JTX (JSON Transform)

JTX is a Java 21 multi-module project for declarative JSON transformation. It lets you define a transformation spec and run it through a reusable engine, a CLI, or a REST API.

Modules

Path	Purpose
modules/engine	Core transformation engine and tests
modules/cli	Picocli-based command-line runner
modules/api	Spring Boot API with /v1/transform

Features

• Source-to-target JSON mapping using JSON paths
• Literal value assignment
• Built-in transforms (trim, lowercase, uppercase, to_int, concat)
• Validation with issue levels (ERROR, WARNING, INFO)
• Execution modes: STRICT and LENIENT

Requirements

• JDK 21
• Maven 3.9+

Build and Test

mvn clean verify

Engine tests only:

mvn -pl modules/engine test

CLI Usage

Sample files are provided at repository root:

• spec.json
• input.json

Run:

mvn -pl modules/cli -am exec:java \
  -Dexec.mainClass=io.github.dmesha3.jtx.cli.Main \
  -Dexec.args="--spec spec.json --in input.json --out output.json"

API Usage

Start server:

mvn -pl modules/api -am spring-boot:run

Test endpoint:

curl -X POST "http://localhost:8080/v1/transform" \
  -H "Content-Type: application/json" \
  -d '{
    "spec":"{\"version\":1,\"mode\":\"LENIENT\",\"mappings\":[{\"from\":\"$.user.id\",\"to\":\"$.id\"}]}",
    "input":{"user":{"id":"123"}}
  }'

License

This project is licensed under GNU General Public License v3.0 or later. See LICENSE for full terms.