package com.atlassian.plugins.rest.module;
   
   import com.google.common.base.Preconditions;
   import com.sun.jersey.api.model.AbstractMethod;
   import com.sun.jersey.spi.container.ResourceFilter;
   import com.sun.jersey.spi.container.ResourceFilterFactory;
   import org.osgi.framework.BundleContext;
   import org.osgi.framework.ServiceReference;
   
  import java.util.Collections;
  import java.util.List;
  
  /**
   * A resource filter factory that takes care of looking up the underlying {@link ResourceFilterFactory} from the given {@link ServiceReference}
   */
  class OsgiServiceReferenceResourceFilterFactory implements ResourceFilterFactory {
      private final BundleContext bundleContext;
      private final ServiceReference serviceReference;
  
      OsgiServiceReferenceResourceFilterFactory(final BundleContext bundleContext, final ServiceReference serviceReference) {
          this.bundleContext = Preconditions.checkNotNull(bundleContext);
          this.serviceReference = Preconditions.checkNotNull(serviceReference);
      }
  
      public List<ResourceFilter> create(final AbstractMethod am) {
          final ResourceFilterFactory resourceFilterFactory;
          try {
              resourceFilterFactory = (ResourceFilterFactory) bundleContext.getService(serviceReference);
          } catch (ClassCastException e) {
              throw new IllegalStateException("The service registered should be an instance of " + ResourceFilterFactory.class, e);
          }
  
          return resourceFilterFactory != null ? resourceFilterFactory.create(am) : Collections.<ResourceFilter>emptyList();
      }
  }