code: public void buildConstantSummaries(XMLNode node, Content contentTree) {
          PackageDoc[] packages = configuration.packages;
          printedPackageHeaders = new HashSet<String>();
          Content summariesTree = writer.getConstantSummaries();
          for (int i = 0; i < packages.length; i++) {
              if (hasConstantField(packages[i])) {
                  currentPackage = packages[i];
                  //Build the documentation for the current package.
                  buildChildren(node, summariesTree);
              }
          }
          contentTree.addContent(summariesTree);
      }
docs: Build the summary for each documented package.
  
  @param node the XML element that specifies which components to document
  @param contentTree the tree to which the summaries will be added