package ejava.jpa.example.validation;
   
   import java.lang.annotation.Documented;
   import java.lang.annotation.Retention;
   
   import java.lang.annotation.Target;
   import static java.lang.annotation.ElementType.*;
   import static java.lang.annotation.RetentionPolicy.*;
   import javax.validation.Constraint;
  import javax.validation.Payload;
  
  /**
   * Defines a constraint annotation for expressing a minimum age.
   */
  @Documented
  @Constraint(validatedBy={MinAgeValidator.class})
  @Target({METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER})
  @Retention(RUNTIME)
  public @interface MinAge {
  	String message() default "too young";
  	Class<?>[] groups() default {};
  	Class<? extends Payload>[] payload() default{};
  	int age();
  	
  	/**
  	 * Defines an array of annotations so that more than one can be applied.
  	 */
  	@Target({METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER})
  	@Retention(RUNTIME)
  	@Documented
  	public @interface List {
  		MinAge[] value();
  	} 
  }