Jakarta Project: Input Tag library

Version: 1.0

Overview
Requirements
Configuration
Tag Summary
Tag Reference
Examples
Javadocs
Revision History

Overview

The "input" tag extension library lets you present HTML <form> elements that are tied to the ServletRequest that caused the current JSP page to run. That is, using this library, you can easily prepopulate form elements with prior values that the user has chosen -- or with default values for the first time a user hits a web page. This is useful when you need to present the same page to the user several times (e.g., for server-side validation).

You can also automatically build up <select> boxes, making it easier to build data-driven forms. And even if you don't present the same page multiple times, you may want form elements that have default values; this library lets you do that without writing excessive logic.

What is the "Input" tag library? Read more.

Requirements

This custom tag library requires no software other than a servlet container that supports the JavaServer Pages Specification, version 1.1 or higher. Plus any requirements for additional API packages.

Configuration

Follow these steps to configure your web application with this tag library:

Copy the tag library descriptor file to the /WEB-INF subdirectory of your web application.
Copy the tag library JAR file to the /WEB-INF/lib subdirectory of your web application.

Add a <taglib> element to your web application deployment descriptor in /WEB-INF/web.xml like this:

<taglib>
  <taglib-uri>http://jakarta.apache.org/taglibs/input-1.0</taglib-uri>
  <taglib-location>/WEB-INF/input.tld</taglib-location>
</taglib>

To use the tags from this library in your JSP pages, add the following directive at the top of each page:

<%@ taglib uri="http://jakarta.apache.org/taglibs/input-1.0" prefix="input" %>

where "input" is the tag name prefix you wish to use for tags from this library. You can change this value to any prefix you like.

Tag Summary

Input Tags

text	Displays a one-line text-entry box
textarea	Displays a multiline textarea
select	Displays a select list
radio	Displays a radio button
checkbox	Displays a checkbox

Tag Reference

text				Availability: 1.0
Displays a one-line text-entry box. See Usage page.
Tag Body	empty
Restrictions	None
Attributes	Name	Required	Runtime Expression Evaluation	Availability
	name	Yes	Yes	1.0
	text box name
	default	No	Yes	1.0
	text box default value
	attributes	No	Yes	1.0
	extra text box attributes
Variables	None
Examples	None

textarea				Availability: 1.0
Displays a one-line text-entry box. See Usage page.
Tag Body	empty
Restrictions	None
Attributes	Name	Required	Runtime Expression Evaluation	Availability
	name	Yes	Yes	1.0
	textarea name
	default	No	Yes	1.0
	textarea default value
	attributes	No	Yes	1.0
	extra textarea attributes
Variables	None
Examples	None

select				Availability: 1.0
Displays a select list. See Usage page.
Tag Body	empty
Restrictions	None
Attributes	Name	Required	Runtime Expression Evaluation	Availability
	name	Yes	Yes	1.0
	select name
	default	No	Yes	1.0
	select default value
	attributes	No	Yes	1.0
	extra select attributes
	options	Yes	Yes	1.0
	options list for select
Variables	None
Examples	None

radio				Availability: 1.0
Displays a radio button. See Usage page.
Tag Body	empty
Restrictions	None
Attributes	Name	Required	Runtime Expression Evaluation	Availability
	name	Yes	Yes	1.0
	radio button name
	default	No	Yes	1.0
	radio button default value.
	value	Yes	Yes	1.0
	value can be empty, but it must be present
	attributes	No	Yes	1.0
	extra radio button attributes
Variables	None
Examples	None

checkbox				Availability: 1.0
Displays a checkbox. See Usage page.
Tag Body	empty
Restrictions	None
Attributes	Name	Required	Runtime Expression Evaluation	Availability
	name	Yes	Yes	1.0
	checkbox name
	default	No	Yes	1.0
	The two "defaults" for checkbox are concatenated together to form an array of size (defaults.length + 1), or 1 if defaults.length is null or isn't present
	defaults	No	Yes	1.0
	The two "defaults" for checkbox are concatenated together to form an array of size (defaults.length + 1), or 1 if defaults.length is null or isn't present
	value	Yes	Yes	1.0
	value can be explicitly empty, or it can be absent, in which case it defaults to "on"
	attributes	No	Yes	1.0
	extra checkbox attributes
Variables	None
Examples	None

Examples

See the example application input-examples.war for examples of the usage of the tags from this custom tag library.

Java Docs

Java programmers can view the java class documentation for this tag library as javadocs.

Revision History

Review the complete revision history of this tag library.