Question

I am a new Vaadin user with JSF background.Currently i am trying to implement a simple
combobox using vaadin.What i want to do is,using a List as the itemlist of the combobox,showing Example.description field in the combobox,and when one of the items selected getting the Example object/Example.id as value.(as we do in JSF using itemLabel=example.description,itemValue=example/example.id properties of f:selectItems)

Answer 1

this is Ville from the Vaadin team. You can do this in quite many ways but in general you toggle your ComboBox behavior with the setItemCaptionMode() method.

However, pretty close to what you are trying to do is accomplished with the following example:

public class Example {

    private Integer id;
    private String description;

    public Example(Integer id, String description) {
        this.id = id;
        this.description = description;
    }

    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getDescription() {
        return description;
    }
    public void setDescription(String description) {
        this.description = description;
    }
}

@Override
public void init() {
    Window mainWindow = new Window("Combobox Application");

    List<Example> examples = new ArrayList<Example>();
    examples.add(new Example(new Integer(1), "First description"));
    examples.add(new Example(new Integer(2), "Second description"));
    examples.add(new Example(new Integer(3), "Third description"));
    BeanItemContainer<Example> objects = new BeanItemContainer(Example.class, examples);

    ComboBox combo = new ComboBox("Example", objects);
    combo.setItemCaptionPropertyId("description");

    mainWindow.addComponent(combo);
    setMainWindow(mainWindow);
}

Here the BeanItemContainer wraps your POJOs and uses reflection to access getters.

Cheers.