net.sf.kdgcommons.lang

Class ClassTable<T>

java.lang.Object

net.sf.kdgcommons.lang.ClassTable<T>

public class ClassTable<T>
extends Object

A threadsafe Map<Class,T>, in which get(java.lang.Class<?>) will walk the class hiearchy of its argument looking for a mapping (and will cache that mapping for subsequent use). Primarily useful as a Method cache.

Warningput(java.lang.Class<?>, T) on a base set of classes, followed by calls to get(java.lang.Class<?>) with arbitrary descendents of those classes. Interspersed calls to get() and put() are discouraged, as they may leave different mappings for members of the same class hierarchy. If you need to replace a mapping, call replace(java.lang.Class<?>, T).

Constructor Summary

Constructors

Constructor and Description
ClassTable()

Method Summary

Modifier and Type	Method and Description
T	get(Class<?> klass) Returns the mapping corresponding to the passed class, traversing its concrete inheritance hierarchy until a match is found.
T	getByObject(Object obj) Returns the mapping corresponding to the passed object's class.
void	put(Class<?> klass, T object) Adds a mapping to the table, replacing any previous exact mapping for that class.
void	replace(Class<?> klass, T value) Replaces the mapping for the passed class and all known subclasses.
int	size() Returns the number of mappings in this object.

Methods inherited from class java.lang.Object

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

Constructor Detail

ClassTable

public ClassTable()

Method Detail

size

public int size()

Returns the number of mappings in this object. Useful for debugging/testing.

put

public void put(Class<?> klass,
                T object)

Adds a mapping to the table, replacing any previous exact mapping for that class. Subclass mappings are not affected.

get

public T get(Class<?> klass)

Returns the mapping corresponding to the passed class, traversing its concrete inheritance hierarchy until a match is found. Returns null if unable to find a match.

getByObject

public T getByObject(Object obj)

Returns the mapping corresponding to the passed object's class.

replace

public void replace(Class<?> klass,
                    T value)

Replaces the mapping for the passed class and all known subclasses. This is an atomic operation. Note, however, that concurrent threads may see either the old or new mapping.