However, when a PropertyStates object is instantiated via the public PropertyStates(ByteQueue queue) constructor, the getState() function can generate ClassCastExceptions if it is not a BaseType.

In my case, I had a ClassCastException because this.state was a BinaryPV, which isn't a BaseType.

Changing

    public BaseType getState() {
        return (BaseType) state.getDatum();
    }

to this

    public Encodable getState() {
        return state.getDatum();
    }

resolves the problem. Or if getState returned this.state, that should probably work too.