code: private void doVerify(Parameter p) throws NamespaceSyntaxWarning {
          if (p.getValue() == null) {
              throw new InvalidArgument("parameter value is null");
          }
  
          Namespace ns = p.getNamespace();
  
          String resourceLocation = ns.getResourceLocation();
          if (resourceLocation == null) {
              throw new InvalidArgument("resourceLocation", resourceLocation);
          }
  
          // get opened namespace and lookup namespace parameter encoding
          JDBMNamespaceLookup il = openNamespaces.get(ns.getResourceLocation());
          if (il == null) {
              throw new IllegalStateException("namespace index is not open.");
          }
  
          String encoding = il.lookup(p.getValue());
          if (encoding == null) {
              throw new NamespaceSyntaxWarning(ns.getResourceLocation(),
                      ns.getPrefix(),
                      p.getValue());
          }
      }
docs: Do namespace value verification against a resource location. This
  implementation assumes the namespace has been open prior to execution.
  
  @param p {@link Parameter}, the parameter to verify namespace value for
  which cannot be null and must have a non-null namespace and value
  @throws NamespaceSyntaxWarning Thrown if parameter's {@link Namespace} is
  not null and it does not contain the parameter's value
  @throws InvalidArgument Thrown if <tt>p</tt> argument is null, its value
  is null, or if its namespace's resource location is null