Question

I have 3-tier EJB application, and I need to create a view on a thick client (desktop Java application) that shows a very large collection of objects (over 5000 orders). Each object has child properties that are also complex objects, for example:

class Address
{
 String value 
 // other properties
}

class Order
{
 public String Number

 // this is collection of complex object and I need first and last object to show it's
 // properties in view
 public List<Address> getAddresses()

 // other properties
}

The view is a table of Orders:

Number | FirstAddress | LastAddress | …

My first attempt was to load full List of orders (without child properties) and then dynamically download child objects when needed for display. But when I have 10000 orders and begin fast scrolling, the UI become unresponsive.

Then I try to load all orders and all children that need to be shown in the table, but the UI gets very heavy and slow, possibly because of memory cost). And it’s not thick client at all, because I download almost all data from db.

What is best practice to solve this task?

Answer 1

Assuming you are using a JTable as the view of a suitable TableModel, query the database using a SwingWorker and publish() the results as they arrive. For simplicity, this example simply fetches random data in blocks of 10. Note that the UI remains responsive as data accumulates.