This class provides the framework for a transfer to have different behaviours depending on the
strategy that is set.
For example:
A GeometryTextTransfer can encode the geometry as a GML string or a WKT string (as created by JTS WKTWriter).
The GeometryTextTransfer class subclasses AbstractStrategizedTransfer and only needs to provide the current
strategy and the set of possible strategies.
An DecoratorOverlayIcon consists of a main icon and several adornments.
Eclipse has many implementations of this class - all of them are internal.
This one is based on org.eclipse.ui.internal.decorators.DecoratorOverlayIcon
and has the advantage of having an equals and hashcode impemenation.