Package com.intellij.util.messages.impl

Class MessageBusImpl

java.lang.Object

com.intellij.util.messages.impl.MessageBusImpl

All Implemented Interfaces:

Disposable, MessageBus

public class MessageBusImpl
extends java.lang.Object
implements MessageBus

Nested Class Summary

Nested classes/interfaces inherited from interface com.intellij.openapi.Disposable

Disposable.Parent

Constructor Summary

Constructors

Constructor and Description
MessageBusImpl(MessageBusOwner owner, MessageBusImpl parentBus)

Method Summary

Modifier and Type	Method and Description
com.intellij.util.messages.impl.MessageBusConnectionImpl	connect() Allows to create new connection that is not bound to any Disposable.
com.intellij.util.messages.impl.MessageBusConnectionImpl	connect(Disposable parentDisposable) Allows to create new connection that is bound to the given Disposable.
void	dispose() Disposes current bus, i.e.
void	disposeConnection()
void	disposeConnectionChildren()
MessageBus	getParent() Message buses can be organised into hierarchies.
boolean	hasUndeliveredEvents(Topic<?> topic)
boolean	isDisposed() Returns true if this bus is disposed.
void	setIgnoreParentLazyListeners(boolean ignoreParentLazyListeners)
void	setLazyListeners(java.util.concurrent.ConcurrentMap<java.lang.String,java.util.List<ListenerDescriptor>> map) Must be a concurrent map, because remove operation may be concurrently performed (synchronized only per topic).
void	setMessageDeliveryListener(MessageDeliveryListener listener)
<L> L	syncPublisher(Topic<L> topic) Allows to retrieve an interface for publishing messages to the target topic.
java.lang.String	toString()
void	unsubscribePluginListeners(PluginDescriptor pluginDescriptor)

Methods inherited from class java.lang.Object

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

Constructor Detail

MessageBusImpl

public MessageBusImpl(MessageBusOwner owner,
                      MessageBusImpl parentBus)

Method Detail

setIgnoreParentLazyListeners

public void setIgnoreParentLazyListeners(boolean ignoreParentLazyListeners)

setLazyListeners

public void setLazyListeners(java.util.concurrent.ConcurrentMap<java.lang.String,java.util.List<ListenerDescriptor>> map)

Must be a concurrent map, because remove operation may be concurrently performed (synchronized only per topic).

getParent

public MessageBus getParent()

Description copied from interface: MessageBus

Message buses can be organised into hierarchies. That allows facilities broadcasting.

Current method exposes parent bus (if any is defined).

Specified by:

getParent in interface MessageBus

Returns:

parent bus (if defined)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

connect

public com.intellij.util.messages.impl.MessageBusConnectionImpl connect()

Description copied from interface: MessageBus

Allows to create new connection that is not bound to any Disposable.

Specified by:

connect in interface MessageBus

Returns:

newly created connection

connect

public com.intellij.util.messages.impl.MessageBusConnectionImpl connect(Disposable parentDisposable)

Description copied from interface: MessageBus

Allows to create new connection that is bound to the given Disposable. That means that returned connection will be automatically released if given disposable parent is collected.

Specified by:

connect in interface MessageBus

Parameters:

parentDisposable - target parent disposable to which life cycle newly created connection shall be bound

Returns:

newly created connection which life cycle is bound to the given disposable parent

syncPublisher

public <L> L syncPublisher(Topic<L> topic)

Description copied from interface: MessageBus

Allows to retrieve an interface for publishing messages to the target topic.

Basically, the whole processing looks as follows:

1. Messaging clients create new connections within the target message bus and subscribe to the target topics;
2. Every time somebody wants to send a message for particular topic, he or she calls current method and receives object that conforms to the business interface of the target topic. Every method call on that object is dispatched by the messaging infrastructure to the subscribers. broadcasting is performed if necessary as well;

It's also very important to understand message processing strategy in case of nested dispatches. Consider the following situation:

1. Subscriber1 and subscriber2 are registered for the same topic within the same message bus;
2. Message1 is sent to that topic within the same message bus;
3. Queued messages delivery starts;
4. Queued messages delivery ends as there are no messages queued but not dispatched;
5. Message1 is queued for delivery to both subscribers;
6. Queued messages delivery starts;
7. Message1 is being delivered to the subscriber1;
8. Subscriber1 sends message2 to the same topic within the same bus;
9. Queued messages delivery starts;
10. Important: subscriber2 is being notified about all queued but not delivered messages, i.e. its callback is invoked for the message₁;
11. Queued messages delivery ends because all subscribers have been notified on the message1;
12. Message2 is queued for delivery to both subscribers;
13. Queued messages delivery starts;
14. Subscriber1 is notified on message2
15. Subscriber2 is notified on message2

Thread-safety. All subscribers are notified sequentially from the calling thread.

Memory management. Returned objects are very light-weight and stateless, so, they are cached by the message bus in 'per-topic' manner. That means that caller of this method is not obliged to keep returned reference along with the reference to the message for further publishing. It's enough to keep reference to the message bus only and publish like 'messageBus.syncPublisher(targetTopic).targetMethod()'.

Specified by:

syncPublisher in interface MessageBus

Type Parameters:

L - business interface of the target topic

Parameters:

topic - target topic

Returns:

publisher for target topic

unsubscribePluginListeners

public void unsubscribePluginListeners(PluginDescriptor pluginDescriptor)

disposeConnectionChildren

public final void disposeConnectionChildren()

disposeConnection

public final void disposeConnection()

dispose

public final void dispose()

Description copied from interface: MessageBus

Disposes current bus, i.e. drops all queued but not delivered messages (if any) and disallows further connections.

Specified by:

dispose in interface Disposable

Specified by:

dispose in interface MessageBus

isDisposed

public boolean isDisposed()

Description copied from interface: MessageBus

Returns true if this bus is disposed.

Specified by:

isDisposed in interface MessageBus

hasUndeliveredEvents

public boolean hasUndeliveredEvents(Topic<?> topic)

Specified by:

hasUndeliveredEvents in interface MessageBus

Returns:

true when events in the given topic are being dispatched in the current thread, and not all listeners have received the events yet.

setMessageDeliveryListener

public void setMessageDeliveryListener(MessageDeliveryListener listener)