Chapter 6 – Custom Actions

Publisher Summary This chapter is designed to illustrate custom tags. Custom tags permit JavaServer Pages (JSP) developers to simplify complex tasks, and they form the basis for how the JSTL is actually implemented. The ability to create custom actions has been around since version 1.2 of the JSP specification, and it provides great power to JSP developers. Custom actions introduce new language constructs, which can introduce dependencies that complicate application development, deployment, and maintenance. This concern was one of the primary drivers behind the development of the JSTL, which should always be used in lieu of custom actions wherever possible. This chapter provides an overview of custom actions and also introduces and demonstrates the different methods that can be used to create them. Custom actions can provide powerful functionality in a flexible mechanism. The actions introduced in the JSTL provide useful models for developing one's own custom actions. Custom actions can be empty or they can have a body. They can also take attributes and cooperate, either implicitly when nested or explicitly through scoped attributes.