code: public AbstractBuilder getPackageSummaryBuilder(PackageDoc pkg, PackageDoc prevPkg,
              PackageDoc nextPkg) throws Exception {
          return PackageSummaryBuilder.getInstance(context, pkg,
              writerFactory.getPackageSummaryWriter(pkg, prevPkg, nextPkg));
      }
docs: Return the builder that builds the package summary.
  
  @param pkg the package being documented.
  @param prevPkg the previous package being documented.
  @param nextPkg the next package being documented.
  @return the builder that builds the constant summary.