else if (name.equals (Literals.ISDEFINED))
result = new IsDefinedExpression (e, getRequestedResourcePool());
else if (name.equals (Literals.NOT_ISDEFINED))
result = new NotIsDefinedExpression (e, getRequestedResourcePool());
else
throw new InvalidQueryException
("operator <" + NamespaceCache.DEFAULT_URI + ":" + name + "> is an unprocessable entity");