###BeginCaseStudy###
Case Study: 4
Scenario 4
Application Information
You are developing a Windows Store app by using JavaScript. The app is named Print Near
Me. The app will allow mobile users to find printers in their local area that subscribe to the
Print Near Me network.
The Print Near Me app collects status data from subscribed networks, coordinates this data
with the status of printers that are listed in the central Print Near Me service, and displays the
closest locations that meet a user’s printing requirements. The locations are identified by
pinpoints on a map. The app uses a Printer Survey background task to populate the map.
The Print Here feature communicates with the central Print Near Me web server and nearby
printers, and generates custom printer interfaces based on the available printers. The printer
interfaces require complex calculations that involve repeated communications between the
app and the central web server, and may result in high memory usage.
Printer providers may indicate whether a subscribed printer is available to the network or
unavailable at any time.
Business Requirements
You have the following business requirements:
• Printer providers must have the option to approve users for each printer
through instant messaging or email.
• When a user launches the Print Near Me app, the Printer Survey task must
initiate communication between the app and the central web server to populate
the map.
• Map pinpoints must be displayed as follows:
o If the printer is available and does not require permission to print, display a
green pinpoint.
o If the printer is available and requires permission to print, display a yellow
pinpoint.
o If there is a printer or network status error, display a red pinpoint.
• Users must be able to initiate printing to a nearby printer by clicking or
tapping the printer’s pinpoint and then clicking Print Here.
Technical Requirements
You have the following technical requirements:
• The Print Here feature must run in a background process.
• The Printer Support feature must log and dispatch error messages.
o Log error messages locally.
o When the network is available, synchronize data with the central Print
Near Me web server.
• Background task events must be logged locally.

• The printer interface calculations must use the Printer Survey task for
communication to all sources.
• The Printer Survey task must push data to the app when the app is available.
Testing Requirements
You have the following testing requirements:
• Simulate user interactions in the app as part of the tests.
• Test the app performance on a variety of devices that have different
capabilities, such as processing speed and screen resolution.
• Generate a file on each device for analysis in Microsoft Visual Studio.
(Devices will not have Visual Studio installed.)
• Identify the app components that are called most frequently and that use the
most CPU resources.
• Ensure that the app detects the location of all printers and consistently reports
loss of connection.
printNearMe.js

printerSurvey.js

printDriver.js

###EndCaseStudy###

You need to implement the Print Here command.
Which code segment should you insert at line PM17?
mage:228.jpg

A.
Option A

B.
Option B

C.
Option C

D.
Option D