code: protected void addContextTerms(SparseDoubleVector meaning,
                                     Queue<String> words,
                                     int distance) {
          // Iterate through each of the context words.
          for (String term : words) {
              if (!term.equals(IteratorFactory.EMPTY_TOKEN)) {
                  // Ignore any features that have no valid dimension.
                  int dimension = basis.getDimension(term);
                  if (dimension == -1)
                      continue;
  
                  // Add the feature to the context vector and increase the
                  // distance from the focus word.
                  meaning.set(dimension, weighting.weight(distance, windowSize));
                  ++distance;
              }
          }
      }
docs: Adds a feature for each word in the context that has a valid dimension.
  Feature are scored based on the context word's distance from the focus
  word.