org.drombler.commons.context

Class ContextWrapper

java.lang.Object

org.drombler.commons.context.ContextWrapper

All Implemented Interfaces:

Context

public class ContextWrapper
extends Object
implements Context

A Context wrapper wraps another Context.

Author:

puce

Constructor Summary

Constructors

Constructor and Description
ContextWrapper(Context context) Creates a new instance of this class.

Method Summary

Modifier and Type	Method and Description
<T> void	addContextListener(Class<T> type, ContextListener<T> listener) Registers a ContextListener for a specified type.
<T> T	find(Class<T> type) Finds an instance of the specified type in this context.
<T> Collection<? extends T>	findAll(Class<T> type) Finds all instances of the specified type in this context.
<T> void	removeContextListener(Class<T> type, ContextListener<T> listener) Unregisters a ContextListener for a specified type.

Methods inherited from class java.lang.Object

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

Constructor Detail

ContextWrapper

public ContextWrapper(Context context)

Creates a new instance of this class.

Parameters:

context - the context to wrap

Method Detail

find

public <T> T find(Class<T> type)

Finds an instance of the specified type in this context. If this context has more than one instance of the specified type, the first one found will be returned.

Specified by:

find in interface Context

Type Parameters:

T - the specified type

Parameters:

type - the specified type

Returns:

the first instance found in this context with the specified type, or null if no instance was found. TODO: return Optional?

findAll

public <T> Collection<? extends T> findAll(Class<T> type)

Finds all instances of the specified type in this context.

Specified by:

findAll in interface Context

Type Parameters:

T - the specified type

Parameters:

type - the specified type

Returns:

a collection with all instances found in this context with the specified type, or an empty collection if no instance was found TODO: return List instead of Collection?
TODO: return <T> instead of <? extends T>?

addContextListener

public <T> void addContextListener(Class<T> type,
                                   ContextListener<T> listener)

Registers a ContextListener for a specified type. The listener will be notified when instances of the specified type get added or removed.

Specified by:

addContextListener in interface Context

Type Parameters:

T - the specified type

Parameters:

type - the type to listen for

listener - the ContextListener

removeContextListener

public <T> void removeContextListener(Class<T> type,
                                      ContextListener<T> listener)

Unregisters a ContextListener for a specified type.

Specified by:

removeContextListener in interface Context

Type Parameters:

T - the specified type

Parameters:

type - the type to listen for

listener - the ContextListener