thanks for your post.
Assuming that a weight is be a multiplier in [0.0,1.0], and the input values are only positive (including zero), you would just need to multiply the weight by the input value at the moment of setting the input value for the variable. For example,
variable.setValue(inputValue * weight);. If you want something a bit fancier, you can normalise the set of weights as it is done in in Proportional.java, thus requiring weights to be any positive value not necessarily in [0.0,1.0].