API Hex Translation

Assumptions

• As per the examples, byte position is left to right.
• The keys are 7 characters wide (i.e. 28 bits) - should they be 8 (32 bits)? (Assuming 7 as there are 3 and all are.)

Goal

Using Java, create a REST based endpoint that will accept a JSON payload being POST with hexadecimal encoded key/value pairs and convert the content into a different JSON structure that is more developer friendly using the provided data dictionary.

Technology assumptions

• API implementation must be performed in Java
• Libraries may be used to assist with the implementation
• Provided data dictionary specifies how to intrepret the hex data

Task

A JSON payload with a key and value parameter is passed as an HTTP POST payload to an endpoint.

The implementation shall take that input and use the provided data dictionary below.

JSON payload shall be returned representing the decoded data in an easier to read form based on the data dictionary.

In Scope:

• Parsing and basic input validation on input JSON payload
• Parsing data using data Dictionary (support to parse all 3 keys each returning different response payload)
• Generating output JSON payload

Out of Scope:

• Support additional data types not specified in data dictionary
• Support parsing additional keys not provided

Example Request

curl --location --request POST 'http://localhost:8080/parse' \
--header 'Content-Type: application/json' \
--data-raw '{"key": "0000001", "value": "01"}'

Example Response

{"door_status": "open"}

Data Dictionary

Key: 0000001

Name: Door Status

Length: 1 byte

Byte Position	Bit Position	Name	Type	Details
0	-	Door status	Enum / UInt8	0: Closed 1: Open

Example: An open door would report a value of "01"

Key: 0000002

Name: Cooking Notifications

Length: 1 byte

Byte Position	Bit Position	Name	Type	Details
0	0	Target Temperature Achieved	bit
0	1	Cooking Started	bit
0	2	Cooktime One Minute Remaining	bit
0	3	Cooking Complete	bit
0	4-7	n/a	unused

Example: A cooking started notification would report "02"

Key: 0000004

Name: Current Cooking Parameters

Length: 11 bytes

Byte Position	Bit Position	Name	Type	Details
0	-	Shade	UInt8
1	-	Size	Enum/UInt8	0: Small 1: Medium 2: Large
2-3	-	Temperature (F)	UInt16
4-7	-	Cook Time (Seconds)	UInt32
8	-	Count	UInt8
9	-	Cook Mode	Enum/UInt8	0: Air Fry 1: Bake 2: Broil 3: Roast 4: Reheat 5: Warm 6: Slow Cook 7: Dehydrate 8: Proof 9: Cookie 10: Pizza 11: Bagel 12: Toast 13: Crisp Finish 14: Cake 15: Cookie with Preference 16: Pizza with Preference
10	-	Preferences	UInt8
11	-	n/a	unused

Example: Air Fry a small size at 400 degrees for 1200 seconds would report "00000190000004B000000000"

Guidelines

• Focus is on decoding the binary data to JSON, not the REST endpoint

Submission

• Submit complete program via github.com repo (or zip file) back to the interviewer
  • Email program 24 hours prior to follow-up interview
• Solution is expected to take ~1-2 hours to implement
• Demonstrate solution in follow-up interview
• Remember, the key word is 'Idempotence'