EL expressions are one of the main driving forces for JavaServer Faces. Most dynamic characteristics of pages and widgets are governed by EL expressions. In JSF 1.x, there are some limitations for EL expressions that can at times be a little frustrating. One of the limitations is the fact that no custom functions or operators can be used in EL expressions. Quite some time ago, I wrote this article – http://technology.amis.nl/blog/622/how-to-call-methods-from-el-expressions-pre-jsp-20-trick-for-jsps-with-jstl – to demonstrate a trick for using a Map interface implementation to access custom functionality from EL expression after all.

However, things can even be better. Rather than jumping through the somewhat elaborate hoops of implementing the Map and consructing complex EL expressions, there are two other approaches. One is to create a custom EL Resolver can configure it in the faces-config.xml. Another is discussed in this article. It involves registering custom Java methods as eligible for use in EL expressions. And that really makes life a lot easier. It allows us to create EL expressions such as:

#{cel:concat (cel:upper( bean.property), cel:max(bean2.property, More >