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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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Copyright © 2009 Sun Microsystems, Inc. All Rights Reserved. Use is subject to license terms.
Generated on 24-November-2009 03:24