Architecture of Application

General
1

I am evaluating Vaadin for a product I am working on. I am quite familiar with Swing so as I have been running through prototypes I’ve been finding myself doing things in a Swing like manner. For example, I’ve been playing around with creating a Master/Detail type page where I have a master table and when I click on a row I show another table with a bit more details about the parent row. Here is how I approached it.

I created a class that extends Panel to place my tables on. I then used a VerticalLayout to hold the tables. I created the master table and had it immediate=true so it displayed the data right away. I also created the detail table in this class but turned immediate=false and visibility=false.

I then created a new class that is the Table Listener which implements Property.ValueChangeListener. I used a new class for this for 2 reasons; 1) I’m writing all my code in Groovy and groovy doesn’t like inner classes and 2) I just think it’s a better pattern to go this route. This class looks like this:


class GenTypeAttributeTableListener implements Property.ValueChangeListener {

  def attTable
  def valueTable

  public GenTypeAttributeTableListener(attTable, valueTable) {
    this.attTable = attTable
    this.valueTable = valueTable
  }

  void valueChange(ValueChangeEvent valueChangeEvent) {
    if (attTable.value) {
      def container = new BeanItemContainer<GenAttributeValue>(GenAttributeValue.class)
      def values = GenAttributeValue.findAllByGenAttribute(attTable.value)
      values.each {
        container.addBean it
      }
      valueTable.containerDataSource = container
      valueTable.visibleColumns = ["value", "sequenceNo"]

      valueTable.visible = true
    }
  }
}

Note that I have to pass both the master and detail tables into this listener constructor. This works great. But I’m wondering if this is really how I should be dealing with this scenario. Any advice is much appreciated.

Gregg

2

Thought I’d bump this in case it got overlooked. Eagerly awaiting replies.

Thanks

Gregg

3

This works fine for smaller data sets. For larger datasets you might want to consider using containers that load data lazily (and does not store all beans in memory).

4

Right, thanks Joonas. Aside from the datasets, however, is this appropriate design for managing the detail table? Is it appropriate to use the Listener in this fasion? Is there a more “Vaadin” way or something more appropriate?