Question

I have a web application developped in Java 1.5 with Spring framework. Application contains “dashboards” which are simple pages where a bunch of information are regrouped and where user can modify some status. Managers want me to add a logging system in database for three of theses dashboards. Each dashboard has different information but the log should be traced by date and user’s login.

What I’d like to do is to implement the Strategy pattern kind of like this :

interface DashboardLog {
   void createLog(String login, Date now);
}

// Implementation for one dashboard
class PrintDashboardLog implements DashboardLog {
  Integer docId;
  String status;

  void createLog(String login, Date now){
    // Some code
  }
}

class DashboardsManager {
  DashboardLog logger;
  String login;
  Date now;

  void createLog(){
     logger.log(login,now);
  }
}

class UpdateDocAction{
   DashboardsManager dbManager;

   void updateSomeField(){
      // Some action
      // Now it's time to log
      dbManagers.setLogger = new PrintDashboardLog(docId, status);
      dbManagers.createLog();
   } 
}

Appcontext.xml :

<bean id="dashboardManagers" class="...DashboardManagers" />

In this solution I’m therefore not using dependency injection. Is it “correct” (good practice, performance, …) to do it this way ? Is there a better way where I could use DI ?

Note :I did not write basic stuff like constructors and getter/setter.

Answer 1

While it is perfectly “correct” to employ the strategy pattern as you have, but considering the fact that you’re using Spring – it would be better to employ the Dependency Injection mechanism provided by the Spring framework – might as well put to use what your framework has to offer as one of its core strengths.