Struts Tutorials:
Struts2 Tag CheckBoxList
, Checkbox, Iterator, IF
Struts2 Tag Library Example
Struts2 Tiles Example
Struts2 Tiles I18N Example
Struts2 Questions
Struts Tiles I18N Example
Struts Eclipse MVC
Struts2 Tags
Struts2 Example and Tutorial
Struts MVC
Struts2 Validation



Hibernate Tutorials:
Hibernate Case Study
Class Hierarchy Persist Example
Using Hibernate Interceptor
Hibernate Questions with Answer
Hibernate Many-to-Many Mapping Example
Hibernate one-to-many Mapping Example
Hibernate and ORM tools
Spring Hibernate Example
Hibernate SessionFactory Example
Hibernate Mapping Class Hierarchy
Hibernate Questions
Hibernate SessionFactory Questions

Spring Hibernate Example:
Spring Hibernate Case Study

Written By : ISHTEK
Title :
Struts2

Description :
Tags such as IF Iterator Tags
More...

Written By : guddu
Title :
Struts Eclipse MVC

Description :
Step by step demonstration
More...

Written By : Girish
Title :
Struts Tiles I18N Example

Description :
Code with Sample Action
More...

Written By : ISHTEK
Title :
Struts2 questions

Description :
open for discussion
More...

Written By : ISHTEK
Title :
Struts2 Tiles Example

Description :
with Code and article
More...

Written By : ISHTEK
Title :
Struts2 Tiles I18N Example

Description :
with code explained article
More...

Written By : Amit
Title :
Struts2 Tag Library Example

Description :
Tutorial
More...

Tags/Keywords : Struts, Struts2 Tutorial, Struts 2 Example, Struts2
Author : ISHTEK
Date (Year/Month/Date): 2009-09-13
Struts2.1.6- Result type "chain" discussed with an example

Please be informed that NONE of the design/code from this
page is claiming to be some sort of best practices and we DO NOT expect
any of our visitor/reader of this page to assume this as some sort of
best practice for any context and should not be using this 
as it is without appropriate evaluation to their, so to say, 
specific programming context.

This page intends only to provide bit and piece of known ways  for
doing some sort of example and may not be fit for any other purpose.


Struts version 2.1.6  - Result Type as the Action chain with an example
I have sometimes felt that Action chaining is required if the business
requirement is to perform some generic action before forwarding request
to another page navigational action, like for example,
if certain service that is very generic in nature and should not be
bundled with all the View/UI/Page navigation Action class files, 
instead if thie service has to be a re-usable component and associated
action should be called first and then the Page forward should happen.
Then in this case, Struts Action chain Result type definition can be
very useful.



Advertisement : 



In this example, I shall try to show a very simple functionality,
that you might have already read in some other example in this site.

Like for example, a screen having two fields testHeader and testFooter.
Both these text fields values are set by user and on submit for the form
, a Action (in this case ExampleInitialAction) will be called.

But surprisingly this Action class is not having these two fields/variables
in it, but it just return the result name (that is "preview"), but in 
struts.xml configuration file, this result is of type "chain", and
some of the param such as "namespace" and "actionName" takes the processing
to another action that is "xslt-view" with namespace as "/sample-xslt".
And the action class file name is "ExampleXSLTAction".
this action receives values from those text fields "testHeader" and 
"testFooter" and returns either "preview" or "input" string value.
Hence the output screen is shown with the help of appropriate XSLT file.

Let us see struts.xml file as follows:
struts.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
    <package name="initial" namespace="/sample"
                 extends="struts-default">
        <action name="test" class="sample.ExampleInitialAction" 
	                       method="preview">
        <result name="preview" type="chain">
	      <param name="namespace">/sample-xslt</param>
		  <param name="actionName">xslt-view</param>
		</result>
        </action>
    </package>
    <package name="xslt-example" namespace="/sample-xslt"
                 extends="struts-default">
        <action name="xslt-view" class="sample.ExampleXSLTAction" 
	                       method="preview">
                <result name="preview" type="xslt">
		  <param name="stylesheetLocation">
		    /sources/test.xslt
		  </param>
		</result>
                <result name="input">/index.jsp</result>
        </action>
    </package>
</struts>



As you can go through the above struts.xml file, we have here two Action
class files, as follows:

sample.ExampleInitialAction.java

package sample;

public class ExampleInitialAction
{
    public String preview() throws Exception{
        return "preview";
    }
}




And

sample.ExampleXSLTAction.java

package sample;

public class ExampleXSLTAction {
	private String testHeader;
	private String testFooter;
	public void setTestHeader(String arg) {
		testHeader = arg;
	}
	public String getTestHeader(){
		return testHeader;
	}
	public void setTestFooter(String arg) {
		testFooter = arg;
	}
	public String getTestFooter(){
		return testFooter;
	}
    public String preview() throws Exception {
		if((testHeader != null && testHeader.length() >0) &&
			(testFooter != null && testFooter.length() <0))
            return "preview";
		else
            return "input";
	}
}



We have a XSLT file as follows: 

/sources/test.xslt

<?xml version="1.0"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
                version="1.0">
<xsl:output method="html"/>
<xsl:template match="result">
<html>
<body>
      <h4><xsl:value-of select="testHeader"/></h4>
      <br/>
      <xsl:value-of select="testFooter"/> 
</body>
</html>
</xsl:template>
</xsl:stylesheet>



and the index.jsp is very straight forward:
index.jsp

<%@ taglib uri="/struts-tags" prefix="struts2"%>
<html>
<head>
</head>
<body>
<struts2:form method="post" action="test" namespace="/sample">
<table>
<tr><td><struts2:textfield key="testHeader" label="Enter Header :"/>
    </td></tr>
<tr><td><struts2:textfield key="testFooter" label="Enter Footer :"/>
    </td></tr>
<tr><td colspan="2"><struts2:submit value="Register"/></td></tr>
</table>
</struts2:form>
</body>
</html>




Web Application Descriptor file is same as any other example from this
site:
web.xml

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

<!DOCTYPE web-app
    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
    "http://java.sun.com/dtd/web-app_2_3.dtd">

<web-app>
  <filter>
  <filter-name>sample-filter</filter-name>
  <filter-class> 
    org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter
  </filter-class>
  </filter>
  <filter-mapping>
    <filter-name>sample-filter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
</web-app>





Advertisement : 



Anybody having any technical difficulties in setting up and 
running this example, please let me know by commenting in this
page using the form below.

Thanks for reading this.

Author of this article/writeup has expressed his/her willingness
to help or guide users with any technical difficulties he/she faces
while working with the example code environment setting up, running
and resolving any such exception raised during compile or at runtime.
You may ask for any technical doubt or seek technical help related to
this article by using following form to reach for technical help
from the Author for FREE.

This article's Author shall be reading your request and responding
within reasonable time (no resolution timeframe defined as such).

Copyright © 2008-2009, Interview-Questions-Tips-Forum, All Rights Reserved.