EntityValidator.java

package com.gr.project.util;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.logging.Logger;

import javax.enterprise.context.ApplicationScoped;
import javax.inject.Inject;
import javax.validation.ConstraintViolation;
import javax.validation.ConstraintViolationException;
import javax.validation.ValidationException;
import javax.validation.Validator;
import javax.ws.rs.core.Response;

@ApplicationScoped
public class EntityValidator {
	
	@Inject
    private Logger log;

	@Inject
    private Validator validator;
	
	
	/**
     * <p>
     * Validates the given Member variable and throws validation exceptions based on the type of error. If the error is standard
     * bean validation errors then it will throw a ConstraintValidationException with the set of the constraints violated.
     * </p>
     * <p>
     * If the error is caused because an existing member with the same email is registered it throws a regular validation
     * exception so that it can be interpreted separately.
     * </p>
     * 
     * @param member Member to be validated
     * @throws ConstraintViolationException If Bean Validation errors exist
     * @throws ValidationException If member with the same email already exists
     */
	public <T> void validateEntity(final T entity) throws ConstraintViolationException, ValidationException {
        // Create a bean validator and check for issues.
        final Set<ConstraintViolation<T>> violations = validator.validate(entity);
        
        if (!violations.isEmpty()) {
            throw new ConstraintViolationException(new HashSet<ConstraintViolation<?>>(violations));
        }
    }
	
	
	/**
     * Creates a JAX-RS "Bad Request" response including a map of all violation fields, and their message. This can then be used
     * by clients to show violations.
     * 
     * @param violations A set of violations that needs to be reported
     * @return JAX-RS response containing all violations
     */
    public Response.ResponseBuilder createViolationResponse(Set<ConstraintViolation<?>> violations) {
        log.fine("Validation completed. violations found: " + violations.size());

        Map<String, String> responseObj = new HashMap<String, String>();

        for (ConstraintViolation<?> violation : violations) {
            responseObj.put(violation.getPropertyPath().toString(), violation.getMessage());
        }

        return Response.status(Response.Status.BAD_REQUEST).entity(responseObj);
    }

}