DS sample to manage multiple references (SLING-2575)

MultiplexingAuthorizableAction.java

import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.concurrent.ConcurrentSkipListMap;

import javax.jcr.*;

import org.apache.felix.scr.annotations.*;
import org.apache.jackrabbit.api.security.user.*;
import org.apache.jackrabbit.core.security.user.action.AbstractAuthorizableAction;
import org.apache.jackrabbit.core.security.user.action.AuthorizableAction;
import org.apache.sling.commons.osgi.ServiceUtil;
import org.slf4j.*;

@Component
@Service(value = AuthorizableAction.class)
@Reference(name = "AuthorizableAction",
        policy = ReferencePolicy.DYNAMIC,
        cardinality = ReferenceCardinality.OPTIONAL_MULTIPLE,
        referenceInterface = AuthorizableAction.class
)
public class MultiplexingAuthorizableAction extends AbstractAuthorizableAction{
    private Logger log = LoggerFactory.getLogger(getClass());
   /**
    * The map entries are sorted on Service ranking in descending order. So the action instance with higher 
    * ranking would be invoked first
    */
    private Map<Comparable<Object>,AuthorizableAction> actionMap = 
                      new ConcurrentSkipListMap<Comparable<Object>, AuthorizableAction>(Collections.reverseOrder());

    public void onCreate(User user, String password, Session session) throws RepositoryException {
        log.info("Created user {}", user.getID());
        for(AuthorizableAction a : getActions()){
            a.onCreate(user,password,session);
        }
    }
    
    @Deactivate
    private void deactivate(){
        actionMap.clear();
    }

    private Collection<AuthorizableAction> getActions() {
        return actionMap.values();
    }

    private void bindAuthorizableAction(AuthorizableAction action,Map<String,Object> config){
        actionMap.put(ServiceUtil.getComparableForServiceRanking(config), action);
    }

    private void unbindAuthorizableAction(AuthorizableAction action,Map<String,Object> config){
        actionMap.remove(ServiceUtil.getComparableForServiceRanking(config));
    }


}