Java Reference
In-Depth Information
LISTING 6‐27: LongMessage implementation of message interface
public class LongMessage implements MessageType {
private String message;
public String getMessage() {
return message;
public void setMessage(String message) {
this.message = message;
Each concrete implementation of the MessageType interface, as shown in Listing 6-25, is annotated
with an @Message qualii er denoting the message type as either Message.Type.SHORT or Message
.Type.LONG as implemented in Listing 6-26 and Listing 6-27 respectively. The @Message qualii er is
implemented in the same manner, as can be seen is Listing 6-28, as the qualii er used in the Custom
Annotation Type example shown earlier.
LISTING 6‐28: Custom message annotation
@Target({ElementType.FIELD, ElementType.TYPE})
public @interface Message {
Type value();
enum Type{ SHORT , LONG }
To create the annotation literal that you use to make the comparison between the type you want
and the type of the dependency, you extend the abstract class AnnotationLiteral and implement
Message as the custom message qualii er. Listing 6-29 shows how this is done.
LISTING 6‐29: Annotation literal used to retrieve required message type
public class MessageLiteral extends AnnotationLiteral<Message> implements Message {
private static final long serialVersionUID = 1L;
private Type type;
public MessageLiteral(Type type) {
this.type = type;
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