This quote() method is not called. I am using xwork-2.0.1.jar and ognl-2.6.11.jar.
You don't have that method in your action. If you create it:
public String quote() {
and use normal OGNL method call syntax:
<s:property value="%{quote()}" />
then it will be called as desired.
For details information and syntax you can read OGNL Language Guide.