To use this class, you configure the name of the bean you wish to invoke and
what method on that bean should be invoked with what arguments, typically
using flow request context attributes.
Example configuration and usage:
MethodSignature method = new MethodSignature("myMethod");
BeanFactory factory = ...
BeanFactoryInvokingAction action = new BeanFactoryBeanInvokingAction(method, "myBean", factory);
MockRequestContext context = new MockRequestContext();