Evaluation Microservice

This microservice provides evaluation functionality for products using Spring Expression Language (SpEL) and Thymeleaf templates.

Features

SpEL Evaluations: Validate and compute product properties using trusted SpEL expressions.
Thymeleaf Template Evaluations: Generate dynamic strings based on product data with Thymeleaf templates.
Configuration Driven: Template caching is configurable via YAML with Spring IDE metadata for auto-completion.
Robust Error Handling: Critical failures in SpEL and template evaluations are logged at the ERROR level, and unresolved template variables raise a custom exception.
Unit Testing: Tests are written with Mockito and bootstrapped with a dedicated test configuration.

Directory Structure

.
├── pom.xml
├── src
│   ├── main
│   │   ├── java
│   │   │   └── org
│   │   │       └── open4goods
│   │   │           └── evaluation
│   │   │               ├── config
│   │   │               │   └── EvaluationProperties.java
│   │   │               ├── exception
│   │   │               │   └── TemplateEvaluationException.java
│   │   │               └── service
│   │   │                   └── EvaluationService.java
│   │   └── resources
│   └── test
│       ├── java
│       │   └── org
│       │       └── open4goods
│       │           └── evaluation
│       │               └── service
│       │                   └── EvaluationServiceTest.java
│       └── resources
│           └── application-test.yml

Configuration

The microservice reads its configuration from YAML files. In particular, the template caching property is configured via:

evaluation:
  template:
    cacheable: true

This property controls whether Thymeleaf template caching is enabled. IDE metadata is provided for enhanced Spring configuration support.

How to Build

Use Maven to build the project:

mvn clean install

Running

Run the microservice as a Spring Boot application using your preferred method.

How to Use

The EvaluationService is a Spring-managed service that can be injected into your controllers or other services. Here are some example usages:

import org.open4goods.services.evaluation.service.EvaluationService;
import org.open4goods.services.evaluation.exception.TemplateEvaluationException;
import org.open4goods.model.product.Product;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class ProductController {

    private final EvaluationService evaluationService;

    @Autowired
    public ProductController(EvaluationService evaluationService) {
        this.evaluationService = evaluationService;
    }

    public void evaluateProduct(Product product) {
        // Evaluate a condition using SpEL (e.g., check if the product price is greater than 100)
        boolean isValid = evaluationService.spelEval(product, "p.price > 100");
        System.out.println("Product valid: " + isValid);

        // Compute a string value using SpEL (e.g., generate a product identifier)
        String computedId = evaluationService.spelCompute(product, "'Product-' + p.id");
        System.out.println("Computed Product ID: " + computedId);

        // Evaluate a Thymeleaf template using product data
        try {
            String evaluatedTemplate = evaluationService.thymeleafEval(product, "Product Name: [[${p.name}]]");
            System.out.println(evaluatedTemplate);
        } catch (TemplateEvaluationException ex) {
            // Handle unresolved variable exception
            System.err.println("Error evaluating template: " + ex.getMessage());
        }
    }
}

You can also pass a map of additional parameters to the Thymeleaf evaluation:

Map<String, Object> params = new HashMap<>();
params.put("customMessage", "Welcome to our product service!");
String result = evaluationService.thymeleafEval(params, "Message: [[${customMessage}]]");
System.out.println(result);

Testing

Unit tests are provided in the src/test directory. To run tests, execute:

mvn test

Logging

Critical failures in SpEL and Thymeleaf evaluations are logged at the ERROR level for better traceability.

Contributing

Contributions are welcome. Please ensure that any new code is accompanied by appropriate unit tests and documentation.