LifeCycleBeanProvider (JGUIraffe BOM 1.3.1 API)

java.lang.Object
- net.sf.jguiraffe.di.impl.providers.LifeCycleBeanProvider

All Implemented Interfaces:

BeanInitializer, BeanProvider

Direct Known Subclasses:

FactoryBeanProvider, SingletonBeanProvider
```
public abstract class LifeCycleBeanProvider
extends Object
implements BeanProvider, BeanInitializer
```
An abstract base class for BeanProvider implementations with life-cycle support.

A LifeCycleBeanProvider has the following properties:
- A (usually simple) BeanProvider for actually creating an instance of the managed bean.
- An optional Invokable object for initializing the newly created bean instance.
This base class provides basic functionality for the creation and initialization of beans. It also implements the methods related to life-cycle support of the BeanProvider interface in a meaningful way. There are two methods that are intended to be called by concrete sub classes: createBean() and fetchBean().

createBean(), as its name implies, creates a new instance of the managed bean class. This is done by invoking the BeanProvider for creating new beans. After that the Invokable object is called on the newly created bean. The creation of a bean through the bean provider may cause an endless loop if there are cyclic dependencies (e.g. bean A needs bean B as a constructor argument and vice verse). Such cycles are detected and lead to a InjectionException exception being thrown.

The fetchBean() method checks whether a bean instance has already been created. If this is the case, it is directly returned. Otherwise createBean() is called for creating a new instance. Depending on their semantics derived classes decide, which of these methods to call. This decision must be implemented in the getBean() method; all other methods defined by the BeanProvider interface are already implemented by this base class.

Implementation note: This class is intended to be used together with a correct implementation of the BeanContext interface. It is not thread-safe by itself, but if the bean context handles transactions properly, it can be used in an environment with multiple threads accessing the bean context concurrently.
Version:

$Id: LifeCycleBeanProvider.java 208 2012-02-11 20:57:33Z oheger $

Author:

Oliver Heger

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`LifeCycleBeanProvider(BeanProvider createProvider)` Creates a new instance of `LifeCycleBeanProvider` and initializes it with the `BeanProvider` for creating the bean instance.
`protected`	`LifeCycleBeanProvider(BeanProvider createProvider, Invokable initinv)` Creates a new instance of `LifeCycleBeanProvider` and initializes it with the `BeanProvider` for creating the bean instance and an `Invokable` for initializing it.

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`protected boolean`	`canInitialize(DependencyProvider dependencyProvider)` Checks whether initialization of the bean is now possible.
`protected Object`	`createBean(DependencyProvider dependencyProvider)` Creates and initializes a new bean instance.
`protected Object`	`doCreateBean(DependencyProvider dependencyProvider)` Creates a new bean instance.
`protected Object`	`fetchBean(DependencyProvider dependencyProvider)` Returns the bean instance created by this provider.
`protected Object`	`fetchInitializedBeanInstance(Object bean, DependencyProvider dependencyProvider)` Returns the initialized bean instance.
`Class<?>`	`getBeanClass(DependencyProvider dependencyProvider)` Returns the class of the bean managed by this provider.
`BeanProvider`	`getBeanCreator()` Returns the `BeanProvider` that is responsible for creating a new bean instance.
`Invokable`	`getBeanInitializer()` Returns the `Invokable` object responsible for initializing the newly created bean.
`Set<Dependency>`	`getDependencies()` Returns the dependencies of this bean provider.
`Long`	`getLockID()` Returns the ID of the locking transaction.
`protected boolean`	`hasBean()` Returns a flag whether a bean instance has already been created.
`protected void`	`initBean(Object bean, DependencyProvider dependencyProvider)` Deprecated. This method is not called any more during bean creation; instead `fetchInitializedBeanInstance(Object, DependencyProvider)` is invoked
`void`	`initialize(DependencyProvider dependencyProvider)` Performs initialization.
`boolean`	`isBeanAvailable()` Returns a flag whether the bean managed by this provider is available.
`protected void`	`resetBean()` Resets any so far created bean.
`void`	`setLockID(Long lid)` Sets the ID of the locking transaction.
`void`	`shutdown(DependencyProvider depProvider)` Notifies this `BeanProvider` that it is no longer needed.
`String`	`toString()` Returns a string representation of this object.

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

Methods inherited from interface net.sf.jguiraffe.di.BeanProvider
getBean

- Constructor Detail
  - LifeCycleBeanProvider
```
protected LifeCycleBeanProvider(BeanProvider createProvider,
                                Invokable initinv)
```
    Creates a new instance of LifeCycleBeanProvider and initializes it with the BeanProvider for creating the bean instance and an Invokable for initializing it.
    
    Parameters:
    
    createProvider - the bean provider for creating a bean instance (must not be null)
    
    initinv - an optional invocation object with initialization code for the newly created bean
    
    Throws:
    
    IllegalArgumentException - if the bean provider is null
  - LifeCycleBeanProvider
```
protected LifeCycleBeanProvider(BeanProvider createProvider)
```
    Creates a new instance of LifeCycleBeanProvider and initializes it with the BeanProvider for creating the bean instance.
    
    Parameters:
    
    createProvider - the bean provider for creating a bean instance (must not be null)
    
    Throws:
    
    IllegalArgumentException - if the bean provider is null
- Method Detail
  - getBeanCreator
```
public BeanProvider getBeanCreator()
```
    Returns the BeanProvider that is responsible for creating a new bean instance.
    
    Returns:
    
    the bean provider for creating new bean instances
  - getBeanInitializer
```
public Invokable getBeanInitializer()
```
    Returns the Invokable object responsible for initializing the newly created bean. This method never returns null. If no initializer was set, a default initializer object (that does not have any effect) is returned.
    
    Returns:
    
    the invocation object used for initialization
  - getBeanClass
```
public Class<?> getBeanClass(DependencyProvider dependencyProvider)
```
    Returns the class of the bean managed by this provider. This class is determined by the BeanProvider for creating new bean instances.
    
    Specified by:
    
    getBeanClass in interface BeanProvider
    
    Parameters:
    
    dependencyProvider - the dependency provider
    
    Returns:
    
    the class of the managed bean
    
    Throws:
    
    InjectionException - if an error occurs determining the class
  - getDependencies
```
public Set<Dependency> getDependencies()
```
    Returns the dependencies of this bean provider. This implementation obtains the dependencies of the creation bean provider and the invocation object for initialization and returns a union.
    
    Specified by:
    
    getDependencies in interface BeanProvider
    
    Returns:
    
    the dependencies of this bean provider
    
    See Also:
    
    Dependency
  - getLockID
```
public Long getLockID()
```
    Returns the ID of the locking transaction. If this method returns a non null value, this bean provider must not be used by a concurrent transaction.
    
    Specified by:
    
    getLockID in interface BeanProvider
    
    Returns:
    
    the ID of the locking transaction
  - setLockID
```
public void setLockID(Long lid)
```
    Sets the ID of the locking transaction. This indicates that this bean provider is blocked by the specified transaction.
    
    Specified by:
    
    setLockID in interface BeanProvider
    
    Parameters:
    
    lid - the ID of the locking transaction
    
    See Also:
    
    BeanProvider.getLockID()
  - isBeanAvailable
```
public boolean isBeanAvailable()
```
    Returns a flag whether the bean managed by this provider is available. This implementation checks whether the bean is currently created. If this is the case, it is not available.
    
    Specified by:
    
    isBeanAvailable in interface BeanProvider
    
    Returns:
    
    a flag whether the managed bean is available
  - shutdown
```
public void shutdown(DependencyProvider depProvider)
```
    Notifies this BeanProvider that it is no longer needed. This is just an empty dummy implementation. Derived classes that support shutdown handling have to override it.
    
    Specified by:
    
    shutdown in interface BeanProvider
    
    Parameters:
    
    depProvider - the DependencyProvider
  - initialize
```
public void initialize(DependencyProvider dependencyProvider)
```
    Performs initialization. This method is called by the dependency provider if initialization has to be delayed because of cyclic dependencies. It invokes the initializer.
    
    Specified by:
    
    initialize in interface BeanInitializer
    
    Parameters:
    
    dependencyProvider - the dependency provider
  - toString
```
public String toString()
```
    Returns a string representation of this object. This string also contains information about the bean provider used for creating the bean and the invocation object for the initialization.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    a string for this object
  - createBean
```
protected Object createBean(DependencyProvider dependencyProvider)
```
    Creates and initializes a new bean instance. This method is reentrant, which is necessary if there are cycles in the dependencies. In this case a bean that is only partly initialized may be returned. It is also possible that the cycles cannot be resolved, then an exception is thrown.
    
    Parameters:
    
    dependencyProvider - the dependency provider
    
    Returns:
    
    the newly created bean instance
    
    Throws:
    
    InjectionException - if an error occurs
  - fetchBean
```
protected Object fetchBean(DependencyProvider dependencyProvider)
```
    Returns the bean instance created by this provider. If no instance has been created yet, this is done now by invoking createBean(). Otherwise the bean instance is directly returned. If the dependencies contain cyclic references, it is possible that a bean instance is returned, which has not yet been fully initialized. Cycles that cannot be resolved cause an exception.
    
    Parameters:
    
    dependencyProvider - the dependency provider
    
    Returns:
    
    the bean instance managed by this provider
    
    Throws:
    
    InjectionException - if an error occurs
  - canInitialize
```
protected boolean canInitialize(DependencyProvider dependencyProvider)
```
    Checks whether initialization of the bean is now possible. This method tests whether all dependencies required for the bean's initialization are currently available.
    
    Parameters:
    
    dependencyProvider - the dependency provider
    
    Returns:
    
    a flag whether initialization can now be performed
  - hasBean
```
protected boolean hasBean()
```
    Returns a flag whether a bean instance has already been created. This can be used by derived classes for adapting their behavior. This implementation returns true if and only if a bean instance has been created and fully initialized.
    
    Returns:
    
    a flag whether a bean instance has been created
  - resetBean
```
protected void resetBean()
```
    Resets any so far created bean. This method can be called by derived classes to reset this bean provider. In a following call to fetchBean() a completely new bean will be created.
  - doCreateBean
```
protected Object doCreateBean(DependencyProvider dependencyProvider)
```
    Creates a new bean instance. This method is called by createBean() for actually creating the bean.
    
    Parameters:
    
    dependencyProvider - the dependency provider
    
    Returns:
    
    the new bean instance
    
    Throws:
    
    InjectionException - if an error occurs
  - initBean
```
@Deprecated
protected void initBean(Object bean,
                                     DependencyProvider dependencyProvider)
```
    Deprecated. This method is not called any more during bean creation; instead fetchInitializedBeanInstance(Object, DependencyProvider) is invoked
    
    Initializes a newly created bean instance. This method is called by createBean() for each new bean instance. This implementation invokes the initializer and notifies the DependencyProvider about the creation of a new bean.
    
    Parameters:
    
    bean - the bean to initialize
    
    dependencyProvider - the dependency provider
    
    Throws:
    
    InjectionException - if an error occurs
  - fetchInitializedBeanInstance
```
protected Object fetchInitializedBeanInstance(Object bean,
                                              DependencyProvider dependencyProvider)
```
    Returns the initialized bean instance. This method is called by createBean() for each new bean instance. Its purpose is to execute the initializer script on the bean. This implementation invokes the initializer and notifies the DependencyProvider about the creation of a new bean. Note that the bean returned by the initializer script is the result of this method. Thus it is possible that a different bean than passed to the method becomes the managed bean of this provider. However, if the initializer returns null, the passed in bean is returned.
    
    Parameters:
    
    bean - the bean to initialize
    
    dependencyProvider - the dependency provider
    
    Returns:
    
    the bean instance
    
    Throws:
    
    InjectionException - if an error occurs
    
    Since:
    
    1.1

Class LifeCycleBeanProvider

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface net.sf.jguiraffe.di.BeanProvider

Constructor Detail

LifeCycleBeanProvider

LifeCycleBeanProvider

Method Detail

getBeanCreator

getBeanInitializer

getBeanClass

getDependencies

getLockID

setLockID

isBeanAvailable

shutdown

initialize

toString

createBean

fetchBean

canInitialize

hasBean

resetBean

doCreateBean

initBean

fetchInitializedBeanInstance