Package org.apache.commons.collections4.list

Class AbstractLinkedList<E>

java.lang.Object

org.apache.commons.collections4.list.AbstractLinkedList<E>

Type Parameters:

E - the type of elements in this list

All Implemented Interfaces:

Iterable<E>, Collection<E>, List<E>

Direct Known Subclasses:

CursorableLinkedList, NodeCachingLinkedList

public abstract class AbstractLinkedList<E>
extends Object
implements List<E>

An abstract implementation of a linked list which provides numerous points for subclasses to override.

Overridable methods are provided to change the storage node and to change how nodes are added to and removed. Hopefully, all you need for unusual subclasses is here.

Since:

3.0

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	AbstractLinkedList.LinkedListIterator<E>	A list iterator over the linked list.
protected static class	AbstractLinkedList.LinkedSubList<E>	The sublist implementation for AbstractLinkedList.
protected static class	AbstractLinkedList.LinkedSubListIterator<E>	A list iterator over the linked sub list.
protected static class	AbstractLinkedList.Node<E>	A node within the linked list.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractLinkedList()	Constructor that does nothing (intended for deserialization).
protected	AbstractLinkedList(Collection<? extends E> coll)	Constructs a list copying data from the specified collection.

Method Summary

Modifier and Type	Method	Description
void	add(int index, E value)
boolean	add(E value)
boolean	addAll(int index, Collection<? extends E> coll)
boolean	addAll(Collection<? extends E> coll)
boolean	addFirst(E o)
boolean	addLast(E o)
protected void	addNode(AbstractLinkedList.Node<E> nodeToInsert, AbstractLinkedList.Node<E> insertBeforeNode)	Inserts a new node into the list.
protected void	addNodeAfter(AbstractLinkedList.Node<E> node, E value)	Creates a new node with the specified object as its value and inserts it after node.
protected void	addNodeBefore(AbstractLinkedList.Node<E> node, E value)	Creates a new node with the specified object as its value and inserts it before node.
void	clear()
boolean	contains(Object value)
boolean	containsAll(Collection<?> coll)
protected AbstractLinkedList.Node<E>	createHeaderNode()	Creates a new node with previous, next and element all set to null.
protected AbstractLinkedList.Node<E>	createNode(E value)	Creates a new node with the specified properties.
protected Iterator<E>	createSubListIterator(AbstractLinkedList.LinkedSubList<E> subList)	Creates an iterator for the sublist.
protected ListIterator<E>	createSubListListIterator(AbstractLinkedList.LinkedSubList<E> subList, int fromIndex)	Creates a list iterator for the sublist.
protected void	doReadObject(ObjectInputStream inputStream)	Deserializes the data held in this object to the stream specified.
protected void	doWriteObject(ObjectOutputStream outputStream)	Serializes the data held in this object to the stream specified.
boolean	equals(Object obj)
E	get(int index)
E	getFirst()
E	getLast()
protected AbstractLinkedList.Node<E>	getNode(int index, boolean endMarkerAllowed)	Gets the node at a particular index.
int	hashCode()
int	indexOf(Object value)
protected void	init()	The equivalent of a default constructor, broken out so it can be called by any constructor and by readObject.
boolean	isEmpty()
protected boolean	isEqualValue(Object value1, Object value2)	Compares two values for equals.
Iterator<E>	iterator()
int	lastIndexOf(Object value)
ListIterator<E>	listIterator()
ListIterator<E>	listIterator(int fromIndex)
E	remove(int index)
boolean	remove(Object value)
boolean	removeAll(Collection<?> coll)
protected void	removeAllNodes()	Removes all nodes by resetting the circular list marker.
E	removeFirst()
E	removeLast()
protected void	removeNode(AbstractLinkedList.Node<E> node)	Removes the specified node from the list.
boolean	retainAll(Collection<?> coll)
E	set(int index, E value)
int	size()
List<E>	subList(int fromIndexInclusive, int toIndexExclusive)	Gets a sublist of the main list.
Object[]	toArray()
<T> T[]	toArray(T[] array)
String	toString()
protected void	updateNode(AbstractLinkedList.Node<E> node, E value)	Updates the node with a new value.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream

Methods inherited from interface java.lang.Iterable

forEach

Methods inherited from interface java.util.List

replaceAll, sort, spliterator

Constructor Details

AbstractLinkedList

protected AbstractLinkedList()

Constructor that does nothing (intended for deserialization).

If this constructor is used by a serializable subclass then the init() method must be called.

AbstractLinkedList

protected AbstractLinkedList(Collection<? extends E> coll)

Constructs a list copying data from the specified collection.

Parameters:

coll - the collection to copy

Method Details

add

public boolean add(E value)

Specified by:

add in interface Collection<E>

Specified by:

add in interface List<E>

add

public void add(int index,
 E value)

Specified by:

add in interface List<E>

addAll

public boolean addAll(Collection<? extends E> coll)

Specified by:

addAll in interface Collection<E>

Specified by:

addAll in interface List<E>

addAll

public boolean addAll(int index,
 Collection<? extends E> coll)

Specified by:

addAll in interface List<E>

addFirst

public boolean addFirst(E o)

addLast

public boolean addLast(E o)

addNode

protected void addNode(AbstractLinkedList.Node<E> nodeToInsert,
 AbstractLinkedList.Node<E> insertBeforeNode)

Inserts a new node into the list.

Parameters:

nodeToInsert - new node to insert

insertBeforeNode - node to insert before

Throws:

NullPointerException - if either node is null

addNodeAfter

protected void addNodeAfter(AbstractLinkedList.Node<E> node,
 E value)

Creates a new node with the specified object as its value and inserts it after node.

This implementation uses createNode(Object) and addNode(AbstractLinkedList.Node,AbstractLinkedList.Node).

Parameters:

node - node to insert after

value - value of the newly added node

Throws:

NullPointerException - if node is null

addNodeBefore

protected void addNodeBefore(AbstractLinkedList.Node<E> node,
 E value)

Creates a new node with the specified object as its value and inserts it before node.

This implementation uses createNode(Object) and addNode(AbstractLinkedList.Node,AbstractLinkedList.Node).

Parameters:

node - node to insert before

value - value of the newly added node

Throws:

NullPointerException - if node is null

clear

public void clear()

Specified by:

clear in interface Collection<E>

Specified by:

clear in interface List<E>

contains

public boolean contains(Object value)

Specified by:

contains in interface Collection<E>

Specified by:

contains in interface List<E>

containsAll

public boolean containsAll(Collection<?> coll)

Specified by:

containsAll in interface Collection<E>

Specified by:

containsAll in interface List<E>

createHeaderNode

protected AbstractLinkedList.Node<E> createHeaderNode()

Creates a new node with previous, next and element all set to null. This implementation creates a new empty Node. Subclasses can override this to create a different class.

Returns:

newly created node

createNode

protected AbstractLinkedList.Node<E> createNode(E value)

Creates a new node with the specified properties. This implementation creates a new Node with data. Subclasses can override this to create a different class.

Parameters:

value - value of the new node

Returns:

a new node containing the value

createSubListIterator

protected Iterator<E> createSubListIterator(AbstractLinkedList.LinkedSubList<E> subList)

Creates an iterator for the sublist.

Parameters:

subList - the sublist to get an iterator for

Returns:

a new iterator on the given sublist

createSubListListIterator

protected ListIterator<E> createSubListListIterator(AbstractLinkedList.LinkedSubList<E> subList,
 int fromIndex)

Creates a list iterator for the sublist.

Parameters:

subList - the sublist to get an iterator for

fromIndex - the index to start from, relative to the sublist

Returns:

a new list iterator on the given sublist

doReadObject

protected void doReadObject(ObjectInputStream inputStream)
                     throws IOException,
ClassNotFoundException

Deserializes the data held in this object to the stream specified.

The first serializable subclass must call this method from readObject.

Parameters:

inputStream - the stream to read the object from

Throws:

IOException - if any error occurs while reading from the stream

ClassNotFoundException - if a class read from the stream can not be loaded

doWriteObject

protected void doWriteObject(ObjectOutputStream outputStream)
                      throws IOException

Serializes the data held in this object to the stream specified.

The first serializable subclass must call this method from writeObject.

Parameters:

outputStream - the stream to write the object to

Throws:

IOException - if anything goes wrong

equals

public boolean equals(Object obj)

Specified by:

equals in interface Collection<E>

Specified by:

equals in interface List<E>

Overrides:

equals in class Object

get

public E get(int index)

Specified by:

get in interface List<E>

getFirst

public E getFirst()

getLast

public E getLast()

getNode

protected AbstractLinkedList.Node<E> getNode(int index,
 boolean endMarkerAllowed)
                                      throws IndexOutOfBoundsException

Gets the node at a particular index.

Parameters:

index - the index, starting from 0

endMarkerAllowed - whether or not the end marker can be returned if startIndex is set to the list's size

Returns:

the node at the given index

Throws:

IndexOutOfBoundsException - if the index is less than 0; equal to the size of the list and endMakerAllowed is false; or greater than the size of the list

hashCode

public int hashCode()

Specified by:

hashCode in interface Collection<E>

Specified by:

hashCode in interface List<E>

Overrides:

hashCode in class Object

indexOf

public int indexOf(Object value)

Specified by:

indexOf in interface List<E>

init

protected void init()

The equivalent of a default constructor, broken out so it can be called by any constructor and by readObject. Subclasses which override this method should make sure they call super, so the list is initialized properly.

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Collection<E>

Specified by:

isEmpty in interface List<E>

isEqualValue

protected boolean isEqualValue(Object value1,
 Object value2)

Compares two values for equals. This implementation uses the equals method. Subclasses can override this to match differently.

Parameters:

value1 - the first value to compare, may be null

value2 - the second value to compare, may be null

Returns:

true if equal

iterator

public Iterator<E> iterator()

Specified by:

iterator in interface Collection<E>

Specified by:

iterator in interface Iterable<E>

Specified by:

iterator in interface List<E>

lastIndexOf

public int lastIndexOf(Object value)

Specified by:

lastIndexOf in interface List<E>

listIterator

public ListIterator<E> listIterator()

Specified by:

listIterator in interface List<E>

listIterator

public ListIterator<E> listIterator(int fromIndex)

Specified by:

listIterator in interface List<E>

remove

public E remove(int index)

Specified by:

remove in interface List<E>

remove

public boolean remove(Object value)

Specified by:

remove in interface Collection<E>

Specified by:

remove in interface List<E>

removeAll

public boolean removeAll(Collection<?> coll)

This implementation iterates over the elements of this list, checking each element in turn to see if it's contained in coll. If it's contained, it's removed from this list. As a consequence, it is advised to use a collection type for coll that provides a fast (e.g. O(1)) implementation of Collection.contains(Object).

Specified by:

removeAll in interface Collection<E>

Specified by:

removeAll in interface List<E>

removeAllNodes

protected void removeAllNodes()

Removes all nodes by resetting the circular list marker.

removeFirst

public E removeFirst()

removeLast

public E removeLast()

removeNode

protected void removeNode(AbstractLinkedList.Node<E> node)

Removes the specified node from the list.

Parameters:

node - the node to remove

Throws:

NullPointerException - if node is null

retainAll

public boolean retainAll(Collection<?> coll)

This implementation iterates over the elements of this list, checking each element in turn to see if it's contained in coll. If it's not contained, it's removed from this list. As a consequence, it is advised to use a collection type for coll that provides a fast (e.g. O(1)) implementation of Collection.contains(Object).

Specified by:

retainAll in interface Collection<E>

Specified by:

retainAll in interface List<E>

set

public E set(int index,
 E value)

Specified by:

set in interface List<E>

size

public int size()

Specified by:

size in interface Collection<E>

Specified by:

size in interface List<E>

subList

public List<E> subList(int fromIndexInclusive,
 int toIndexExclusive)

Gets a sublist of the main list.

Specified by:

subList in interface List<E>

Parameters:

fromIndexInclusive - the index to start from

toIndexExclusive - the index to end at

Returns:

the new sublist

toArray

public Object[] toArray()

Specified by:

toArray in interface Collection<E>

Specified by:

toArray in interface List<E>

toArray

public <T> T[] toArray(T[] array)

Specified by:

toArray in interface Collection<E>

Specified by:

toArray in interface List<E>

toString

public String toString()

Overrides:

toString in class Object

updateNode

protected void updateNode(AbstractLinkedList.Node<E> node,
 E value)

Updates the node with a new value. This implementation sets the value on the node. Subclasses can override this to record the change.

Parameters:

node - node to update

value - new value of the node