1. Programmer's Guide
  2. OCCI Application Programming Interface
  3. Listener Class

13.17 Listener Class

The Listener class encapsulates the ability to listen for Messages, on behalf of registered Agents, at specified queues.

Table 13-23 Summary of Listener Methods

Method Summary

Listener()

Listener class constructor.

getAgentList()

Retrieves the list of Agents for which the Listener provides its services.

getTimeOutForListen()

Retrieves the time out for a call.

listen()

Listens for Messages and returns the name of the Agent for whom a Message is intended.

setAgentList()

Specifies the list of Agents for which the Listener provides its services.

setTimeOutForListen()

Specifies the time out for a listen() call.

13.17.1 Listener()

Listener class constructor.

Syntax Description 
Listener(
   const Connection* conn);

Creates a Listener object. 

Listener(
   const Connection* conn
   vector<Agent> &aglist,
   int waitTime=0);

Creates a Listener object and sets the list of Agents on behalf of which it listens on queues. Also sets the waiting time; default: no waiting.

Parameter Description 
conn

The connection of the new Listener object. 

aglist

The list of agents on behalf of which the Listener object waits on queues; clients of this Listener. 

waitTime

The time to wait on queues for messages of interest for the clients; in seconds.

13.17.2 getAgentList()

Retrieves the list of Agents for which the Listener provides its services.

Syntax

vector<Agent> getAgentList() const;

13.17.3 getTimeOutForListen()

Retrieves the time out for a call.

Syntax

int getTimeOutForListen() const;

13.17.4 listen()

Listens for Messages on behalf of specified Agents for the amount of time specified by a previous setTimeOutForListen() call. Returns the Agent for which there is a Message.

Note that this is a blocking call. Before this call, complete the following steps:

  • Registers each Agent listener through a setAgentList() call.

  • Make a blocking call to setTimeOutForListen() that returns when a Message for one of the Agents on the list arrives. If no Messages arrive before the wait time expires, the call returns an error.

Syntax

Agent listen();

13.17.5 setAgentList()

Specifies the list of Agents for which the Listener provides its services.

Syntax

void setAgentList(
   vector<Agent>& agList);
Parameter Description 
agList

The list of Agents.

13.17.6 setTimeOutForListen()

Specifies the time out for a listen() call.

Syntax

void setTimeOutForListen(
   int waitTime);
Parameter Description 
waitTime

The time interval, in seconds, during which the Listener is waiting for Messages at specified queues.