This class is used for dealing the special xml format files:
<config>
<node1 name="">
<node2 name=""/>
</node1>
</config>
which node/element has only an attribute and the name of the attribute is
unique, such as "name","value"
You can read a node/element's attribute value, by get***value(path,
defaultValue),example:
getStringValue("config/node1", "");
The path = "config" + "/" + "node1".
Remark, after you new an object of this class, you should remember calling
the obj.loadXML() to start reading the xml file.