2. Using the Tutorial Examples
3. Getting Started with Web Applications
5. JavaServer Pages Technology
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
Programming Simple 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 Handlers for Tags with Bodies
Tag Handler Does Not Manipulate the Body
Tag Handlers for Tags That Define Variables
10. JavaServer Faces Technology
11. Using JavaServer Faces Technology in JSP Pages
12. Developing with JavaServer Faces Technology
13. Creating Custom UI Components
14. Configuring JavaServer Faces Applications
15. Internationalizing and Localizing Web Applications
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
23. A Message-Driven Bean Example
24. Introduction to the Java Persistence API
25. Persistence in the Web Tier
26. Persistence in the EJB Tier
27. The Java Persistence Query Language
28. Introduction to Security in the Java EE Platform
29. Securing Java EE Applications
31. The Java Message Service API
32. Java EE Examples Using the JMS API
36. The Coffee Break Application
Chapter 8
Custom Tags in JSP Pages
The standard JSP tags simplify JSP page development and maintenance. JSP technology alsoprovides a mechanism for encapsulating other types of dynamic functionality incustom tags, whichare extensions to the JSP language. Some examples of tasks that can beperformed by custom tags include operating on implicit objects, processing forms, accessing databases andother enterprise services such as email and directories, and implementing flow control. Customtags increase productivity because they can be reused in more than one application.
Custom tags are distributed in atag library, which defines a set of related customtags and contains the objects that implement the tags. The object that implementsa custom tag is called atag handler. JSP technology defines two types oftag handlers: simple and classic.Simple tag handlers can be used onlyfor tags that do not use scripting elements in attribute values or thetag body.Classic tag handlers must be used if scripting elements are required.Simple tag handlers are covered in this chapter, and classic tag handlers arediscussed inChapter 9, Scripting in JSP Pages.
You can write simple tag handlers using the JSP language or using theJava language. Atag file is a source file containing a reusable fragmentof JSP code that is translated into a simple tag handler by theweb container. Tag files can be used to develop custom tags that arepresentation-centric or that can take advantage of existing tag libraries, or by pageauthors who do not know Java. When the flexibility of the Java programminglanguage is needed to define the tag, JSP technology provides a simple APIfor developing a tag handler in the Java programming language.
This chapter assumes that you are familiar with the material inChapter 5, JavaServer Pages Technology,especially the sectionUsing Custom Tags. For more information about tag libraries and for pointers tosome freely available libraries, seehttp://www.oracle.com/technetwork/java/index-jsp-135995.html.
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