MessageQueue

Revision as of 17:31, 26 March 2013

MessageQueue API for JavaScript.

In JavaScript a MessageQueue can be created by calling Message.installHook() method. A description of MessageQueue behaviour can be found [Messages#How_messages_are_processed here].

installHook parameters:

• processCallback - function, optional. The method that should process the messages skipping the engine handlers list.
• msgName - string, mandatory. The message name for the queue filtering.
• workers - integer, mandatory. The number of workers that should be used for message processing.
• trapCallback - function, optional. The method that should be called when a queue overload is detected.
• trapCount - integer, mandatory if trapCallback is present. The number of messages in the queue when we should be alerted.
• filter - string, optional, can be repeated. Optional message filter. Should be in form 'name=value'.

Examples:

installHook("engine.timer",1);

Creates a MessageQueue for engine.timer message with one processing thread.

installHook(callback,"call.route",2,"called=123");

Creates a MessageQueue for call.route message, who has called=123. Two processing threads will be created. When a message needs to be processed the callback method will be called.

installHook(callback,"call.route",2,trapCallback,50,"called=123");

The same behaviour as above only that the trapCallback method will be called when in the queue exists more than 50 unprocessed messages.