org.drombler.commons.context

Interface Context

All Known Implementing Classes:

AbstractContext, ContextWrapper, LocalProxyContext, ProxyContext, SimpleContext

public interface Context

A Context to find context-sensitive data.

Author:

puce

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.

Method Detail

find

<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.

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

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

Finds all instances of the specified type in this 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

<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.

Type Parameters:

T - the specified type

Parameters:

type - the type to listen for

listener - the ContextListener

removeContextListener

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

Unregisters a ContextListener for a specified type.

Type Parameters:

T - the specified type

Parameters:

type - the type to listen for

listener - the ContextListener