prefer(version).strict()
    }

    protected void selected(ComponentResolutionState state) {
        assert details.hasSelected()
        assert details.selected == state
    }

    protected void selected(String version) {
        assert details.hasSelected()
        assert details.selected.version == version
    }

    protected void resolutionFailedWith(String message) {

    void select(T candidate);

    void fail(Throwable error);

    @Nullable
    T getSelected();

    @Nullable
    Throwable getFailure();

    boolean hasFailure();

    boolean hasSelected();

    public Throwable getFailure() {
        return failure;
    }

    @Override
    public boolean hasFailure() {
        return failure != null;
    }

    @Override
    public boolean hasSelected() {
        return selected != null;
    }