Sample code for the acs-callbacks support package

• RequesterUtil
• ResponderUtil
• ResponseReceiver
  

I. The client requesting the server to call it back later

Class DemoRequester wants to invoke method revertString(), which demands a String, a CBstring, and a DescIn as its arguments. The latter two can/should be created using the RequesterUtil class. For CBstring to be created, a ResponseReceiver is necessary. A simple but in many cases sufficient example of an ResponseReceiver instance is shown below. When the Responder implementation calls the client back, the specified ResponseReceiver will be executed.

import java.util.logging.Logger;

import alma.acs.callbacks.RequesterUtil;
import alma.acs.callbacks.ResponseReceiver;
import alma.acs.commandcenter.meta.Firestarter;
import alma.acs.container.ContainerServicesBase;

import alma.mysubsystem.Responder;


public class DemoRequester {

    void go () throws Exception {

        // --- connect to component

        Firestarter.configure(null, "te1.hq.eso.org", "3500");
        Firestarter.prepare();
        ContainerServicesBase cs = Firestarter.giveContainerServices();
        Logger logger = cs.getLogger();

        Responder responder = ResponderHelper.narrow(cs.getComponent("RESPONDER"));

        // --- activate callback object
        
        ResponseReceiver rere  =  new ResponseReceiver() {
        
              public void incomingResponse(Object x) {
                 System.out.println("Incoming Response: "+x);
              }
              public void incomingException(Exception x) {
                 System.out.println("Responding failed: "+x);}
         
        };
        
        responder.revertString(  "Hallo",
                                 RequesterUtil.giveCBString(cs, rere), 
                                 RequesterUtil.giveDescIn()  );


        // --- do something else until response comes in
        
        System.out.println("--> press enter to exit <--");
        while (System.in.read() != 13)
            ;

        
        // --- clean up and quit
        
        Firestarter.godown();

    }
}

II. The server processing the request and afterwards calling back the client

Class EasyResponderImpl implements the revertString() method: after calculating the return value, it uses ResponderUtil to call the client back.

import alma.ACS.CBDescIn;
import alma.ACS.CBstring;
import alma.acs.component.ComponentImplBase;
import alma.acs.callbacks.ResponderUtil;

import alma.mysubsystem.ResponderOperations;


public class EasyResponderImpl extends ComponentImplBase implements ResponderOperations {


  public void revertString (String text, CBstring cb, CBDescIn descIn)  {

      try {

         // --- calculate returnvalue

         int length = text.length();
         char[] res = new char[length];
         for (int i=0; i<length; res[i] = text.charAt(length-1-i++));
         String returnValue = new String(res);

  
         // --- invoke callback
         
         ResponderUtil.respond (returnValue, cb, descIn);


      } catch (Exception exc) {
     
         ResponderUtil.respond (exc, cb, descIn);
      }
  
  }
 
}