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@Target(value={FIELD,PARAMETER})
@Retention(value=RUNTIME)
@Documented
public @interface Delegate
Identifies the delegate injection point of a decorator. May be applied to a field, bean constructor parameter or initializer method parameter of a decorator bean class.
 @Decorator 
 class TimestampLogger implements Logger { 
    @Inject @Delegate @Any Logger logger; 
    ... 
 } 
 
 
 @Decorator 
 class TimestampLogger implements Logger { 
    private Logger logger;
    
    @Inject
    public TimestampLogger(@Delegate @Debug Logger logger) { 
       this.logger=logger; 
    } 
    ... 
 } 
 
 
 A decorator must have exactly one delegate injection point. The delegate injection point must be an injected field, initializer method parameter or bean constructor method parameter.
The container injects a delegate object to the delegate injection 
 point. The delegate object implements the delegate type and delegates 
 method invocations along the decorator stack. When the container calls 
 a decorator during business method interception, the decorator may 
 invoke any method of the delegate object. If a decorator invokes the 
 delegate object at any other time, the invoked method throws an 
 IllegalStateException.
 @Decorator 
 class TimestampLogger implements Logger { 
    @Inject @Delegate @Any Logger logger; 
    
    void log(String message) {
       logger.log( timestamp() + ": " + message );
    }
    ...
 } 
 
@Decorator specifies that a
 class is a decorator.
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