com.interface21.context
Interface ApplicationContext

All Superinterfaces:

BeanFactory, ListableBeanFactory, MessageSource

All Known Subinterfaces:

WebApplicationContext

All Known Implementing Classes:

AbstractApplicationContext

public interface ApplicationContext

extends MessageSource, ListableBeanFactory

Interface to provide configuration for an application. This is read-only while the application is running, but may be reloaded if the implementation supports this.

The configuration provides:

• The ability to resolve messages, supporting internationalization.
• The ability to publish events. Implementations must provide a means of registering event listeners.
• The ability to share objects by publishing them to the context.
• Bean factory methods, inherited from ListableBeanFactory. This avoids the need for applications to use singletons.
• Notification of beans initialized by the context of the context, enabling communication with the rest of the application, for example by publishing events. The BeanFactory superinterface provides no similar mechanism.
• Inheritance from a parent context. Definitions in a descendant context will always take priority. This means, for example, that a single parent context can be used by an entire web application, while each servlet has its own child context that is independent of that of any other servlet.

Version:

$Revision: 1.8 $

Author:

Rod Johnson

Method Summary

java.lang.String	getDisplayName() Return a friendly name for this context.
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) Open an InputStream to the specified resource: Must support fully qualified URLs, e.g.
java.lang.String	getResourceBasePath() Return the base path for relatively addressed resources for this application context.
long	getStartupDate() Return the timestamp when this context was first loaded
void	publishEvent(ApplicationEvent event) Notify all listeners registered with this application of an application event.
void	refresh() Load or refresh the persistent representation of the configuration, which might for example be an XML file, properties file or relational database schema.
java.lang.Object	removeSharedObject(java.lang.String key) Remove a shared object added with a call to shareObject().
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.

Methods inherited from interface com.interface21.context.MessageSource

getMessage, getMessage, getMessage

Methods inherited from interface com.interface21.beans.factory.ListableBeanFactory

getBeanDefinitionCount, getBeanDefinitionNames, getBeanDefinitionNames

Methods inherited from interface com.interface21.beans.factory.BeanFactory

getAliases, getBean, getBean, isSingleton

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.

Returns:

the parent context, or null if there is no parent

getDisplayName

public java.lang.String getDisplayName()

Return a friendly name for this context.

Returns:

a display name for this context

getStartupDate

public long getStartupDate()

Return the timestamp when this context was first loaded

Returns:

the timestamp (ms) when this context was first loaded

getOptions

public ContextOptions getOptions()

Return context options. These control reloading etc.

ApplicationContext implementations may subclass ContextOptions to add additional properties. It must always be a bean.

Returns:

context options (must not be null).

refresh

public void refresh()
             throws ApplicationContextException

Load or refresh the persistent representation of the configuration, which might for example be an XML file, properties file or relational database schema.

Throws:

ApplicationContextException - if the config cannot be loaded

publishEvent

public void publishEvent(ApplicationEvent event)

Notify all listeners registered with this application of an application event. Events may be framework events (such as RequestHandledEvent) or application-specific events.

Parameters:

event - event to publish

getResourceAsStream

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

Open an InputStream to the specified resource:

• Must support fully qualified URLs, e.g. "file:C:/test.dat".
• Should support relative file paths, e.g. "WEB-INF/test.dat".
• May allow for absolute file paths, e.g. "C:/test.dat".

Note that the safest way to access an absolute file path is via a "file:" URL, as this must be supported by all implementations.

Note: Callers are responsible for closing the input stream.

Parameters:

location - location to the resource

Returns:

InputStream for the specified resource

Throws:

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

getResourceBasePath

public java.lang.String getResourceBasePath()

Return the base path for relatively addressed resources for this application context. Normally, this path will be the same as the one that getResourceAsStream uses for evaluating relative paths.

Note that this method returns null if this application context does not have a dedicated base path. Accordingly, getResourceAsStream may not support relative paths at all, or use more than one base path for evaluating relative paths.

Returns:

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

shareObject

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

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.

Parameters:

key - object key

o - object to put

sharedObject

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

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

Returns:

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

removeSharedObject

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

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

Parameters:

key - the object was added with

Returns:

the object if it was found, or null.