Change Uniform var of Shaders on vtk 8.2

Hi groups,

I already know in vtk-9.1, we can easily get uniforms by vtkShaderProperty.
But with vtkOpenglMapper, we only have addreplacement and reset function.
Does it means we have to save the shader code in memory, and do [reset–str replace–add] loop?
I noticed that there is a class named vtkOpenGLUniforms, but I can’t find any documents of it.
Will it works for my problems?

Thank you!