Smart switches have been installed to monitor and automate name devices - NSC Information Technology - Question 3 - 2023 - Paper 1

The setSwitchStatus method will set the device's switch status. Define it as follows:

public void setSwitchStatus(boolean status) {
    this.fSwitchStatus = status;
}

This method will receive a Boolean value, setting the switch status accordingly.

Define the toString method to return a formatted string of all object attributes:

@Override
public String toString() {
    return String.format("Switch ID: %s\nDevice: %s\nPower usage: %s\nPower status: %s", 
        fSwitchID, fDeviceName, fPowerUsage, determineSwitchStatus());
}

Here, determineSwitchStatus() checks if the device is ON or OFF.

To extract the switchID from the combo box cmbQ3_2_1 and instantiate the SmartSwitch object, write:

// Extract switch ID
String switchID = (String) cmbQ3_2_1.getSelectedItem();

// Extract the selected device and power usage
String selectedDevice = lstQ3_2_1.getSelectedValue();
String[] parts = selectedDevice.split(" ");

String device = parts[0];
int powerUsage = Integer.parseInt(parts[1]);

// Instantiate the SmartSwitch object
SmartSwitch objSmartSwitch = new SmartSwitch(switchID, device, powerUsage);

This initializes the SmartSwitch object with the proper attributes.

To change the switch status based on the selection from the radio group, implement:

boolean status = radioGroup.isSelected() ? true : false;
objSmartSwitch.setSwitchStatus(status);

// Display the ID and status
String switchStatus = objSmartSwitch.determineSwitchStatus();
richEdit.setText(String.format("%s, %s", switchID, switchStatus));

This updates the switch status and shows it in the rich edit.

To write a date-time entry in log.txt, the following code should be used:

FileWriter writer = new FileWriter("log.txt", true);
writer.write(String.format("%s, %s, %s, %s\n",
    DateToStr(new Date()), 
    getCurrentTime(),
    objSmartSwitch.getSwitchID(), 
    objSmartSwitch.determineSwitchStatus()));
writer.close();

This appends the required information into the log file.

For the power usage calculation, use:

int hours = Integer.parseInt(edtQ3_2_4.getText().toString());
double energyUsed = objSmartSwitch.energyUsed(hours);

// Display the result
richEdit.setText(String.format("Energy used: %.2f kWh", energyUsed));

This retrieves the user-inputted hours and displays the energy used in kilowatt-hours.