j2ee: The Tag Library Descriptor [15/27]

In order for your tag library to be processed properly by the Servlet container, you must supply a configuration file known as a tag library descriptor. This basically servers the purpose of web.xml for a web application, it is information that the container uses to manage the libraries at runtime

http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd for JSP 2.0

http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd for JSP 1.2

http://java.sun.com/dtd/web-jsptaglibrary_1_1.dtd for JSP 1.1>

TLD structure:

• taglib - requires tlib-version, jsp-version, short-name, and tags. Optional are uri, description, validator (a TagLibraryValidator), and listeners.
  • tag - requires name and tag class, optional are body-content (JSP/empty, or tagdependent), variables entries (scripting variable names), attributes, tei (TagExtraInfo) classes, and description
    • attribute - requires name, required (whether it is required, false by default), rtexprvalue (whether it is a runtime JSP expression), type (must be fully qualified)

Examples:

<?xml version="1.0" encoding="UTF-8" ?>

<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
	http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
	version="2.0">


    <tlib-version>2.0</tlib-version>
    <jsp-version>2.0</jsp-version>
    <short-name>se452</short-name>
    <uri>/se452</uri>
    <display-name>se452-taglib</display-name>
    <small-icon></small-icon>
    <large-icon></large-icon>
    <description>
        A set of example tag libraries for SE452 at DePaul University
    </description>
    
    <tag>
        <name>date</name>
        <tag-class>se452.tags.DateTag</tag-class>
        <body-content>empty</body-content>
        <description>
        Prints the current time and date
        </description>
    </tag>
  
    <tag>
        <name>debug</name>
        <tag-class>se452.tags.DebugTag</tag-class>
        <body-content>JSP</body-content>
        <description>
        Includes the contents of the tag if debug request parameter
        is set to true
        </description>
    </tag>
    
    <tag>
        <name>select</name>
        <tag-class>se452.tags.SelectTag</tag-class>
        <body-content>empty</body-content>
        <description>
            Displays an html select with preselected options
        </description>
        <attribute>
            <name>name</name>
            <required>true</required>
            <rtexprvalue>true</rtexprvalue>
            <type>java.lang.String</type>
        </attribute>
        <attribute>
            <name>selected</name>
            <required>false</required>
            <rtexprvalue>true</rtexprvalue>
            <type>java.lang.String</type>
        </attribute>
        <attribute>
            <name>list</name>
            <required>true</required>
            <rtexprvalue>true</rtexprvalue>
            <type>java.lang.String</type>
        </attribute>
    </tag>
    
</taglib>