Package com.thoughtworks.paranamer

Class CachingParanamer

java.lang.Object

com.thoughtworks.paranamer.CachingParanamer

All Implemented Interfaces:

Paranamer

Direct Known Subclasses:

CachingParanamer.WithoutWeakReferences

public class CachingParanamer
extends Object
implements Paranamer

Implementation of Paranamer which delegate to another Paranamer implementation, adding caching functionality to speed up usage. It also uses a WeakHashmap as an implementation detail (wrapped in Collections.synchronizedMap(..)), to allow large usages to garbage collect things as big as whole classloaders (after working through all the refs that originated from that classloader). Tomcat and other 'containers' do this during hot application deployment, undeployment and most importantly for Paranamer redeployment. Basically, this will allow a perm-gen usage keeps growing scenario.

Author:

Paul Hammant, Mauro Talevi

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	CachingParanamer.WithoutWeakReferences	This implementation has a better concurrent design (ConcurrentHashMap) which has a better strategy to implement concurrency: segments instead of synchronized.

Field Summary

Fields

Modifier and Type	Field	Description
static String	__PARANAMER_DATA

Fields inherited from interface com.thoughtworks.paranamer.Paranamer

EMPTY_NAMES

Constructor Summary

Constructors

Constructor	Description
CachingParanamer()	Uses a DefaultParanamer as the implementation it delegates to.
CachingParanamer(Paranamer delegate)	Specify a Paranamer instance to delegates to.

Method Summary

Modifier and Type	Method	Description
String[]	lookupParameterNames(AccessibleObject methodOrConstructor)	Lookup the parameter names of a given method.
String[]	lookupParameterNames(AccessibleObject methodOrCtor, boolean throwExceptionIfMissing)	Lookup the parameter names of a given method.
protected Map<AccessibleObject,String[]>	makeMethodCache()

Methods inherited from class java.lang.Object

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

Field Detail

__PARANAMER_DATA

public static final String __PARANAMER_DATA

See Also:

Constant Field Values

Constructor Detail

CachingParanamer

public CachingParanamer()

Uses a DefaultParanamer as the implementation it delegates to.

CachingParanamer

public CachingParanamer(Paranamer delegate)

Specify a Paranamer instance to delegates to.

Parameters:

delegate - the paranamer instance to use

Method Detail

makeMethodCache

protected Map<AccessibleObject,String[]> makeMethodCache()

lookupParameterNames

public String[] lookupParameterNames(AccessibleObject methodOrConstructor)

Description copied from interface: Paranamer

Lookup the parameter names of a given method.

Specified by:

lookupParameterNames in interface Paranamer

Parameters:

methodOrConstructor - the Method or Constructor for which the parameter names are looked up.

Returns:

A list of the parameter names.

lookupParameterNames

public String[] lookupParameterNames(AccessibleObject methodOrCtor,
                                     boolean throwExceptionIfMissing)

Description copied from interface: Paranamer

Lookup the parameter names of a given method.

Specified by:

lookupParameterNames in interface Paranamer

Parameters:

methodOrCtor - the Method or Constructor for which the parameter names are looked up.

throwExceptionIfMissing - whether to throw an exception if no Paranamer data found (versus return null).

Returns:

A list of the parameter names.