Complex Expression Evaluator

API that evaluates expressions defined with a custom grammar. Uses ANTLR library to generate a parser. Expressions can use paths to values contained in the provided JSON document.

Implementation details:

• Java 21
• Spring Boot Framework
• JPA with H2 database
• Maven

Endpoints

• POST /expression

   {
   	"name": "Last name and home implies 127.0.0.1",
   	"value": "user.last_name == \"Katalenić\" && (user.addresses[0].label != \"home\" OR user.addresses[0].address == \"127.0.0.1\")"
   }

• GET /expressions
• POST /evaluate?expressionId=<expression_id>

   {
   	"user": {
   		"first_name": "Ivan",
   		"last_name": "Katalenić",
   		"addresses": [
   			{
   				"label": "home",
   				"address": "127.0.0.1"
   			}
   		]
   	}
   }

Swagger UI for the OpenAPI documentation is available at http://localhost:8080/swagger-ui/index.html, while documentation in JSON format is available at http://localhost:8080/api-docs.

Commands

Run

mvn clean spring-boot:run

Generate the parser code

mvn generate-sources

This isn't needed specifically as it will be done automatically when running. The code will be in the target directory.