org.apache.commons.configuration2.beanutils

Class DefaultBeanFactory

java.lang.Object

org.apache.commons.configuration2.beanutils.DefaultBeanFactory

All Implemented Interfaces:

BeanFactory

public class DefaultBeanFactory
extends Object
implements BeanFactory

The default implementation of the BeanFactory interface.

This class creates beans of arbitrary types using reflection. Each time the createBean() method is invoked, a new bean instance is created. A default bean class is not supported.

For data type conversions (which may be needed before invoking methods through reflection to ensure that the current parameters match their declared types) a ConversionHandler object is used. An instance of this class can be passed to the constructor. Alternatively, a default ConversionHandler instance is used.

An instance of this factory class will be set as the default bean factory for the BeanHelper class. This means that if not bean factory is specified in a BeanDeclaration, this default instance will be used.

Since:

1.3

Field Summary

Fields

Modifier and Type	Field and Description
static DefaultBeanFactory	INSTANCE Stores the default instance of this class.

Constructor Summary

Constructors

Constructor and Description
DefaultBeanFactory() Creates a new instance of DefaultBeanFactory using a default ConversionHandler.
DefaultBeanFactory(ConversionHandler convHandler) Creates a new instance of DefaultBeanFactory using the specified ConversionHandler for data type conversions.

Method Summary

Modifier and Type	Method and Description
Object	createBean(BeanCreationContext bcc) Creates a new bean instance.
protected Object	createBeanInstance(BeanCreationContext bcc) Creates the bean instance.
protected static <T> Constructor<T>	findMatchingConstructor(Class<T> beanClass, BeanDeclaration data) Evaluates constructor arguments in the specified BeanDeclaration and tries to find a unique matching constructor.
ConversionHandler	getConversionHandler() Returns the ConversionHandler used by this object.
Class<?>	getDefaultBeanClass() Returns the default bean class used by this factory.
protected void	initBeanInstance(Object bean, BeanCreationContext bcc) Initializes the newly created bean instance.

Methods inherited from class java.lang.Object

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

Field Detail

INSTANCE

public static final DefaultBeanFactory INSTANCE

Stores the default instance of this class.

Constructor Detail

DefaultBeanFactory

public DefaultBeanFactory()

Creates a new instance of DefaultBeanFactory using a default ConversionHandler.

DefaultBeanFactory

public DefaultBeanFactory(ConversionHandler convHandler)

Creates a new instance of DefaultBeanFactory using the specified ConversionHandler for data type conversions.

Parameters:

convHandler - the ConversionHandler; can be null, then a default handler is used

Since:

2.0

Method Detail

getConversionHandler

public ConversionHandler getConversionHandler()

Returns the ConversionHandler used by this object.

Returns:

the ConversionHandler

Since:

2.0

createBean

public Object createBean(BeanCreationContext bcc)
                  throws Exception

Creates a new bean instance. This implementation delegates to the protected methods createBeanInstance() and initBeanInstance() for creating and initializing the bean. This makes it easier for derived classes that need to change specific functionality of the base class.

Specified by:

createBean in interface BeanFactory

Parameters:

bcc - the context object defining the bean to be created

Returns:

the new bean instance

Throws:

Exception - if an error occurs

getDefaultBeanClass

public Class<?> getDefaultBeanClass()

Returns the default bean class used by this factory. This is always null for this implementation.

Specified by:

getDefaultBeanClass in interface BeanFactory

Returns:

the default bean class

createBeanInstance

protected Object createBeanInstance(BeanCreationContext bcc)
                             throws Exception

Creates the bean instance. This method is called by createBean(). It uses reflection to create a new instance of the specified class.

Parameters:

bcc - the context object defining the bean to be created

Returns:

the new bean instance

Throws:

Exception - if an error occurs

initBeanInstance

protected void initBeanInstance(Object bean,
                                BeanCreationContext bcc)
                         throws Exception

Initializes the newly created bean instance. This method is called by createBean(). It calls the initBean() method of the context object for performing the initialization.

Parameters:

bean - the newly created bean instance

bcc - the context object defining the bean to be created

Throws:

Exception - if an error occurs

findMatchingConstructor

protected static <T> Constructor<T> findMatchingConstructor(Class<T> beanClass,
                                                            BeanDeclaration data)

Evaluates constructor arguments in the specified BeanDeclaration and tries to find a unique matching constructor. If this is not possible, an exception is thrown. Note: This method is intended to be used by concrete BeanFactory implementations and not by client code.

Type Parameters:

T - the type of the bean to be created

Parameters:

beanClass - the class of the bean to be created

data - the current BeanDeclaration

Returns:

the single matching constructor

Throws:

ConfigurationRuntimeException - if no single matching constructor can be found

NullPointerException - if the bean class or bean declaration are null