code: protected IDFComponentDescription[] getReceivers(String target_service) {
          // Search for X_Service
          // Create a service description to search for.
          IDF df = (IDF) SServiceProvider.getService(getServiceContainer(),
                  IDF.class, RequiredServiceInfo.SCOPE_PLATFORM).get(this);
          IDFServiceDescription sd = df.createDFServiceDescription(
                  target_service, null, null);
          IDFComponentDescription dfadesc = df.createDFComponentDescription(null,
                  sd);
  
          ISearchConstraints constraints = df.createSearchConstraints(-1, 0);
  
          // Use a subgoal to search
          IGoal ft = createGoal("dfcap.df_search");
          ft.getParameter("description").setValue(dfadesc);
          ft.getParameter("constraints").setValue(constraints);
          ft.getParameter("leasetime").setValue(new Long(LEASE_TIME));
  
          dispatchSubgoalAndWait(ft);
  
          return (IDFComponentDescription[]) ft.getParameterSet("result")
                  .getValues();
      }
docs: This method will be used to know the IDFComponentDescription of all the
  agents that own a df_service. Given the IDFComponentDescription, the name
  of the agent is known using getName()
  
  @param target_service
  The name of the df_service
  @return Its agent IDFComponentDescription