将我的公司登录名放在vaadin应用程序中的位置

Question

I have a small vaadin application which would allow users to input some data in a form (employee details like name, surname, address etc) and store each employee object in a List. This is the structure so far:

EmployeeForm
    src/main/java
        com.vaadin.project.EmployeeForm
            MyUI.java
        employee
            Address.java
            Employee.java

So, for testing purposes I created an Employee object directly inside MyUI.java, like so:

Address address1 = new Address(34, "Flinch Street","KT25AG");
Employee employee1 = new Employee("John","Smith", "Male", 39, address1, "Permanent", 8765);
List<Employee> employee = new ArrayList<Employee>();
employee.add(employee1);
for(Employee currentEmployee : employee ){
    System.out.println(employee);
}

just to make sure things works, but it seems wrong to do that there, so I'd like to create another class that deals with all the business logic, and I was wondering what the best way would be. By business login I mean that What I need to make sure it happens is that after users fill in the form on the MyUI.java file and click the submit button a new Employee object is created and stored in a List. So I'm thinking, can I have a function call in MyUI.java, something like createNewEmployee() and then have that function defined inside another class CreateEmployee.java , get all the data I need (name, surname, address etc) from MyUI.java and construct the new Employee object in CreateEmployee.java ? Does that sound reasonable? It's easy enough to do that inside the MyUI.java but I reckon that should only deal with the GUI, what do you guys think?

Answer 1

I like to use a service design pattern where all business logic is encapsulated in services.

You would have an EmployeeService class that in the simplest form could be instantiated as a member variable on your MyUI. My services are usually stateless and have business methods. In your example it would have the method called createNewEmployee().

I typically like to have an interface for my services. Some people use an additional layer for any data source interaction (search for DAOs). I like to keep it simple and access the data sources directly from my service.

If I think I'm going to have a multiple implementations or have need to swap out data sources in the future then I would have an AbstractEmployeeService where most of the true business logic would go and then have a data source specific implementation of that to do data source interaction (for example a JdbcEmployeeService.)

If you want to get more advanced, I'd recommend using Spring to inject your services. See http://vaadin.github.io/spring-tutorial/ to get a start.

Different developers will have different opinions. There is no one right answer, but you are on the right path to separate our your business logic!