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Case Study: 1
Scenario 1
Application Information
You are developing two Windows Store apps by using JavaScript: a Personal Trainer app and
a Client app. The apps will allow personal fitness trainers to interact with their remote clients.
Business Requirements- Personal Trainer Application
The Personal Trainer app must allow trainers to perform the following tasks:
• Create and store video and audio recordings of workout routines.
• View the profile and workout recordings for only one client at any time.
Business Requirements- Client Application
The Client app must allow clients to perform the following tasks:
• Browse a list of the trainer’s workout recordings.
• Record workouts by using the built-in webcam.
• Play, pause, restart, and stop workout recordings.
• If the capability is supported, allow the client’s webcam to pan as the client moves
around the room.
• Upload workout recordings for trainer review.
• Update their individual profiles to indicate workouts completed, calories burned, and
current weight.
The Client app must validate that the client’s subscription is valid.
Technical Requirements- General
The Client app must allow clients to perform the following tasks:
• Browse a list of the trainer’s workout recordings.
• Record workouts by using the built-in webcam.
• Play, pause, restart, and stop workout recordings.
• If the capability is supported, allow the client’s webcam to pan as the client moves
around the room.
• Upload workout recordings for trainer review.
• Update their individual profiles to indicate workouts completed, calories burned, and
current weight.
The Client app must validate that the client’s subscription is valid.
Technical Requirements- Hardware Requirements
The Personal Trainer and Client apps must support the following hardware requirements:
• Windows 8
• Webcam, microphone, and speakers
• Internet connection
While testing the apps, you identify the following issues:
• When you start the app for the first time, the system displays this warning message:
“This app needs permission to use your camera, which you can change in the app’s settings.”
• When you run the loadClientProfile( ) method in the clientData.js file, you receive an
“Access Denied” exception.
• The findCamera( ) method in the video.js file throws an exception on some devices.
• The recordVideo( ) method in the video.js file throws an exception when the device
does not support tilting.



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You need to prevent the exception that is being thrown by the findCamera( ) method.
What should you do?

A.
Check the devices collection for multiple devices.

B.
Place a try block immediately after line VD12 and a catch block immediately before line
VD17. In the catch block, display the message property of the exception object to the user.

C.
In line VD10, set the cameraID variable to null.

D.
Check the devices collection for null before setting the cameraID variable.