if(grammar.getTargetNamespace() == null) fGrammarRegistry.put(EMPTY_STRING, grammar);
if (grammar.getTargetNamespace() == null) fNoNSGrammar = grammar;
    public void putGrammar(SchemaGrammar grammar) {        if(grammar.getTargetNamespace() == null)            fGrammarRegistry.put(EMPTY_STRING, grammar);        else            fGrammarRegistry.put(grammar.getTargetNamespace(), grammar);    }