How can I bind a property (e.g. an Enum) to a component property of a different type (e.g. an image for each Enum)?
I have inherited a project that uses JGoodies Binding to connect the domain model to th开发者_C百科e GUI. However, there are some inconsistencies that I have found which also cause some bugs.
In this concrete case, the GUI is represented by two radio buttons and a label. Depending on which button is selected, the label should display a certain image. The buttons are bound to different Enum values, like this:
AbstractValueModel enumSelectionModel = presentationModel.getModel("selection");
radioBtn1 = BasicComponentFactory.createRadioButton(enumSelectionModel,
Selection.selection1, "");
radioBtn2 = BasicComponentFactory.createRadioButton(enumSelectionModel,
Selection.selection2, "");
"selection"
is the bound property, and Selection
is the Enum, which means that when a different button is changed, the selection
property in my model is set to the corresponding Enum value.
My question is: How can I bind this property to the image displayed by the label?
From what I saw, JGoodies is excellent for binding things like strings to text fields, but in this case, there should also be a transformation, some logic which decides maps the enum property to the image.
Seems like I just had to take a closer look in the Binding API. An AbstractConverter
is exactly what I was looking for.
Bindings.bind((JComponent) pictureLabel, "icon", new EnumToIconConverter(enumSelectionModel));
The bind
method binds the pictureLabel's icon to the model described by the converter. The converter looks like this:
class EnumToIconConverter extends AbstractConverter {
EnumToIconConverter(ValueModel subject) {
super(subject);
}
@Override
public Object convertFromSubject(Object enum) {
return enum == Selection.selection1 ? image1 : image2;
}
@Override
public void setValue(Object obj) {
throw new UnsupportedOperationException("setValue makes no sense for this converter");
}
}
The convertFromSubject
method is where the transformation from Enum to image is done. I didn't implement setValue
because it makes no sense in this case. The image cannot change on its own, I only want updates to go one way - from the enum property to image.
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