/**
* Returns the optimal next action to taken based on future knowledge. The first element of the
* context array should be the time. That is the time when the user needs to make a decision. It
* could be the current time for the user or some time in the future.
*
* <p>StepOptimalScheduler looks one step into the future and returns the optimal decision in the
* first element of the returned array based on the current NIC state:
*
* <ul>
* <li>If the current stat is WiFiNIC.OFF, then the command is WiFiNIC.ON
* <li>If the current state is WiFiNIC.DISCONNECTED, then the command is WiFiNIC.CONNECTED and
* also contains the BSSID of the AP to connect in the second element.
* <li>If the current state is WiFiNIC.CONNECTED, then the command will be WiFiNIC.DATA_TX.
* </ul>
*
* @param context the state of the WiFiNIC
* @return the optimal COMMAND and the BSSID if action is ASSOCIATE
* @throws SchedulerException if the medium is not available at the requested time
*/
public ArrayList query(ArrayList context) throws SchedulerException {
now = (Double) context.get(0);
Log.debug(this, "Query " + context);
if (!medium.hasTime(now))
throw new SchedulerException("The medium is not available at time " + now);
if (context.size() < 2) throw new SchedulerException("Malformed context array");
int niccondition = (Integer) context.get(1);
HashSet futurestatus = (HashSet) medium.scan(now);
ArrayList<Object> command = new ArrayList<Object>(3);
command.add(NIC.WiFi);
if (futurestatus == null) {
command.add(WiFiNIC.NOP);
}
if (futurestatus.size() == 0) {
command.add(WiFiNIC.NOP);
}
if (niccondition == WiFiNIC.OFF) {
command.add(WiFiNIC.ON);
}
if (niccondition == WiFiNIC.DISCONNECTED) {
command.add(WiFiNIC.CONNECTED);
command.add(findNextAP(futurestatus));
}
if (niccondition == WiFiNIC.CONNECTED) {
command.add(WiFiNIC.DATA_TX);
command.add(endtime);
}
/* If the user is connected to an AP, just check if it will be available and return DATA_TX */
Log.debug(this, "Command " + command);
return command;
}
/**
* Initializes the scheduler. An optimal scheduler does not have much to do in terms of
* initialization but this method should still be called before any other method of the scheduler
* is called.
*
* @param goal data transmission goal of the scheduler
* @param energysens energy sensitivity of the scheduler
* @param delaysens delay sensitivity of the scheduler
*/
public void initialize(double goal, double energysens, double delaysens) {
Log.info(this, "initializing");
}
