org.apache.commons.collections.list
Class AbstractLinkedList

java.lang.Object
  extended byorg.apache.commons.collections.list.AbstractLinkedList
All Implemented Interfaces:
Collection, List
Direct Known Subclasses:
CursorableLinkedList, NodeCachingLinkedList

public abstract class AbstractLinkedList
extends Object
implements List

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:
Commons Collections 3.0
Version:
$Revision: 1.9 $ $Date: 2004/04/20 23:33:54 $
Author:
Rich Dougherty, Phil Steitz, Stephen Colebourne

Nested Class Summary
protected static class AbstractLinkedList.LinkedListIterator
          A list iterator over the linked list.
protected static class AbstractLinkedList.LinkedSubList
          The sublist implementation for AbstractLinkedList.
protected static class AbstractLinkedList.LinkedSubListIterator
          A list iterator over the linked sub list.
protected static class AbstractLinkedList.Node
          A node within the linked list.
 
Field Summary
protected  AbstractLinkedList.Node header
          A AbstractLinkedList.Node which indicates the start and end of the list and does not hold a value.
protected  int modCount
          Modification count for iterators
protected  int size
          The size of the list
 
Constructor Summary
protected AbstractLinkedList()
          Constructor that does nothing intended for deserialization.
protected AbstractLinkedList(Collection coll)
          Constructs a list copying data from the specified collection.
 
Method Summary
 void add(int index, Object value)
           
 boolean add(Object value)
           
 boolean addAll(Collection coll)
           
 boolean addAll(int index, Collection coll)
           
 boolean addFirst(Object o)
           
 boolean addLast(Object o)
           
protected  void addNode(AbstractLinkedList.Node nodeToInsert, AbstractLinkedList.Node insertBeforeNode)
          Inserts a new node into the list.
protected  void addNodeAfter(AbstractLinkedList.Node node, Object value)
          Creates a new node with the specified object as its value and inserts it after node.
protected  void addNodeBefore(AbstractLinkedList.Node node, Object 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 createHeaderNode()
          Creates a new node with previous, next and element all set to null.
protected  AbstractLinkedList.Node createNode(Object value)
          Creates a new node with the specified properties.
protected  Iterator createSubListIterator(AbstractLinkedList.LinkedSubList subList)
          Creates an iterator for the sublist.
protected  ListIterator createSubListListIterator(AbstractLinkedList.LinkedSubList 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)
           
 Object get(int index)
           
 Object getFirst()
           
 Object getLast()
           
protected  AbstractLinkedList.Node 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 iterator()
           
 int lastIndexOf(Object value)
           
 ListIterator listIterator()
           
 ListIterator listIterator(int fromIndex)
           
 Object remove(int index)
           
 boolean remove(Object value)
           
 boolean removeAll(Collection coll)
           
protected  void removeAllNodes()
          Removes all nodes by resetting the circular list marker.
 Object removeFirst()
           
 Object removeLast()
           
protected  void removeNode(AbstractLinkedList.Node node)
          Removes the specified node from the list.
 boolean retainAll(Collection coll)
           
 Object set(int index, Object value)
           
 int size()
           
 List subList(int fromIndexInclusive, int toIndexExclusive)
          Gets a sublist of the main list.
 Object[] toArray()
           
 Object[] toArray(Object[] array)
           
 String toString()
           
protected  void updateNode(AbstractLinkedList.Node node, Object value)
          Updates the node with a new value.
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

header

protected transient AbstractLinkedList.Node header
A AbstractLinkedList.Node which indicates the start and end of the list and does not hold a value. The value of next is the first item in the list. The value of of previous is the last item in the list.


size

protected transient int size
The size of the list


modCount

protected transient int modCount
Modification count for iterators

Constructor Detail

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 coll)
Constructs a list copying data from the specified collection.

Parameters:
coll - the collection to copy
Method Detail

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 initialised properly.


size

public int size()
Specified by:
size in interface List

isEmpty

public boolean isEmpty()
Specified by:
isEmpty in interface List

get

public Object get(int index)
Specified by:
get in interface List

iterator

public Iterator iterator()
Specified by:
iterator in interface List

listIterator

public ListIterator listIterator()
Specified by:
listIterator in interface List

listIterator

public ListIterator listIterator(int fromIndex)
Specified by:
listIterator in interface List

indexOf

public int indexOf(Object value)
Specified by:
indexOf in interface List

lastIndexOf

public int lastIndexOf(Object value)
Specified by:
lastIndexOf in interface List

contains

public boolean contains(Object value)
Specified by:
contains in interface List

containsAll

public boolean containsAll(Collection coll)
Specified by:
containsAll in interface List

toArray

public Object[] toArray()
Specified by:
toArray in interface List

toArray

public Object[] toArray(Object[] array)
Specified by:
toArray in interface List

subList

public List subList(int fromIndexInclusive,
                    int toIndexExclusive)
Gets a sublist of the main list.

Specified by:
subList in interface List
Parameters:
fromIndexInclusive - the index to start from
toIndexExclusive - the index to end at
Returns:
the new sublist

add

public boolean add(Object value)
Specified by:
add in interface List

add

public void add(int index,
                Object value)
Specified by:
add in interface List

addAll

public boolean addAll(Collection coll)
Specified by:
addAll in interface List

addAll

public boolean addAll(int index,
                      Collection coll)
Specified by:
addAll in interface List

remove

public Object remove(int index)
Specified by:
remove in interface List

remove

public boolean remove(Object value)
Specified by:
remove in interface List

removeAll

public boolean removeAll(Collection coll)
Specified by:
removeAll in interface List

retainAll

public boolean retainAll(Collection coll)
Specified by:
retainAll in interface List

set

public Object set(int index,
                  Object value)
Specified by:
set in interface List

clear

public void clear()
Specified by:
clear in interface List

getFirst

public Object getFirst()

getLast

public Object getLast()

addFirst

public boolean addFirst(Object o)

addLast

public boolean addLast(Object o)

removeFirst

public Object removeFirst()

removeLast

public Object removeLast()

equals

public boolean equals(Object obj)
Specified by:
equals in interface List

hashCode

public int hashCode()
Specified by:
hashCode in interface List

toString

public String toString()

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

updateNode

protected void updateNode(AbstractLinkedList.Node node,
                          Object 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

createHeaderNode

protected AbstractLinkedList.Node 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 createNode(Object 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

addNodeBefore

protected void addNodeBefore(AbstractLinkedList.Node node,
                             Object 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

addNodeAfter

protected void addNodeAfter(AbstractLinkedList.Node node,
                            Object 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

addNode

protected void addNode(AbstractLinkedList.Node nodeToInsert,
                       AbstractLinkedList.Node 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

removeNode

protected void removeNode(AbstractLinkedList.Node node)
Removes the specified node from the list.

Parameters:
node - the node to remove
Throws:
NullPointerException - if node is null

removeAllNodes

protected void removeAllNodes()
Removes all nodes by resetting the circular list marker.


getNode

protected AbstractLinkedList.Node 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
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

createSubListIterator

protected Iterator createSubListIterator(AbstractLinkedList.LinkedSubList subList)
Creates an iterator for the sublist.

Parameters:
subList - the sublist to get an iterator for

createSubListListIterator

protected ListIterator createSubListListIterator(AbstractLinkedList.LinkedSubList 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

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.

Throws:
IOException

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.

Throws:
IOException
ClassNotFoundException


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