com.interface21.context.support
Class AbstractApplicationContext

java.lang.Object
  |
  +--com.interface21.context.support.AbstractApplicationContext

All Implemented Interfaces:

ApplicationContext, BeanFactory, ListableBeanFactory, MessageSource

Direct Known Subclasses:

AbstractXmlApplicationContext, StaticApplicationContext

public abstract class AbstractApplicationContext

extends java.lang.Object

implements ApplicationContext

Partial implementation of ApplicationContext. Doesn't mandate the type of storage used for configuration, but implements common functionality.

This class uses the Template Method design pattern, requiring concrete subclasses to implement protected abstract methods.

The context options may be supplied as a bean in the default bean factory, with the name "contextOptions".

A message source may be supplied as a bean in the default bean factory, with the name "messageSource". Else, message resolution is delegated to the parent context.

Since:

January 21, 2001

Version:

$Revision: 1.22 $

Author:

Rod Johnson

See Also:

refreshBeanFactory(), getBeanFactory(), OPTIONS_BEAN_NAME, MESSAGE_SOURCE_BEAN_NAME

Field Summary

protected org.apache.commons.logging.Log	logger Log4j logger used by this class.
static java.lang.String	MESSAGE_SOURCE_BEAN_NAME Name of the MessageSource bean in the factory.
static java.lang.String	OPTIONS_BEAN_NAME Name of options bean in the factory.

Constructor Summary

AbstractApplicationContext()
Create a new AbstractApplicationContext with no parent.

AbstractApplicationContext(ApplicationContext parent)
Create a new AbstractApplicationContext with the given parent context.

Method Summary

protected void	addListener(ApplicationListener l) Add a listener.
protected void	configureManagedObject(java.lang.Object o) If the object is context-aware, give it a reference to this object.
java.lang.String[]	getAliases(java.lang.String name) Return the aliases for the given bean name, if defined.
java.lang.Object	getBean(java.lang.String name) Try to find the bean instance in the hierarchy.
java.lang.Object	getBean(java.lang.String name, java.lang.Class requiredType) Return an instance (possibly shared or independent) of the given bean name.
int	getBeanDefinitionCount() Return the number of beans defined in the factory
java.lang.String[]	getBeanDefinitionNames() Return the names of all beans defined in this factory
java.lang.String[]	getBeanDefinitionNames(java.lang.Class type) Return the names of beans matching the given object type (including subclasses).
protected abstract ListableBeanFactory	getBeanFactory() Unimplemented interface method.
java.lang.String	getDisplayName() Return a friendly name for context
java.lang.String	getMessage(MessageSourceResolvable resolvable, java.util.Locale locale) Using all the attributes contained within the MessageSourceResolvable arg that was passed in (except for the locale attribute), try to resolve the message from the MessageSource contained within the Context. NOTE: We must throw a NoSuchMessageException on this method since at the time of calling this method we aren't able to determine if the defaultMessage attribute is null or not.
java.lang.String	getMessage(java.lang.String code, java.lang.Object[] args, java.util.Locale locale) Try to resolve the message.
java.lang.String	getMessage(java.lang.String code, java.lang.Object[] args, java.lang.String defaultMessage, java.util.Locale locale) Try to resolve the message.Return default message if no message was found.
ContextOptions	getOptions() Return context options.
ApplicationContext	getParent() Return the parent context, or null if there is no parent, and this is the root of the context hierarchy.
java.io.InputStream	getResourceAsStream(java.lang.String location) This implementation supports fully qualified URLs and appropriate (file) paths, via getResourceByPath.
java.lang.String	getResourceBasePath() This implementation returns the working directory of the Java VM.
protected java.io.InputStream	getResourceByPath(java.lang.String path) Return input stream to the resource at the given (file) path.
long	getStartupDate() Return the timestamp when this context was first loaded
boolean	isSingleton(java.lang.String name) Is this bean a singleton?
protected void	onRefresh() Callback method which can be overridden to add context-specific refresh work.
void	publishEvent(ApplicationEvent event) Publish the given event to all listeners.
void	refresh() Load or reload configuration.
protected abstract void	refreshBeanFactory() Subclasses must implement this method to perform the actual configuration load.
java.lang.Object	removeSharedObject(java.lang.String key) Remove a shared object added with a call to shareObject().
protected void	setDisplayName(java.lang.String displayName) To avoid endless constructor chaining, only concrete classes take this in their constructor, and then invoke this method
protected void	setParent(ApplicationContext ac) Subclasses may call this to set parent after constructor.
java.lang.Object	sharedObject(java.lang.String key) Retrieve a shared object added with a call to shareObject().
void	shareObject(java.lang.String key, java.lang.Object o) Put an object available for sharing.
java.lang.String	toString() Show information about this context

Methods inherited from class java.lang.Object

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

Field Detail

OPTIONS_BEAN_NAME

public static final java.lang.String OPTIONS_BEAN_NAME

Name of options bean in the factory. If none is supplied, a default ContextOptions instance will be used.

See Also:

ContextOptions

MESSAGE_SOURCE_BEAN_NAME

public static final java.lang.String MESSAGE_SOURCE_BEAN_NAME

Name of the MessageSource bean in the factory. If none is supplied, message resolution is delegated to the parent.

See Also:

MessageSource

logger

protected final org.apache.commons.logging.Log logger

Log4j logger used by this class. Available to subclasses.

Constructor Detail

AbstractApplicationContext

public AbstractApplicationContext()

Create a new AbstractApplicationContext with no parent.

AbstractApplicationContext

public AbstractApplicationContext(ApplicationContext parent)

Create a new AbstractApplicationContext with the given parent context.

Parameters:

parent - parent context

Method Detail

getParent

public ApplicationContext getParent()

Return the parent context, or null if there is no parent, and this is the root of the context hierarchy.

Specified by:

getParent in interface ApplicationContext

Returns:

the parent context, or null if there is no parent

setParent

protected void setParent(ApplicationContext ac)

Subclasses may call this to set parent after constructor. Note that parent shouldn't be changed: it should only be set later if it isn't available when an object of this class is created.

Parameters:

ac - parent context

getDisplayName

public java.lang.String getDisplayName()

Return a friendly name for context

Specified by:

getDisplayName in interface ApplicationContext

Returns:

a display name for the context

setDisplayName

protected void setDisplayName(java.lang.String displayName)

To avoid endless constructor chaining, only concrete classes take this in their constructor, and then invoke this method

getStartupDate

public final long getStartupDate()

Return the timestamp when this context was first loaded

Specified by:

getStartupDate in interface ApplicationContext

Returns:

the timestamp (ms) when this context was first loaded

getOptions

public final ContextOptions getOptions()

Return context options. These control reloading etc.

Specified by:

getOptions in interface ApplicationContext

Returns:

context options

refresh

public final void refresh()
                   throws ApplicationContextException

Load or reload configuration.

Specified by:

refresh in interface ApplicationContext

Throws:

ApplicationContextException - if the configuration was invalid or couldn't be found, or if configuration has already been loaded and reloading is forbidden DYNAMIC CLASSLOADER ISSUE...subclass to get classloader!?

onRefresh

protected void onRefresh()
                  throws ApplicationContextException

Callback method which can be overridden to add context-specific refresh work.

Throws:

ApplicationContextException - in case of errors during refresh

configureManagedObject

protected void configureManagedObject(java.lang.Object o)
                               throws ApplicationContextException

If the object is context-aware, give it a reference to this object. Note that the implementation of the ApplicationContextAware interface must check itself that if it is already initialized resp. if it wants to perform reinitialization.

Parameters:

o - object to invoke the setApplicationContext() method on, if it implements the ApplicationContextAware interface

publishEvent

public final void publishEvent(ApplicationEvent event)

Publish the given event to all listeners.

Specified by:

publishEvent in interface ApplicationContext

Parameters:

event - event to publish. The event may be application-specific, or a standard framework event.

addListener

protected void addListener(ApplicationListener l)

Add a listener. Any beans that are listeners are automatically added.

getResourceAsStream

public final java.io.InputStream getResourceAsStream(java.lang.String location)
                                              throws java.io.IOException

This implementation supports fully qualified URLs and appropriate (file) paths, via getResourceByPath. Throws a FileNotFoundException if getResourceByPath returns null.

Specified by:

getResourceAsStream in interface ApplicationContext

See Also:

getResourceByPath(java.lang.String)

getResourceByPath

protected java.io.InputStream getResourceByPath(java.lang.String path)
                                         throws java.io.IOException

Return input stream to the resource at the given (file) path.

Default implementation supports file paths, either absolute or relative to the application's working directory. This should be appropriate for standalone implementations but can be overridden, e.g. for implementations targetted at a container.

Parameters:

path - path to the resource

Returns:

InputStream for the specified resource, can be null if not found (instead of throwing an exception)

Throws:

java.io.IOException - exception when opening the specified resource

getResourceBasePath

public java.lang.String getResourceBasePath()

This implementation returns the working directory of the Java VM. This should be appropriate for standalone implementations but can be overridden for implementations targetted at a container.

Specified by:

getResourceBasePath in interface ApplicationContext

Following copied from interface: com.interface21.context.ApplicationContext

Returns:

the resource base path (ending with a separator), or null

sharedObject

public java.lang.Object sharedObject(java.lang.String key)

Description copied from interface: ApplicationContext

Retrieve a shared object added with a call to shareObject().

Specified by:

sharedObject in interface ApplicationContext

Following copied from interface: com.interface21.context.ApplicationContext

Returns:

the object, or null if no object is known under this name (this is not an error).

shareObject

public void shareObject(java.lang.String key,
                        java.lang.Object o)

Description copied from interface: ApplicationContext

Put an object available for sharing. Note that this method is not synchronized. As with Java 2 collections, it's up to calling code to ensure thread safety. Also, this doesn't work in a cluster. It's analogous to putting something in a ServletContext.

Specified by:

shareObject in interface ApplicationContext

Following copied from interface: com.interface21.context.ApplicationContext

Parameters:

key - object key

o - object to put

removeSharedObject

public java.lang.Object removeSharedObject(java.lang.String key)

Description copied from interface: ApplicationContext

Remove a shared object added with a call to shareObject(). Does nothing if the object was null.

Specified by:

removeSharedObject in interface ApplicationContext

Following copied from interface: com.interface21.context.ApplicationContext

Parameters:

key - the object was added with

Returns:

the object if it was found, or null.

getMessage

public java.lang.String getMessage(java.lang.String code,
                                   java.lang.Object[] args,
                                   java.lang.String defaultMessage,
                                   java.util.Locale locale)

Try to resolve the message.Return default message if no message was found.

Specified by:

getMessage in interface MessageSource

Parameters:

code - code to lookup up, such as 'calculator.noRateSet'

locale - Locale in which to do lookup

args - Array of arguments that will be filled in for params within the message (params look like "{0}", "{1,date}", "{2,time}" within a message).

defaultMessage - String to return if the lookup fails

Returns:

a resolved message if the lookup is successful; otherwise return the default message passed as a parameter

See Also:

java.text.MessageFormat

getMessage

public java.lang.String getMessage(java.lang.String code,
                                   java.lang.Object[] args,
                                   java.util.Locale locale)
                            throws NoSuchMessageException

Try to resolve the message. Treat as an error if the message can't be found.

Specified by:

getMessage in interface MessageSource

Parameters:

code - code to lookup up, such as 'calculator.noRateSet'

locale - Locale in which to do lookup

args - Array of arguments that will be filled in for params within the message (params look like "{0}", "{1,date}", "{2,time}" within a message).

Returns:

message

Throws:

NoSuchMessageException - not found in any locale

See Also:

java.text.MessageFormat

getMessage

public java.lang.String getMessage(MessageSourceResolvable resolvable,
                                   java.util.Locale locale)
                            throws NoSuchMessageException

Using all the attributes contained within the MessageSourceResolvable arg that was passed in (except for the locale attribute), try to resolve the message from the MessageSource contained within the Context.

NOTE: We must throw a NoSuchMessageException on this method since at the time of calling this method we aren't able to determine if the defaultMessage attribute is null or not.

Specified by:

getMessage in interface MessageSource

Parameters:

resolvable - Value object storing 4 attributes required to properly resolve a message.

locale - Locale to be used as the "driver" to figuring out what message to return.

Returns:

message Resolved message.

Throws:

NoSuchMessageException - not found in any locale

See Also:

java.text.MessageFormat

getBean

public java.lang.Object getBean(java.lang.String name)
                         throws BeansException

Try to find the bean instance in the hierarchy.

Specified by:

getBean in interface BeanFactory

Following copied from interface: com.interface21.beans.factory.BeanFactory

Parameters:

name - name of the bean to return

Returns:

the instance of the bean

Throws:

NoSuchBeanDefinitionException - if there's no such bean definition

getBean

public java.lang.Object getBean(java.lang.String name,
                                java.lang.Class requiredType)
                         throws BeansException

Description copied from interface: BeanFactory

Return an instance (possibly shared or independent) of the given bean name. Provides a measure of type safety by throwing an exception if the bean is not of the required type. This method allows a bean factory to be used as a replacement for the Singleton or Prototype design pattern.
Note that callers should retain references to returned objects. There is no guarantee that this method will be implemented to be efficient. For example, it may be synchronized, or may need to run an RDBMS query.

Specified by:

getBean in interface BeanFactory

Following copied from interface: com.interface21.beans.factory.BeanFactory

Parameters:

name - name of the bean to return

requiredType - type the bean may match. Can be an interface or superclass of the actual class. For example, if the value is Object.class, this method will succeed whatever the class of the returned instance.

Returns:

the instance of the bean

Throws:

BeanNotOfRequiredTypeException - if the bean is not of the required type

NoSuchBeanDefinitionException - if there's no such bean definition

isSingleton

public boolean isSingleton(java.lang.String name)
                    throws NoSuchBeanDefinitionException

Description copied from interface: BeanFactory

Is this bean a singleton? That is, will getBean() always return the same object?

Specified by:

isSingleton in interface BeanFactory

Following copied from interface: com.interface21.beans.factory.BeanFactory

Parameters:

name - name of the bean to query

Returns:

is this bean a singleton

Throws:

NoSuchBeanDefinitionException - if there is no bean with the given name

getAliases

public java.lang.String[] getAliases(java.lang.String name)

Description copied from interface: BeanFactory

Return the aliases for the given bean name, if defined.

Specified by:

getAliases in interface BeanFactory

Following copied from interface: com.interface21.beans.factory.BeanFactory

Parameters:

name - the bean name to check for aliases

Returns:

the aliases, or an empty array if none

getBeanDefinitionCount

public int getBeanDefinitionCount()

Description copied from interface: ListableBeanFactory

Return the number of beans defined in the factory

Specified by:

getBeanDefinitionCount in interface ListableBeanFactory

Following copied from interface: com.interface21.beans.factory.ListableBeanFactory

Returns:

the number of beans defined in the factory

getBeanDefinitionNames

public java.lang.String[] getBeanDefinitionNames()

Description copied from interface: ListableBeanFactory

Return the names of all beans defined in this factory

Specified by:

getBeanDefinitionNames in interface ListableBeanFactory

Following copied from interface: com.interface21.beans.factory.ListableBeanFactory

Returns:

the names of all beans defined in this factory. Returns the empty String[], rather than null, if no beans are defined.

getBeanDefinitionNames

public java.lang.String[] getBeanDefinitionNames(java.lang.Class type)

Description copied from interface: ListableBeanFactory

Return the names of beans matching the given object type (including subclasses).

Specified by:

getBeanDefinitionNames in interface ListableBeanFactory

Following copied from interface: com.interface21.beans.factory.ListableBeanFactory

Parameters:

type - class or interface to match

Returns:

the names of beans matching the given object type (including subclasses). Never returns null.

toString

public java.lang.String toString()

Show information about this context

Overrides:

toString in class java.lang.Object

refreshBeanFactory

protected abstract void refreshBeanFactory()
                                    throws ApplicationContextException

Subclasses must implement this method to perform the actual configuration load.

getBeanFactory

protected abstract ListableBeanFactory getBeanFactory()

Unimplemented interface method. Subclasses must implement this efficiently, so that it can be called repeatedly without a performance penalty.

Returns:

this application context's default BeanFactory