Projector Management System

What is it?

• A RESTful projector management system that allows teams to reserve projectors, update their reservations, cancel their reservations, and also check the availability of projectors.

• Projector bookings can be one time or recurring. A recurring booking is indicated by its first time slot, which contains the information about recurrence interval and the end time when recurrence should stop. For non-recurring bookings, the recurrence interval is set to 0, and end time field is irrelevant.

• The projector only grants a recurring meeting, if all possible instances of the meeting (in the current year) can be scheduled on a single projector.

• The implementation uses a list of RangeSets (or Interval Trees) to keep track of booked time slots for the current year. When a new POST request is received to reserve a slot, these datastructures are consulted, and if an allocation is possible then it is made. DB is updated accordingly.

• If a projector cannot be assigned for the requested slot then the system will suggest next start time when a projector is available. However, next start time is only suggested for non-recurring meetings. If a recurring meeting slot cannot be assigned a projector, system will not suggest another time.

• Suppose Team 1 would like to reserve a projector starting from 1PM July 3rd 2017, and they'd like to reserve it for 1 hour.

  • A projector can be reserved by sending a POST request to /projector/request with the following JSON content:

   {
   "startDateTime":"2017-07-03T13:00:00.00Z",
   "duration":3600000,
   "recurInterval":0,
   "recurEndDateTime":"2017-08-01T00:00:00.00Z",
   "teamID":1
   }

  • The above booking would start on July 3rd 2017 at 1:00PM(startDateTime) and will last for 1 hour(Duration in milliseconds). recurInterval = 0 indicates that this is a one time meeting.

• If the team would like to reserve this projector at this time every 3 days, the POST request should contain the following JSON:

  {
  "startDateTime":"2017-07-03T13:00:00.00Z",
  "duration":3600000,
  "recurInterval":259200000,
  "recurEndDateTime":"2017-08-01T00:00:00.00Z",
  "teamID":1
  }

  • The above booking will start on July 3rd 2017 at 1:00PM (as indicated by startDateTime), each session would last 1 hour(duration in milliseconds), and it would recur every 3 days(recurInterval in milliseconds) till 1st August 2017 (recurEndDateTime)

  • If the allocation was successful below JSON would be returned

     {
     	"projectorID":0,
     	"allocatedID":4
     }

  • if allocation fails, below JSON would be returned

     {
         "allocatedID":-1
     }

• if the team would now like to update their booking then they can do so by sending a PUT request to /projector/update with the following JSON:

  {
     "allocationID":7,
     "startDateTime":"2017-07-03T15:00:00.00Z",
     "duration":0,
     "recurInterval":259200000,
     "recurEndDateTime":"2017-08-01T00:00:00.00Z"
  }

  • Where allocationID points to the booking that needs to be changed

• To delete a booking send a DELETE request to '/projector/delete` with following JSON:

   {
   	"allocationID":3
   }	

• To get the schedule of a particular projector send a GET request to /projector/status/0 .This will return the schedule of projector 1(index 0)

Dependencies

Written in Java, using Spark framework(http://sparkjava.com/) and SQLite 3.3+ as DB

Other dependencies are:

• JDBC SQLite driver
• slf4j api
• org.json api
• Google guava RangeSet
• JUnit

Building and Executing

This a maven project, all the dependencies will be handled by maven. Use the following commands:

• mvn test - Executes basic tests on the app

• mvn -e exec:java -Dexec.mainClass="App" - Will build and execute the app

• mvn clean package = Generates 2 jar files under target. jar-with-dependencies can be executed as it includes all the dependencies

  • The resulting jar can be executed as java -cp target/LeanTaasCodingTest-1.0-SNAPSHOT-jar-with-dependencies.jar App

• App will run on localhost:4567