Annotations

Question 1

Retence anotace - syntax, druhy (3)

Answer 1

@Retention(RetentionPolicy.RUNTIME)
source
class
runtime

Question 2

Target anotace - syntax, druhy (11)

Answer 2

@Target(ElementType.METHOD, ElementType.FIELD)
annotation_type
field, local_variable, parameter
method, constructor
package, module
type, type_parameter, type_use

Question 3

Dedicnost anotaci

Answer 3

Nededi se, ale lze vynutit pomoci @Inherited

Question 4

Anotace v javadocu

Answer 4

@Documented - vypise se do javadocu

Question 5

Anotace, ktera se muze opakovat - definice, pouziti

Answer 5

@Repeatable(Ann1.class)
public @interface Ann2 { … }

@Ann1({@Ann2, @Ann2})

Question 6

Elementy anotace - jake muzou byt druhy? (5)

Answer 6

primitive, String, class, enum
array cehokoli z toho

Question 7

Zapis anotace s retention, target, elementem s a bez hodnoty, array elementem

Answer 7

@Retention(RetentionPolicy.SOURCE)
@Target(ElementType.FIELD)
public @interface MyAnnotation {
int field1() default 0;
int field2();
int[] field3;
}

Question 8

Pouziti anotace - zapis hodnot array (1), zapis pro anotaci s jedinym elementem (2)

Answer 8

@Ann(element = {“a”, “b”})

@Ann(element = value)
@Ann(value)

Question 9

Deprecation: anotace, javadoc anotace

Answer 9

@Deprecated(since=”11”, forRemoval=true)
@deprecated

Question 10

Potlaceni syntax warningu anotaci
castovani
pouziti deprecated metody
pretypovani varargs (heap pollution)

Answer 10

@SuppressWarnings(“unchecked”, “deprecation”)
@SafeVarargs + metoda bud private nebo final

Question 11

Reflection - ktere anotace nejdou reflexi zjistit?
anotace tridy (2)
anotace - ziskej typ a elementy

Answer 11

source
class.getAnnotations(), getAnnotationsByType(Ann.class)
a.getAnnotationType()
a.jmenoElementu()