public interface SubscribableChannel extends MessageChannel
MessageChannel that maintains a registry of subscribers and invokes
 them to handle messages sent through this channel.INDEFINITE_TIMEOUT| Modifier and Type | Method and Description | 
|---|---|
boolean | 
subscribe(MessageHandler handler)
Register a message handler. 
 | 
boolean | 
unsubscribe(MessageHandler handler)
Un-register a message handler. 
 | 
send, sendboolean subscribe(MessageHandler handler)
true if the handler was subscribed or false if it
 was already subscribed.boolean unsubscribe(MessageHandler handler)
true if the handler was un-registered, or false
 if was not registered.