org.gradle.listener

Interface ListenerManager

All Known Implementing Classes:

DefaultListenerManager

public interface ListenerManager

Unified manager for all listeners for Gradle. Provides a simple way to find all listeners of a given type in the system. While the methods work with any Object, in general only interfaces should be used as listener types. Also, due to implementation details, any listener method with a non-void return type will return a null.

Method Summary

Methods

Modifier and Type	Method and Description
void	addListener(Class<?> listenerType, String method, Closure listenerClosure) Added a listener implemented via a Groovy closure.
void	addListener(Object listener) Added a listener.
<T> ListenerBroadcast<T>	createAnonymousBroadcaster(Class<T> listenerClass) Returns a broadcaster for the given listenerClass.
ListenerManager	createChild() Creates a child ListenerManager.
<T> T	getBroadcaster(Class<T> listenerClass) Returns a broadcaster for the given listenerClass.
void	removeListener(Object listener) Removes a listener.
void	useLogger(Object logger) Uses the given object as a logger.

Method Detail

addListener

void addListener(Object listener)

Added a listener. A single object can implement multiple interfaces, and all interfaces are registered by a single invocation of this method. There is no order dependency: if a broadcaster has already been made for type T, the listener will be registered with it if (listener instanceof T) returns true.

Parameters:

listener - the listener to add.

addListener

void addListener(Class<?> listenerType,
               String method,
               Closure listenerClosure)

Added a listener implemented via a Groovy closure. The closure can implement a single method of the given listenerType class. There is no order dependency: if a broadcaster has already been made for listenerType, the closure will be registered with it.

Parameters:

listenerType - The class of the listener type for which the closure is a method implementation.

method - The name of the method in the listenerType class for which the closure is an implementation.

listenerClosure - The closure containing the implementation of the listener method.

removeListener

void removeListener(Object listener)

Removes a listener. A single object can implement multiple interfaces, and all interfaces are unregistered by a single invocation of this method. There is no order dependency: if a broadcaster has already been made for type T, the listener will be unregistered with it if (listener instanceof T) returns true.

Parameters:

listener - the listener to remove.

getBroadcaster

<T> T getBroadcaster(Class<T> listenerClass)

Returns a broadcaster for the given listenerClass. If there are no registered listeners for that type, a broadcaster is returned which does not forward method calls to any listeners. The returned broadcasters are live, that is their list of listeners can be updated by calls to addListener(Object) and removeListener(Object) after they have been returned. Broadcasters are also cached, so that repeatedly calling this method with the same listenerClass returns the same broadcaster object.

Parameters:

listenerClass - The type of listener for which to return a broadcaster.

Returns:

The broadcaster that forwards method calls to all listeners of the same type that have been (or will be) registered with this manager.

createAnonymousBroadcaster

<T> ListenerBroadcast<T> createAnonymousBroadcaster(Class<T> listenerClass)

Returns a broadcaster for the given listenerClass. The returned broadcaster will delegate to the canonical broadcaster returned by getBroadcaster(Class) for the given listener type. However, it can also have listeners assigned/removed directly to/from it. This allows these "anonymous" broadcasters to specialize what listeners receive messages. Each call creates a new broadcaster, so that client code can create as many "facets" of the listener as they need. The client code must provide some way for its users to register listeners on the specialized broadcasters.

Parameters:

listenerClass - The type of listener for which to create a broadcaster.

Returns:

A broadcaster that forwards method calls to all listeners assigned to it, or of the same type that have been (or will be) registered with this manager.

useLogger

void useLogger(Object logger)

Uses the given object as a logger. Each listener class has exactly one logger associated with it. Any existing logger for the listener class is discarded.

Parameters:

logger - The new logger to use.

createChild

ListenerManager createChild()

Creates a child ListenerManager. All events broadcast in the child will be received by the listeners registered in the parent. However, the reverse is not true: events broadcast in the parent are not received by the listeners in the children. The child inherits the loggers of its parent, though these can be replaced.

Returns:

The child