CrossFieldValidator.java

package dk.xakeps.truestarter.server.validator;

import org.apache.commons.beanutils.PropertyUtils;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import javax.validation.ValidationException;
import java.lang.reflect.InvocationTargetException;

public class CrossFieldValidator implements ConstraintValidator<CrossField, Object> {
    private String[] fields;

    @Override
    public void initialize(CrossField constraintAnnotation) {
        this.fields = constraintAnnotation.fields();
    }

    @Override
    public boolean isValid(Object value, ConstraintValidatorContext context) {
        Object prevFieldValue = null;
        int i = 0;
        for (String field : fields) {
            try {
                Object property = PropertyUtils.getProperty(value, field);
                if (i == 0) {
                    prevFieldValue = property;
                    i++;
                    continue;
                }
                if (!prevFieldValue.equals(property)) {
                    return false;
                }
                prevFieldValue = property;
                i++;
            } catch (IllegalAccessException | InvocationTargetException | NoSuchMethodException e) {
                throw new ValidationException("Failed validating bean", e);
            }
        }
        return true;
    }
}