Graphical Modeling Framework Runtime - Eclipse Modeling Project: A Domain-Specific Language Toolkit - page 498

Our LinkDecoratorProvider class appears next. It extends the
AbstractProvider and implements the IDecoratorProvider . In both the
provides() and createDecorators() methods, we use the getDecorator
TargetNode() static method on our LinkDecorator class, which is listed
below our provider code.

public class LinkDecoratorProvider extends AbstractProvider implements
IDecoratorProvider {

public static final String HYPERLINK_DECORATOR_ID = "hyperlink";

public boolean provides(IOperation operation) {
if ( false == operation instanceof CreateDecoratorsOperation) {
return false ;

}
IDecoratorTarget decoratorTarget =
((CreateDecoratorsOperation) operation).getDecoratorTarget();
return
LinkDecorator.getDecoratorTargetNode(decoratorTarget) != null ;

}

public void createDecorators(IDecoratorTarget decoratorTarget) {
Node node =
LinkDecorator.getDecoratorTargetNode(decoratorTarget);
if (node != null ) {
decoratorTarget.installDecorator(HYPERLINK_DECORATOR_ID, new
LinkDecorator(decoratorTarget));

}

}

}

public class LinkDecorator extends AbstractDecorator {

private static final Image LINK;

static {
URL url = FileLocator.find(Activator.getDefault().getBundle(),
new Path("images" + IPath.SEPARATOR + "link.gif"), null );
ImageDescriptor imgDesc = ImageDescriptor.createFromURL(url);
LINK = imgDesc.createImage();

}

public LinkDecorator(IDecoratorTarget decoratorTarget) {
super (decoratorTarget);

}

static public Node getDecoratorTargetNode(IDecoratorTarget
decoratorTarget) {
CustomStyle style = null ;
View node = (View) decoratorTarget.getAdapter(View. class );
if (node != null && node.eContainer() instanceof Diagram) {
style = (CustomStyle)
node.getStyle(StylePackage.eINSTANCE.getCustomStyle());
if (style != null ) {