org.apache.commons.collections

Class FactoryUtils


public class FactoryUtils
extends java.lang.Object

FactoryUtils provides reference implementations and utilities for the Factory functor interface. The supplied factories are: All the supplied factories are Serializable.
Version:
$Revision: 1.14 $ $Date: 2004/04/14 21:47:47 $
Author:
Stephen Colebourne
Since:
Commons Collections 3.0

Constructor Summary

FactoryUtils()
This class is not normally instantiated.

Method Summary

static Factory
constantFactory(Object constantToReturn)
Creates a Factory that will return the same object each time the factory is used.
static Factory
exceptionFactory()
Gets a Factory that always throws an exception.
static Factory
instantiateFactory(Class classToInstantiate)
Creates a Factory that can create objects of a specific type using a no-args constructor.
static Factory
instantiateFactory(Class classToInstantiate, Class[] paramTypes, Object[] args)
Creates a Factory that can create objects of a specific type using the arguments specified to this method.
static Factory
nullFactory()
Gets a Factory that will return null each time the factory is used.
static Factory
prototypeFactory(Object prototype)
Creates a Factory that will return a clone of the same prototype object each time the factory is used.

Constructor Details

FactoryUtils

public FactoryUtils()
This class is not normally instantiated.

Method Details

constantFactory

public static Factory constantFactory(Object constantToReturn)
Creates a Factory that will return the same object each time the factory is used. No check is made that the object is immutable. In general, only immutable objects should use the constant factory. Mutable objects should use the prototype factory.
Parameters:
constantToReturn - the constant object to return each time in the factory
Returns:
the constant factory.

exceptionFactory

public static Factory exceptionFactory()
Gets a Factory that always throws an exception. This could be useful during testing as a placeholder.
Returns:
the factory

instantiateFactory

public static Factory instantiateFactory(Class classToInstantiate)
Creates a Factory that can create objects of a specific type using a no-args constructor.
Parameters:
classToInstantiate - the Class to instantiate each time in the factory
Returns:
the reflection factory

instantiateFactory

public static Factory instantiateFactory(Class classToInstantiate,
                                         Class[] paramTypes,
                                         Object[] args)
Creates a Factory that can create objects of a specific type using the arguments specified to this method.
Parameters:
classToInstantiate - the Class to instantiate each time in the factory
paramTypes - parameter types for the constructor, can be null
args - the arguments to pass to the constructor, can be null
Returns:
the reflection factory

nullFactory

public static Factory nullFactory()
Gets a Factory that will return null each time the factory is used. This could be useful during testing as a placeholder.
Returns:
the factory

prototypeFactory

public static Factory prototypeFactory(Object prototype)
Creates a Factory that will return a clone of the same prototype object each time the factory is used. The prototype will be cloned using one of these techniques (in order):
  • public clone method
  • public copy constructor
  • serialization clone
    Parameters:
    prototype - the object to clone each time in the factory
    Returns:
    the prototype factory

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