struts interview questions

Ques: 76 Describe the <tiles:useAttribute/> and <tiles:importAttribute/> tags in Tiles tag library in Struts framewrok?

Ans: The <tiles:useAttribute/> tag is used to retrieve a Tiles object from the Tiles context and expose that object as a scriptlet variable. The <tiles:useAttribute/> tag has no body and supports five attribute:

name, id, className, scope, ignore.

The <tile:importAttribute/> tag is ues to import a Tiles object from the Tiles context into a JSP scriptlet variable, which is stored in the named scope. If the name and scope attributes are not included are not included in the tag instance, then all Tile objects stored in the Tiles context are imported and placed in page scope. The < tiles:importAttribute/> tag has no body and supports three attributes:

name, scope, ignore.

Ques: 77 Which tag can be used to initialize the Tiles definition factory in Struts framework?

Ans: The <tiles:initComponentDefintions/> tag is used to initialize the Tiles definition factory. This tag is evaluated only once or not at all if the factory has already been initialized by other means. The <tiles:initComponentDefinition/> has no body and supports two attributes:

  * file : The file containing your Tile definitions.(Required)

  * classname : The fully qualified classname of the definition factory being initialized. This class, if specified, must implement the org.apache.struts.tiles.DefinitionFactory.(Optional)

Ques: 78 What are the steps involved in installing the Logic tag library in your Struts application?

Ans: To use the Logic tag library in web application, You must complete the following steps:

  * Copy the TLD file packaged with this tag library struts-logic.tld) to the webapps/MyAppName/WEB-INF directory.

  * Make sure that the struts.jar file is in the webapps/MyAppName/WEB-INF/lib directory.

  * Add the following <taglib> sub-element to the web.xml file of the Web application:

  <taglib>

    <taglib-uri>/WEB-INF/struts-logic.tld</taglib-uri>

    <taglib-location>/WEB-INF/struts-logic.tld</taglib-location>

  </taglib>

You must add the following taglib directive to each JSP that will leverage the HTML tag library:

  <%@ taglib uri="/WEB-INF/struts-logic.tld" prefix="logic" %>

Ques: 79 What is the use of <logic:empty/> and <logic:notEmpty/> tag defined by Logic tag library in Struts framework?

Ans: The <logic:empty/> tag evaluates its body if either the scripting variable identified by the name attribute or a property of the named scripting variable is equal to null or an empty string. The <logic:empty/> tag has a body type of JSP and supports three attributes:

  * name : Identifies the scripting variable being tested.

  * property : Identifies the data member of the scripting variable ot be tested.(optional)

  * scope : Defines the scope of the bean specified by the name attribute.

The <logic:notEmpty/> tag evaluates its body if either the scripting variable or property of the named scripting variable is not equal to null or an empty string. The <logic:empty/> tag has a body type of JSP and supports three attributes:

  * name : Specifies a scripting variable to be used as the variable being tested.(Required)

  * property : Specifies the data member of the scripting variable to be tested.(optional)

  * scope : Defines the scope of the bean specified by the name attribute.

Ques: 80 What is the use of <logic:equal/> and <logic:notEqual/> tag defined by Logic tag library in Struts framework?

Ans: The <logic:equal/> tag evaluates its body if the variable specified by any one of the attributes cookie, header, name, property, parameter equals the constant value specified by the value attribute. The <logic:equal/> tag has a body of JSP and supports seven attributes:

value, cookie, header, name, property, parameter, scope.

Example:

<logic:equal name="user"

  property="age"

  value="<%= requiredAge %>">

  You are exactly at the right age.

</logic:equal>

The <logic:notEqual/> tag evaluates its body if the variable specified by any one of the attributes cookie, header, name, property, parameter is not equal to the constant value specified by the value attribute. The <logic:equal/> tag has a body of JSP and supports seven attributes:

value, cookie, header, name, property, parameter, scope.

Example:

<logic:notEqual name="user"

  property="age"

  value="<%= requiredAge %>">

  You are not at the right age.

</logic:equal>