org.onemind.commons.java.lang.reflect
Class ClassLookupCache

java.lang.Object
  org.onemind.commons.java.datastructure.LookupCache
      org.onemind.commons.java.lang.reflect.ClassLookupCache

public class ClassLookupCache
extends LookupCache

A class lookup cache can lookup non-fully-qualified name classes for a given set of packages and will cache the lookup for later use. For example,

      ClassLookupCache cache = new ClassLookupCache();
      cache.addPackage("*"); //default package
      cache.addPackage("java.io.*");
  
      Class c = cache.getClass("File"); //c = java.io.File
      c = cache.getClass("File1"); //c = null
 

NOTE: 1. The cache is static for all instances of the lookup cache. 2. The packages is instance specific 3. It will cache only positive and negative response of fully qualified name thus lookup of non-fully-qualified has some performance hit, but for the sake of correctness

Version:

$Id: ClassLookupCache.java,v 1.6 2006/10/29 17:02:38 thlee Exp $ $Name: $

Author:

TiongHiang Lee (thlee@onemindsoft.org)

Field Summary

private static java.util.logging.Logger	_logger the logger *
private java.util.HashSet	_packages the packages *

Constructor Summary

ClassLookupCache()

Method Summary

void	addImport(java.lang.String importName) Add a new package.
protected void	clearNegCache() Clear all the negative cache
java.lang.Class	getClass(java.lang.String className) Get the class given by the fully-qualified or non-fully qualified java class name
java.util.Set	getPackages() Get all the import packages in this lookup cache.
protected boolean	isInCache(java.lang.Object o) Test if the key is in cache
protected boolean	isInNegCache(java.lang.Object o) Get whether the object is in negative cache
java.lang.Object	produce(java.lang.Object key) Produce the class given the key Produce the object given the key.
protected void	setDoNegativeCache(boolean b) Turn on/off the negative cache

Methods inherited from class org.onemind.commons.java.datastructure.LookupCache

lookup

Methods inherited from class java.lang.Object

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

Field Detail

_packages

private final java.util.HashSet _packages

the packages *

_logger

private static final java.util.logging.Logger _logger

the logger *

Constructor Detail

ClassLookupCache

public ClassLookupCache()

Method Detail

addImport

public void addImport(java.lang.String importName)

Add a new package.

Parameters:

packageName - the package name

getClass

public java.lang.Class getClass(java.lang.String className)

Get the class given by the fully-qualified or non-fully qualified java class name

Parameters:

className - the class name

Returns:

the class or null

produce

public java.lang.Object produce(java.lang.Object key)

Produce the class given the key Produce the object given the key. This is assumed to be an expensive operation and it will be called by the lookup method. The result will be cached by the lookup method and negative result also will be cached to if the doNegCache is turned on.

Specified by:

produce in class LookupCache

Parameters:

key - the key

Returns:

the result or null if no result

getPackages

public java.util.Set getPackages()

Get all the import packages in this lookup cache.

Returns:

the packages

clearNegCache

protected void clearNegCache()

Clear all the negative cache

Overrides:

clearNegCache in class LookupCache

isInCache

protected boolean isInCache(java.lang.Object o)

Test if the key is in cache

Overrides:

isInCache in class LookupCache

Parameters:

o - the object

Returns:

true if is in cache

isInNegCache

protected boolean isInNegCache(java.lang.Object o)

Get whether the object is in negative cache

Overrides:

isInNegCache in class LookupCache

Parameters:

o - the object

Returns:

true if is in negative cache

setDoNegativeCache

protected void setDoNegativeCache(boolean b)

Turn on/off the negative cache

Overrides:

setDoNegativeCache in class LookupCache

Parameters:

b - true to turn on the neg cache