How to do a custom validation using members from the same class?

[agramajoL]

For example:

Class A {
 int a;
 int b;
}

And I want to validate that

a <= b

[marcosolina]

Try this

public class A {
 int a;
 int b;
}

public YourValidator extends AbstractValidator{
  public void rules() {
    ruleFor(c -> c)
            .must(c -> c.a <= c.b)
            .... other stuff
  }
}

[mvallim]

Hi @agramajoL,

Example:

class A

public class A {

  private int a;

  private int b;

  private A(final int a, final int b) {
    this.a = a;
    this.b = b;
  }

  public int getA() {
    return a;
  }

  public void setA(final int a) {
    this.a = a;
  }

  public int getB() {
    return b;
  }

  public void setB(final int b) {
    this.b = b;
  }

}

class AValidador

import static br.com.fluentvalidator.function.FunctionBuilder.of;
import static br.com.fluentvalidator.predicate.ComparablePredicate.lessThanOrEqual;

import br.com.fluentvalidator.AbstractValidator;

import static java.util.function.Function.identity;

public static class AValidador extends AbstractValidator<A> {

  @Override
  public void rules() {

    ruleFor(identity())
      .must(lessThanOrEqual(of(A::getA), of(A::getB)));

  }

}

class SampleTest

import static org.hamcrest.Matchers.equalTo;
import static org.junit.Assert.assertThat;

import org.junit.Test;

import br.com.fluentvalidator.Validator;
import br.com.fluentvalidator.context.ValidationResult;

public class SampleTest {

  private final Validator<A> validator = new AValidador();

  @Test
  public void testSuccessLessThanCompare() {
    final A a = new A(1, 2);

    final ValidationResult validationResult = validator.validate(a);

    assertThat(validationResult.isValid(), equalTo(true));
  }

  @Test
  public void testSuccessLessThanOrEqualCompare() {
    final A a = new A(1, 1);

    final ValidationResult validationResult = validator.validate(a);

    assertThat(validationResult.isValid(), equalTo(true));
  }

  @Test
  public void testFailLessThanCompare() {
    final A a = new A(2, 1);

    final ValidationResult validationResult = validator.validate(a);

    assertThat(validationResult.isValid(), equalTo(false));
  }
}

Thanks for sharing your question.

Best regards,