code: @VisibleForTesting
      @Nullable
      protected LineSymbolizer createLineSymbolizer(final PJsonObject styleJson) {
          final Stroke stroke = createStroke(styleJson, true);
          if (stroke == null) {
              return null;
          } else {
              return this.styleBuilder.createLineSymbolizer(stroke);
          }
      }
docs: Add a line symbolizer definition to the rule.
  
  @param styleJson The old style.