FibServer

Overview

This program is a simple Spring Boot application that calculates and returns numbers from the Fibonacci sequence.

It provides 3 REST endpoints using HTTP GET (on port 8080):

• /current -- returns the current number in the Fibonacci sequence. The returned payload is JSON, eg: {"fibonacci":55}
• /next -- calculates and returns the next number in the sequence. As above, the returned payload is JSON. If the next number would overflow a Java long, an error is returned: {"status":400,"path":"/next","errorMessage":"Bad Request. Number would overflow Java long datatype.","timeStamp":"Sat Oct 10 12:07:23 EDT 2020"}
• /previous -- calculates and returns the previous number in the sequence. If the current number in the sequence is 0, this call returns an error: {"status":400,"path":"/previous","errorMessage":"Bad Request. No previous number in the Fibonacci sequence.","timeStamp":"Sat Oct 10 12:35:21 EDT 2020"}

Since the program is only maintaining one sequence (not one per client application), there may be gaps in the sequence when multiple programs are accessing the endpoints.

Download, Compile, Run

git clone http://github.com/rcprcp/FibServer.git 
cd FibServer
mvn clean package spring-boot:repackage

Test

You can run the tests from mvn:

mvn test 

or

mvn test -Dtest=TestFibonacci
mvn test -Dtest=TestSaveRestoreUsingFile

Note: The restart "state" is found in ./checkpoint.data - remove this file to start the Fibonacci sequence from 0.

Start the server: java -jar target/fibserver-0.0.1-SNAPSHOT.jar

The server opens port 8080.

If desired, test it from your browser:

http://localhost:8080/current
http://localhost:8080/next
http://localhost:8080/previous