LocalDateValidator JSR-303

CheckLocalDate.java

package training.domain;

import javax.validation.Constraint;
import javax.validation.Payload;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.time.temporal.ChronoUnit;
import java.util.concurrent.TimeUnit;

/**
 * @author sruehl
 * @version $LastChangedVersion$
 */
@Target({ElementType.METHOD, ElementType.FIELD, ElementType.ANNOTATION_TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy = LocalDateValidator.class)
@Documented
public @interface CheckLocalDate {

  public static enum Direction {
    AFTER, BEFORE
  }

  String message() default "{training.domain.localDate}";

  Class<?>[] groups() default {};

  Class<? extends Payload>[] payload() default {};

  Direction direction();

  ChronoUnit timeUnit();

  long units();
}

LocalDateValidator.java

package training.domain;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import java.time.LocalDate;
import java.time.chrono.ChronoLocalDate;
import java.time.temporal.ChronoUnit;

/**
 * @author sruehl
 * @version $LastChangedVersion$
 */
public class LocalDateValidator implements ConstraintValidator<CheckLocalDate, LocalDate> {

  private CheckLocalDate.Direction direction;

  private ChronoLocalDate chronoLocalDate;

  public void initialize(CheckLocalDate constraintAnnotation) {
    direction = constraintAnnotation.direction();
    final long d = constraintAnnotation.units();
    final ChronoUnit unit = constraintAnnotation.timeUnit();
    chronoLocalDate = LocalDate.now().minus(d, unit);
  }

  public boolean isValid(LocalDate dateToCheck, ConstraintValidatorContext constraintContext) {
    if (dateToCheck == null) {
      return true;
    }

    switch (direction) {
      case AFTER:
        return dateToCheck.isBefore(chronoLocalDate);
      case BEFORE:
        return dateToCheck.isAfter(chronoLocalDate);
    }
    throw new IllegalStateException("Unreachable code");
  }

}