* @return the element previously at the specified position.
* @throws IndexOutOfBoundsException if the specified index is out of
* range (index < 0 || index >= size()).
*/
public Object set(int index, Object element) {
return null;
}
/**
* 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 if the specified index is out of
* range (index < 0 || index > size()).
*/
public void add(int index, Object element) { }
/**
* 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 removed.
* @return the element previously at the specified position.
*
* @throws IndexOutOfBoundsException if the specified index is out of
* range (index < 0 || index >= size()).
*/
public Object remove(int index) {
return null;
}
/**
* Returns the index in this list of the first occurrence of the
* specified element, or -1 if the List does not contain this
* element. More formally, returns the lowest index 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 in this list of the first occurrence of the
* specified element, or -1 if the list does not contain this
* element.
*/
public int indexOf(Object o) {
return 0;
}
/**
* Returns the index in this list of the last occurrence of the
* specified element, or -1 if the list does not contain this
* element. More formally, returns the highest index 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 in this list of the last occurrence of the
* specified element, or -1 if the list does not contain this
* element.
*/
public int lastIndexOf(Object o) {
return 0;
}
/**
* 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 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 remove or add
* methods, the list-iterator will throw a
* 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 first element to be returned from the
* list-iterator (by a call to next).
* @return a ListIterator of the elements in this list (in proper
* sequence), starting at the specified position in the list.
* @throws IndexOutOfBoundsException if index is out of range
* (index < 0 || index > size()).
* @see List#listIterator(int)
*/
public ListIterator listIterator(int index) {
return null;
}
/**
* Returns a shallow copy of this LinkedList. (The elements
* themselves are not cloned.)
*
* @return a shallow copy of this LinkedList instance.
*/
public Object clone() {
return null;
}
/**
* Returns an array containing all of the elements in this list
* in the correct order.
*
* @return an array containing all of the elements in this list
* in the correct order.
*/
public Object[] toArray() {
return null;
}
/**
* Returns an array containing all of the elements in this list in
* the correct order; 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
* collection is set to 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.
*
* @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 a is not a
* supertype of the runtime type of every element in this list.
* @throws NullPointerException if the specified array is null.
*/
public Object[] toArray(Object[] a) {
return null;
}
/**
* Reconstitute this LinkedList instance from a stream (that is
* deserialize it).
*/
private void readObject(java.io.ObjectInputStream s)
throws java.io.IOException, ClassNotFoundException
{ }
/**
* Save the state of this LinkedList instance to a stream (that
* is, serialize it).
*
* @serialData The size of the list (the number of elements it
* contains) is emitted (int), followed by all of its
* elements (each an Object) in the proper order.
*/
private void writeObject(java.io.ObjectOutputStream s)
throws java.io.IOException
{ }
private static final long serialVersionUID = 876323262645176354L;
}