code: private Map<String,Namespace> buildByPrefixMap()
      {
          int len = mNamespaces.size();
          if (len == 0) {
              return Collections.emptyMap();
          }
  
          LinkedHashMap<String,Namespace> m = new LinkedHashMap<String,Namespace>(1 + len + (len>>1));
          for (int i = 0; i < len; ++i) {
              Namespace ns = mNamespaces.get(i);
              String prefix = ns.getPrefix();
              if (prefix == null) { // shouldn't happen but...
                  prefix = "";
              }
              m.put(prefix, ns);
          }
          return m;
      }
docs: /*
  ///////////////////////////////////////////
  Private methods:
  ///////////////////////////////////////////