BeanHelper (Apache Commons Configuration 1.10 API)

java.lang.Object
- org.apache.commons.configuration.beanutils.BeanHelper

```
public final class BeanHelper
extends Object
```
A helper class for creating bean instances that are defined in configuration files.

This class provides static utility methods related to bean creation operations. These methods simplify such operations because a client need not deal with all involved interfaces. Usually, if a bean declaration has already been obtained, a single method call is necessary to create a new bean instance.

This class also supports the registration of custom bean factories. Implementations of the BeanFactory interface can be registered under a symbolic name using the registerBeanFactory() method. In the configuration file the name of the bean factory can be specified in the bean declaration. Then this factory will be used to create the bean.

Since:

1.3

Version:

$Id: BeanHelper.java 1534393 2013-10-21 22:02:27Z henning $

Author:

Commons Configuration team

Method Summary

Methods
Modifier and Type	Method and Description
`static Object`	`createBean(BeanDeclaration data)` Returns a bean instance for the specified declaration.
`static Object`	`createBean(BeanDeclaration data, Class<?> defaultClass)` Returns a bean instance for the specified declaration.
`static Object`	`createBean(BeanDeclaration data, Class<?> defaultClass, Object param)` The main method for creating and initializing beans from a configuration.
`static BeanFactory`	`deregisterBeanFactory(String name)` Deregisters the bean factory with the given name.
`static BeanFactory`	`getDefaultBeanFactory()` Returns the default bean factory.
`static void`	`initBean(Object bean, BeanDeclaration data)` Initializes the passed in bean.
`static void`	`initBeanProperties(Object bean, BeanDeclaration data)` Initializes the beans properties.
`static void`	`registerBeanFactory(String name, BeanFactory factory)` Register a bean factory under a symbolic name.
`static Set<String>`	`registeredFactoryNames()` Returns a set with the names of all currently registered bean factories.
`static void`	`setDefaultBeanFactory(BeanFactory factory)` Sets the default bean factory.
`static void`	`setProperty(Object bean, String propName, Object value)` Set a property on the bean only if the property exists

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - registerBeanFactory
```
public static void registerBeanFactory(String name,
                       BeanFactory factory)
```
    Register a bean factory under a symbolic name. This factory object can then be specified in bean declarations with the effect that this factory will be used to obtain an instance for the corresponding bean declaration.
    
    Parameters:
    name - the name of the factory
    factory - the factory to be registered
  - deregisterBeanFactory
```
public static BeanFactory deregisterBeanFactory(String name)
```
    Deregisters the bean factory with the given name. After that this factory cannot be used any longer.
    
    Parameters:
    name - the name of the factory to be deregistered
    
    Returns:
    the factory that was registered under this name; null if there was no such factory
  - registeredFactoryNames
```
public static Set<String> registeredFactoryNames()
```
    Returns a set with the names of all currently registered bean factories.
    
    Returns:
    a set with the names of the registered bean factories
  - getDefaultBeanFactory
```
public static BeanFactory getDefaultBeanFactory()
```
    Returns the default bean factory.
    
    Returns:
    the default bean factory
  - setDefaultBeanFactory
```
public static void setDefaultBeanFactory(BeanFactory factory)
```
    Sets the default bean factory. This factory will be used for all create operations, for which no special factory is provided in the bean declaration.
    
    Parameters:
    factory - the default bean factory (must not be null)
  - initBean
```
public static void initBean(Object bean,
            BeanDeclaration data)
                     throws ConfigurationRuntimeException
```
    Initializes the passed in bean. This method will obtain all the bean's properties that are defined in the passed in bean declaration. These properties will be set on the bean. If necessary, further beans will be created recursively.
    
    Parameters:
    bean - the bean to be initialized
    data - the bean declaration
    
    Throws:
    
    ConfigurationRuntimeException - if a property cannot be set
  - initBeanProperties
```
public static void initBeanProperties(Object bean,
                      BeanDeclaration data)
                               throws ConfigurationRuntimeException
```
    Initializes the beans properties.
    
    Parameters:
    bean - the bean to be initialized
    data - the bean declaration
    
    Throws:
    
    ConfigurationRuntimeException - if a property cannot be set
  - setProperty
```
public static void setProperty(Object bean,
               String propName,
               Object value)
```
    Set a property on the bean only if the property exists
    
    Parameters:
    bean - the bean
    propName - the name of the property
    value - the property's value
    
    Throws:
    
    ConfigurationRuntimeException - if the property is not writeable or an error occurred
  - createBean
```
public static Object createBean(BeanDeclaration data,
                Class<?> defaultClass,
                Object param)
                         throws ConfigurationRuntimeException
```
    The main method for creating and initializing beans from a configuration. This method will return an initialized instance of the bean class specified in the passed in bean declaration. If this declaration does not contain the class of the bean, the passed in default class will be used. From the bean declaration the factory to be used for creating the bean is queried. The declaration may here return null, then a default factory is used. This factory is then invoked to perform the create operation.
    
    Parameters:
    data - the bean declaration
    defaultClass - the default class to use
    param - an additional parameter that will be passed to the bean factory; some factories may support parameters and behave different depending on the value passed in here
    
    Returns:
    the new bean
    
    Throws:
    
    ConfigurationRuntimeException - if an error occurs
  - createBean
```
public static Object createBean(BeanDeclaration data,
                Class<?> defaultClass)
                         throws ConfigurationRuntimeException
```
    Returns a bean instance for the specified declaration. This method is a short cut for createBean(data, null, null);.
    
    Parameters:
    data - the bean declaration
    defaultClass - the class to be used when in the declaration no class is specified
    
    Returns:
    the new bean
    
    Throws:
    
    ConfigurationRuntimeException - if an error occurs
  - createBean
```
public static Object createBean(BeanDeclaration data)
                         throws ConfigurationRuntimeException
```
    Returns a bean instance for the specified declaration. This method is a short cut for createBean(data, null);.
    
    Parameters:
    data - the bean declaration
    
    Returns:
    the new bean
    
    Throws:
    
    ConfigurationRuntimeException - if an error occurs

Class BeanHelper

Method Summary

Methods inherited from class java.lang.Object

Method Detail

registerBeanFactory

deregisterBeanFactory

registeredFactoryNames

getDefaultBeanFactory

setDefaultBeanFactory

initBean

initBeanProperties

setProperty

createBean

createBean

createBean