Declaring Tag Variables in Tag Files

Tag attributes are used to customize tag behavior much as parameters are used to customize the behavior of object methods. In fact, using tag attributes and EL variables, it is possible to emulate various types of parameters: IN, OUT, and nested.
To emulate IN parameters, use tag attributes. A tag attribute is communicated between the calling page and the tag file when the tag is invoked. No further communication occurs between the calling page and the tag file.

AttributeDescription
description(optional) An optional description of this variable. Defaults to no description.
name-given | name-from-attributeDefines an EL variable to be used in the page invoking this tag. Either name-given or name-from-attribute must be specified. If name-given is specified, the value is the name of the variable. If name-from-attribute is specified, the value is the name of an attribute whose (translation-time) value at the start of the tag invocation will give the name of the variable.
Translation errors arise in the following circumstances: 1. Specifying neither name-given nor name-from-attribute or both.
2. If two variable directives have the same name-given.
3. If the value of a name-given attribute of a variable directive is equal to the value of a name attribute of an attribute directive or the value of a dynamic-attributes attribute of a tag directive.
aliasDefines a variable, local to the tag file, to hold the value of the EL variable. The container will synchronize this value with the variable whose name is given in name-from-attribute.
Required when name-from-attribute is specified. A translation error results if used without name-from-attribute.
A translation error results if the value of alias is the same as the value of a name attribute of an attribute directive or the name-given attribute of a variable directive.
variable-class(optional) The name of the class of the variable. The default is java.lang.String.
declare(optional) Whether or not the variable is declared. True is the default.
scope(optional) The scope of the variable. Can be either AT_BEGIN, AT_END, or NESTED. Defaults to NESTED.

To emulate OUT or nested parameters, use EL variables. The variable is not initialized by the calling page but instead is set by the tag file. Each type of parameter is synchronized with the calling page at various points according to the scope of the variable. See Variable Synchronization for details.

References By: oracle « Privious Post » « Next Post » share on :        :  

Love to hear your Views / Guidance / Recommendations on this Post…

Explore the Technology World

Computer Programming Terminologies Computer Programming Terminology is a general word for the group of specialized words or meanings relating to Computer Programming, and also the study of such t ...Read MoreNew features in JDK 12 with IntelliJ IDEADeveloped by JetBrains (formerly known as IntelliJ) ,IntelliJ IDEA is a Java integrated development environment (IDE) for developing computer software. It is av ...Read MoreGoogle Pay API Implementation Demo for AndroidIn this youtube Channel by Android Developers ,Learn how to implement the Google Pay API for Android with just a few lines of code and how it works with your ex ...Read MoreUnit Testing in .NET Core and Azure Devops pipelineUnit testing is a software testing method by which individual units of source code, usage procedures,sets of one or more computer program modules together with ...Read MoreThe mind behind Linux & GIT : Linus TorvaldsLinus Torvalds transformed technology twice — first with the Linux kernel, which helps power the Internet, and again with Git, the source code management ...Read MoreTensorflow and deep learningWith Tensorflow ,deep machine learning transitions from an area of research into mainstream software engineering. ...Read MoreJava program to return all possible permutations from collection of distinct numbersexample of Java program to return all possible permutations from collection of distinct numbers ...Read MoreReal Time Analytics with Spring Application Development FrameworkSpring is the most popular application development framework for enterprise Java.Millions of developers use Spring to build simple, truly portable, fast and fle ...Read MorePath Setting in Java When an application is launched from command prompt Windows OS searches for the executable program in the current working directory. The prompt throws an error ...Read MoreFacebook | whatsapp|Github | Twitter | LinkedIn | Youtube| reddit About | Cookies-Policy | Disclaimer | Site Map | Contact

Call / Visit for New Batch

Services

Why Join Us

  • ➯ Free Demo Classes
  • ➯ No Registration Fee
  • ➯ Interview Questions
  • ➯ Study Materials
  • ➯ Softwares
  • ➯ Aptitude & Reasoning
  • ➯ Placement Assitance

Address

  • MyJava Training Institute ,
  • Plot No.243 , shop No 14 ,
  • Secnd Floor , Zone-II ,
  • M.P.Nagar , Bhopal,
  • Madhya Pradesh ( 462011 )
  • ☎  08871209400 , 7987028543
  • 🌐 www.myjava.in
FacebookGoogle +TwitterYouTube

MyJava - java Training Institute