org.modeshape.jcr.cache

Class SiblingCounter

java.lang.Object

org.modeshape.jcr.cache.SiblingCounter

public abstract class SiblingCounter
extends Object

A function interface that determines (potentially lazily) the number of siblings with a given name.

Constructor Summary

Constructors

Constructor and Description
SiblingCounter()

Method Summary

Methods

Modifier and Type	Method and Description
static SiblingCounter	alter(SiblingCounter counter, int delta) Creates a sibling counter that alters another counter by a constant value.
static SiblingCounter	constant(int count) Create a sibling counter that always return the supplied count, regardless of the name or node.
abstract int	countSiblingsNamed(Name childName) Get the number of existing siblings that all have the supplied name.
static SiblingCounter	create(CachedNode node, NodeCache cache) Creates a sibling counter that lazily obtains a ChildReferences.
static SiblingCounter	create(ChildReferences childRefs) Creates a sibling counter that uses the supplied ChildReferences.
static SiblingCounter	noSiblings() Create a sibling counter that always returns '0' for the number of same name siblings.
static SiblingCounter	oneSibling() Create a sibling counter that always returns '1' for the number of same name siblings.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SiblingCounter

public SiblingCounter()

Method Detail

countSiblingsNamed

public abstract int countSiblingsNamed(Name childName)

Get the number of existing siblings that all have the supplied name. If the implementation is expensive, it should cache the result so subsequent calls with the same parameter are fast.

Parameters:

childName - the name for the siblings; may not be null

Returns:

the number of existing siblings with the new child's name

noSiblings

public static SiblingCounter noSiblings()

Create a sibling counter that always returns '0' for the number of same name siblings.

Returns:

the counter that always returns 0; never null

oneSibling

public static SiblingCounter oneSibling()

Create a sibling counter that always returns '1' for the number of same name siblings.

Returns:

the counter that always returns 0; never null

constant

public static SiblingCounter constant(int count)

Create a sibling counter that always return the supplied count, regardless of the name or node.

Parameters:

count - the count to be returned; may not be negative

Returns:

the counter that always returns count; never null

create

public static SiblingCounter create(ChildReferences childRefs)

Creates a sibling counter that uses the supplied ChildReferences.

Parameters:

childRefs - the child references; may not be null

Returns:

the sibling counter; never null

create

public static SiblingCounter create(CachedNode node,
                    NodeCache cache)

Creates a sibling counter that lazily obtains a ChildReferences.

Parameters:

node - the node; may not be null

cache - the cache; may not be null

Returns:

the sibling counter; never null

alter

public static SiblingCounter alter(SiblingCounter counter,
                   int delta)

Creates a sibling counter that alters another counter by a constant value.

Parameters:

counter - the sibling counter; may not be null

delta - the positive or negative amount by which the counter's value is altered

Returns:

the sibling counter; never null