NodeCachingLinkedList (Apache Commons Collections 3.2.2 API)

java.lang.Object
- org.apache.commons.collections.list.AbstractLinkedList
- - org.apache.commons.collections.list.NodeCachingLinkedList

All Implemented Interfaces:

Serializable, Iterable, Collection, List
```
public class NodeCachingLinkedList
extends AbstractLinkedList
implements Serializable
```
A List implementation that stores a cache of internal Node objects in an effort to reduce wasteful object creation.
A linked list creates one Node for each item of data added. This can result in a lot of object creation and garbage collection. This implementation seeks to avoid that by maintaining a store of cached nodes.
This implementation is suitable for long-lived lists where both add and remove are used. Short-lived lists, or lists which only grow will have worse performance using this class.
Note that this implementation is not synchronized.

Since:

Commons Collections 3.0

Version:

$Revision: 972404 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $

Author:

Jeff Varszegi, Rich Dougherty, Phil Steitz, Stephen Colebourne

See Also:
Serialized Form

Nested Class Summary
- Nested classes/interfaces inherited from class org.apache.commons.collections.list.AbstractLinkedList
  AbstractLinkedList.LinkedListIterator, AbstractLinkedList.LinkedSubList, AbstractLinkedList.LinkedSubListIterator, AbstractLinkedList.Node

Field Summary

Fields
Modifier and Type	Field and Description
`protected int`	`cacheSize` The size of the cache.
`protected static int`	`DEFAULT_MAXIMUM_CACHE_SIZE` The default value for `maximumCacheSize`.
`protected AbstractLinkedList.Node`	`firstCachedNode` The first cached node, or `null` if no nodes are cached.
`protected int`	`maximumCacheSize` The maximum size of the cache.

Fields inherited from class org.apache.commons.collections.list.AbstractLinkedList
header, modCount, size

Constructor Summary

Constructors
Constructor and Description
`NodeCachingLinkedList()` Constructor that creates.
`NodeCachingLinkedList(Collection coll)` Constructor that copies the specified collection
`NodeCachingLinkedList(int maximumCacheSize)` Constructor that species the maximum cache size.

Method Summary

Methods
Modifier and Type	Method and Description
`protected void`	`addNodeToCache(AbstractLinkedList.Node node)` Adds a node to the cache, if the cache isn't full.
`protected AbstractLinkedList.Node`	`createNode(Object value)` Creates a new node, either by reusing one from the cache or creating a new one.
`protected int`	`getMaximumCacheSize()` Gets the maximum size of the cache.
`protected AbstractLinkedList.Node`	`getNodeFromCache()` Gets a node from the cache.
`protected boolean`	`isCacheFull()` Checks whether the cache is full.
`protected void`	`removeAllNodes()` Removes all the nodes from the list, storing as many as required in the cache for reuse.
`protected void`	`removeNode(AbstractLinkedList.Node node)` Removes the node from the list, storing it in the cache for reuse if the cache is not yet full.
`protected void`	`setMaximumCacheSize(int maximumCacheSize)` Sets the maximum size of the cache.
`protected void`	`shrinkCacheToMaximumSize()` Reduce the size of the cache to the maximum, if necessary.

Methods inherited from class org.apache.commons.collections.list.AbstractLinkedList
add, add, addAll, addAll, addFirst, addLast, addNode, addNodeAfter, addNodeBefore, clear, contains, containsAll, createHeaderNode, createSubListIterator, createSubListListIterator, doReadObject, doWriteObject, equals, get, getFirst, getLast, getNode, hashCode, indexOf, init, isEmpty, isEqualValue, iterator, lastIndexOf, listIterator, listIterator, remove, remove, removeAll, removeFirst, removeLast, retainAll, set, size, subList, toArray, toArray, toString, updateNode

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - DEFAULT_MAXIMUM_CACHE_SIZE
```
protected static final int DEFAULT_MAXIMUM_CACHE_SIZE
```
    The default value for maximumCacheSize.
    
    See Also:
    Constant Field Values
  - firstCachedNode
```
protected transient AbstractLinkedList.Node firstCachedNode
```
    The first cached node, or null if no nodes are cached. Cached nodes are stored in a singly-linked list with next pointing to the next element.
  - cacheSize
```
protected transient int cacheSize
```
    The size of the cache.
  - maximumCacheSize
```
protected int maximumCacheSize
```
    The maximum size of the cache.
- Constructor Detail
  - NodeCachingLinkedList
```
public NodeCachingLinkedList()
```
    Constructor that creates.
  - NodeCachingLinkedList
```
public NodeCachingLinkedList(Collection coll)
```
    Constructor that copies the specified collection
    
    Parameters:
    coll - the collection to copy
  - NodeCachingLinkedList
```
public NodeCachingLinkedList(int maximumCacheSize)
```
    Constructor that species the maximum cache size.
    
    Parameters:
    maximumCacheSize - the maximum cache size
- Method Detail
  - getMaximumCacheSize
```
protected int getMaximumCacheSize()
```
    Gets the maximum size of the cache.
    
    Returns:
    the maximum cache size
  - setMaximumCacheSize
```
protected void setMaximumCacheSize(int maximumCacheSize)
```
    Sets the maximum size of the cache.
    
    Parameters:
    maximumCacheSize - the new maximum cache size
  - shrinkCacheToMaximumSize
```
protected void shrinkCacheToMaximumSize()
```
    Reduce the size of the cache to the maximum, if necessary.
  - getNodeFromCache
```
protected AbstractLinkedList.Node getNodeFromCache()
```
    Gets a node from the cache. If a node is returned, then the value of cacheSize is decreased accordingly. The node that is returned will have null values for next, previous and element.
    
    Returns:
    a node, or null if there are no nodes in the cache.
  - isCacheFull
```
protected boolean isCacheFull()
```
    Checks whether the cache is full.
    
    Returns:
    true if the cache is full
  - addNodeToCache
```
protected void addNodeToCache(AbstractLinkedList.Node node)
```
    Adds a node to the cache, if the cache isn't full. The node's contents are cleared to so they can be garbage collected.
    
    Parameters:
    node - the node to add to the cache
  - createNode
```
protected AbstractLinkedList.Node createNode(Object value)
```
    Creates a new node, either by reusing one from the cache or creating a new one.
    
    Overrides:
    
    createNode in class AbstractLinkedList
    
    Parameters:
    value - value of the new node
    
    Returns:
    the newly created node
  - removeNode
```
protected void removeNode(AbstractLinkedList.Node node)
```
    Removes the node from the list, storing it in the cache for reuse if the cache is not yet full.
    
    Overrides:
    
    removeNode in class AbstractLinkedList
    
    Parameters:
    node - the node to remove
  - removeAllNodes
```
protected void removeAllNodes()
```
    Removes all the nodes from the list, storing as many as required in the cache for reuse.
    
    Overrides:
    
    removeAllNodes in class AbstractLinkedList

Class NodeCachingLinkedList

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.commons.collections.list.AbstractLinkedList

Field Summary

Fields inherited from class org.apache.commons.collections.list.AbstractLinkedList

Constructor Summary

Method Summary

Methods inherited from class org.apache.commons.collections.list.AbstractLinkedList

Methods inherited from class java.lang.Object

Field Detail

DEFAULT_MAXIMUM_CACHE_SIZE

firstCachedNode

cacheSize

maximumCacheSize

Constructor Detail

NodeCachingLinkedList

NodeCachingLinkedList

NodeCachingLinkedList

Method Detail

getMaximumCacheSize

setMaximumCacheSize

shrinkCacheToMaximumSize

getNodeFromCache

isCacheFull

addNodeToCache

createNode

removeNode

removeAllNodes