Filters and Interceptors - RESTful Java with JAX-RS 2.0 - page 186

import import javax.ws.rs.container.DynamicFeature javax.ws.rs.container.DynamicFeature ;

import import javax.ws.rs.container.ResourceInfo javax.ws.rs.container.ResourceInfo ;

import import javax.ws.rs.core.FeatureContext javax.ws.rs.core.FeatureContext ;

@Provider
public public class class MaxAgeFeature MaxAgeFeature implements implements DynamicFeature {

public public void void configure ( ResourceInfo ri , FeatureContext ctx ) {

MaxAge max = ri . getResourceMethod (). getAnnotation ( MaxAge . class );
iif ( max == null

return ;
CacheControlFilter filter = new

null ) return

new CacheControlFilter ( max . value ());

ctx . register ( filter );

}

}

The MaxAgeFeature.configure() method is invoked for every deployed JAX-RS resource
method. The configure() method first looks for the @MaxAge annotation on the Re-
sourceInfo 's method. If it exists, it constructs an instance of the CacheControlFilter ,
passing in the value of the @MaxAge annotation. It then registers this created filter with the
FeatureContext parameter. This filter is now bound to the JAX-RS resource method repres-
ented by the ResourceInfo parameter. We've just created a JAX-RS extension!

Name Bindings

The other way to bind a filter or interceptor to a particular JAX-RS method is to use the
@NameBinding meta-annotation:

package package javax . ws . rs ;

import import java.lang.annotation.Documented java.lang.annotation.Documented ;

import import java.lang.annotation.ElementType java.lang.annotation.ElementType ;

import import java.lang.annotation.Retention java.lang.annotation.Retention ;

import import java.lang.annotation.RetentionPolicy java.lang.annotation.RetentionPolicy ;

import import java.lang.annotation.Target java.lang.annotation.Target ;

@Target ( ElementType . ANNOTATION_TYPE )
@Retention ( RetentionPolicy . RUNTIME )
@Documented
public public @interface NameBinding {

}

You can bind a filter or interceptor to a particular annotation and when that custom annota-
tion is applied, the filter or interceptor will automatically be bound to the annotated JAX-RS