JSP Custom Tags: Bringing Components to the Web - Creating a Custom Tag continued

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Creating the TLD File

As mentioned before, a TLD file is an XML document that describes the library. The TLD  contains the information about the library as a whole, as well as about individual tags. The information about the complete library is provided with the XML tags in the following table.

XML Tag	Definition
<taglib>	The tag library itself. The following tags are the child nodes of this tag.
<tlibversion>	The tag library's version.
<jspversion>	The JSP  version that is required to make the tag work.
<shortname>	A simple default name with a mnemonic value. For example, <shortname>  may be used as the preferred prefix value in taglib directives and/or to create prefixes for IDs.
<uri>	An optional URI that uniquely identifies the tag library.
<info>	Descriptive information about the tag library.

           

 The tag specific info is described using the following XML tags: 

• <tag>: The data about the tag itself is described by the siblings of this tag, which are detailed below. 
  
• <name>: The name by which the tag would be accessed is given by this XML element. 
  
• <tagclass>: The name of the class that handles the tag, a.k.a  the tag handler's name. the value of this element must be fully qualified Java name.
  
• <bodycontent>: The value of this tag determines whether the content of the tag has to be considered or not. There can be three values: empty to indicate that the tag has no body, and that an error will be produced if it has one; tagdependent, to indicate that the body is only processed by tag; and JSP, which states that the JSP container should evaluate any body of the tag.
  
• <attribute>: The info about the tag's attribute. The following child nodes provides various information:
  
  • <name>: Name of the attribute.
    
  • <required>: Declares whether the attribute is mandatory or not.
    
  • <rtexpvalue>: Lets the <attribute> tag use a runtime expression value if the value of this element is set to "true" or "yes."

That covers the contents of the TLD file. In the next section I will be creating a tag. In it the above tags will be used to create the mapping. So here comes the (nearly) real world example.

Next: Custom Tags in the Real World >>
 

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