Encapsulating common exception handling logic

Question

I have a series of web service method calls which all follow the below format. The only difference in each method is httpRequest.methodName(). Can anybody think of a way I can encapsulate the common logic? Also note that my environment is J2ME.

public Response webserviceCall(Request request) {

    HTTPRequest httpRequest = new HTTPRequest(new ConnectionProperties());

    String errorMessage = "";
    String errorCode = "";

    try {
        // the only thing different
        httpRequest.methodName();
    } catch (SDKException e) {
        errorMessage = e.getMessage();
        errorCode = e.getErrorCode();
    }

    Error error = new Error(errorMessage,errorCode);

    return new Response(error);
}

Answer 1

One alternative is to put that code in an abstract class, and change it to call an abstract method (name it process, for example):

abstract class BaseWebService {
   public abstract Response process(HTTPRequest request) throws SDKException;

   public Response webserviceCall(Request request) {

       HTTPRequest httpRequest = new HTTPRequest(new ConnectionProperties());

       String errorMessage = "";
       String errorCode = "";

       try {
           process(httpRequest);
       } catch (SDKException e) {
           errorMessage = e.getMessage();
           errorCode = e.getErrorCode();
       }

       Error error = new Error(errorMessage,errorCode);

       return new Response(error);
   }
 }

Then make each of your services extend that class and implement the process method as needed

class OneService extends BaseWebService {

   Response process(HTTPRequest request) throws SDKException{
        return request.methodName();
   } 
}

For the records, this is the Template Method Pattern