Vaadin and DataModel. How can i get the value stored by a Property DataModel implementation used by a Label Field ??? Vaadin

Question

Hi,

It is just a simple TEST application

import br.com.elf.ui.IndexApplication;

public class IndexApplication extends Application {

    public void init() {
        setMainWindow(getStartUpWindow());
    }

    private Window getStartUpWindow() {
        Window mainWindow = new Window();

        mainWindow.addComponent(
            new Label(new Property() {
                public Object getValue() {
                    return "DataModel Example";
                }

                public void setValue(Object value) throws ReadOnlyException, ConversionException {
                    throw new ReadOnlyException();
                }

                public Class<?> getType() {
                    return String.class;
                }

                public boolean isReadOnly() {
                    return true;
                }

                public void setReadOnly(boolean readyOnly) {
                    // Empty body
                }
            ));
        }

        return mainWindow;
    }

}

Notice i have i plain Label field. I know i can just call

mainWindow.addComponent(new Label("DataModel Example"));

instead. But in order to see how Property DataModel works behind the scenes, i have added a Property implementation. But instead of seeing in output

DataModel Example

I get

br.com.elf.ui.IndexApplication$1@63a721

Why ???

And what the real purpose of Object getType() method defined in Property interface ??? If HTML shows its output in plain String, so i think there is no reason to implement a Object getType(), do not ???

regards,

Answer 1

I found out why,

The method used to show its value in human-redable textual format is toString. As said in Property API

returns the value of the Property in human readable textual format.

As shown bellow

mainWindow.addComponent(new Label(new Property() {
        public Object getValue() {
            return "Wellcome to Vaadin!";
        }

        public void setValue(Object newValue) throws ReadOnlyException, ConversionException {
            throw new ReadOnlyException();
        }

        public Class<?> getType() {
            return String.class;
        }

        public boolean isReadOnly() {
            return true;
        }

        public void setReadOnly(boolean newStatus) {
            throw new UnsupportedOperationException();
        }

        @Override
        public String toString() {
            return (String) getValue();
        }
    }));

And getType method tells you the type stored by this Property, nothing else. It can be anything, even a Account class, for instance. The value shown by the Component itself is always derived from toString method.

regards,