The Java EE 5 Tutorial

3.Getting Started with Web Applications

7.JavaServer Pages Standard Tag Library

Dynamic Attribute or Deferred Expression

Encapsulating Reusable Content Using Tag Files

Declaring Tag Attributes in Tag Files

Declaring Tag Variables in Tag Files

Evaluating Fragments Passed to Tag Files

Simple and Fragment Attribute and Variable Example

Top-Level Tag Library Descriptor Elements

Declaring Tag Attributes for Tag Handlers

Declaring Tag Variables for Tag Handlers

Including Tag Handlers in Web Applications

How Is a Simple Tag Handler Invoked?

Tag Handlers for Tags with Attributes

Defining Attributes in a Tag Handler

Setting Deferred Value Attributes and Deferred Method Attributes

Tag Handler Does Not Manipulate the Body

Tag Handlers for Tags That Define Variables

11.Using JavaServer Faces Technology in JSP Pages

12.Developing with JavaServer Faces Technology

16.Building Web Services with JAX-WS

17.Binding between XML Schema and Java Classes

19.SOAP with Attachments API for Java

21.Getting Started with Enterprise Beans

24.Introduction to the Java Persistence API

27.The Java Persistence Query Language

28.Introduction to Security in the Java EE Platform

32.Java EE Examples Using the JMS API

custom tags, which are extensions to the JSP language. Some examples of tasks that can be performed by custom tags include operating on implicit objects, processing forms, accessing databases and other enterprise services such as email and directories, and implementing flow control. Custom tags increase productivity because they can be reused in more than one application.

tag library, which defines a set of related custom tags and contains the objects that implement the tags. The object that implements a custom tag is called atag handler. JSP technology defines two types of tag handlers: simple and classic.Simpletag handlers can be used only for tags that do not use scripting elements in attribute values or the tag body.Classictag handlers must be used if scripting elements are required. Simple tag handlers are covered in this chapter, and classic tag handlers are discussed inChapter9, Scripting in JSP Pages.

tag fileis a source file containing a reusable fragment of JSP code that is translated into a simple tag handler by the web container. Tag files can be used to develop custom tags that are presentation-centric or that can take advantage of existing tag libraries, or by page authors who do not know Java. When the flexibility of the Java programming language is needed to define the tag, JSP technology provides a simple API for developing a tag handler in the Java programming language.

This chapter assumes that you are familiar with the material inChapter5, JavaServer Pages Technology, especially the sectionUsing Custom Tags. For more information about tag libraries and for pointers to some freely available libraries, see