* Utility class that provides common access to the <a href="www.ognl.org">Ognl</a> APIs for
* setting and getting properties from objects (usually Actions).
+ * <!-- START SNIPPET: javadoc1 -->
+ * Ognl by default uses expression parsing for expression evaluation. However starting from Ognl 2.7.1, Ognl is capable
+ * of doing expression compilation using <a href="http://www.csg.is.titech.ac.jp/~chiba/javassist">Javassist</a> for
+ * expression evaluation. WebWork 2.2.7 / XWork1.2.4 and above support this functionality, however it is turn off by default to
+ * preserved backwards compatibilities. To turn it on, we need to use the following Doctype :-
+ * <!-- END SNIPPET: javadoc1 -->
+ * <!-- START SNIPPET: dtd -->
+ * <!DOCTYPE xwork PUBLIC
+ * "-//OpenSymphony Group//XWork 1.1.2//EN"
+ * "http://www.opensymphony.com/xwork/xwork-1.1.2.dtd">
+ * <!-- END SNIPPET: dtd -->
+ * <!-- START SNIPPET: javadoc2 -->
+ * And also declare a parameter "useOgnlEnhancement" with value "true" in xwork.xml as follows.
+ * <!-- END SNIPPET: javadoc2 -->
+ * <!-- START SNIPPET: sample -->
+ * <!-- enable OGNL expression compilation feature -->
+ * <parameter name="useOgnlEnhancement" value="true" />
+ * <!-- END SNIPPET: sample -->
+ * <!-- START SNIPPET: javadoc3 -->
+ * NOTE: Do take note that parameters declared in xwork.xml or its included files will override where the latter takes
+ * precedence. For example if we have a parameter declared in xwork.xml and one in xwork-include1.xml which is included
+ * through xwork.xml, the parameter declared in xwork-include1.xml will override the one declared in xwork.xml. In
+ * other words the parameter declared in xwork-include1.xml takes precedence.
+ * <!-- END SNIPPET: javadoc3 -->