code: @Override
      public void verify(Statement s) throws SymbolWarning, IndexingFailure,
              ResourceDownloadError {
  
          List<Parameter> parameters = s.getAllParameters();
          // first iteration to open all namespaces
          for (Parameter p : parameters) {
              if (p.getNamespace() == null
                      || p.getNamespace().getResourceLocation() == null) {
                  continue;
              }
              String resourceLocation = p.getNamespace().getResourceLocation();
  
              synchronized (resourceLocation) {
                  if (!isOpen(resourceLocation)) {
                      final String indexPath = doCompile(resourceLocation);
                      openNamespace(resourceLocation, indexPath);
                  }
              }
          }
  
          final List<NamespaceSyntaxWarning> exceptions =
                  new ArrayList<NamespaceSyntaxWarning>();
          for (Parameter p : s.getAllParameters()) {
              Namespace ns = p.getNamespace();
              if (ns == null) {
                  continue;
              }
  
              try {
                  doVerify(p);
              } catch (NamespaceSyntaxWarning w) {
                  exceptions.add(w);
              }
          }
  
          if (!exceptions.isEmpty()) {
              // TODO review name
              final String name = s.toString();
              final String fmt = INVALID_SYMBOLS;
              final String msg = format(fmt, exceptions.size());
              throw new SymbolWarning(name, msg, exceptions);
          }
      }
docs: {@inheritDoc}