class DummyObjectHolder implements ObjectHolder<CompilationState> {
        private CompilationState compilationState

        CompilationState get() {
            return compilationState
        }

        void set(CompilationState newValue) {
            this.compilationState = newValue
        }

        CompilationState update(ObjectHolder.UpdateAction<CompilationState> updateAction) {

    }

    public IncrementalCompileSourceProcessor files(CompilationState previousCompileState) {
        return new DefaultIncrementalCompileSourceProcessor(previousCompileState);
    }

    private class DefaultIncrementalCompileSourceProcessor implements IncrementalCompileSourceProcessor {
        private final CompilationState previous;