Ketan's Musings

viewer = new DoubleListViewer(shell, SWT.NONE);

viewer.setSourceLabel(SOURCE_LIST_LABEL);
viewer.setDestinationLabel(DESTINATION_LIST_LABEL);

viewer.setLabelProvider(new LabelProvider());
viewer.setContentProvider(new ContentProvider());

viewer.setUseHashlookup(true);

// filter the input so that part of it is shown in the source list.
viewer.setSourceFilter(new SourceListFilter());

// filter the input so that part of it is shown in the destination list.
viewer.setDestinationFilter(new DestinationListFilter());

// helps in reordering the destination list (Up/Down buttons)
viewer.setReorderingFilter(new ListReorderFilter());

// moves objects to and fro between the two lists.
viewer.setAddRemoveFilter(new ListAddRemoveFilter());

// finally the model for the view
viewer.setInput(getFullList());

public interface DoubleListFilter {
    public abstract Object filter(Object toTest);
}

public abstract class AbstractReorderFilter {

    public abstract Object moveUp(Object input, Object toMove, int numPlaces) ;

    public Object moveUp(Object input, Object toMove){
        return moveUp(input, toMove, 1);
     }

    public abstract Object moveDown (Object input, Object toMove, int numPlaces);

    public Object moveDown(Object input, Object toMove){
        return moveDown(input, toMove, 1);
    }
}

public abstract class AbstractAddRemoveFilter {

    public abstract void add(Object source, Object toAdd);

    public abstract void remove(Object source, Object toRemove);

    public void move(Object source, Object dest, Object toMove) {
        add(dest, toMove);
        remove(source, toMove);
    }
}