de></a>, 
a string representing 
the expression, and the expected type (<code>ValueExpression</code>) or signature 
(<code>MethodExpression</code>). 

The <code>ELContext</code> provides the context necessary to parse an expression.
Specifically, if the expression uses a Jakarta Expression Language function 
(for example <code>${fn:toUpperCase(customer.name)}</code>) or a Jakarta Expression Language 
variable, then <a href="../../javax/el/FunctionMapper.html" title="class in javax.el"><code>FunctionMapper</