Struts 2 Validation, Struts2 Validation, Struts2 Expression, example

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In this writing I shall be showing an example to demonstrate how to
use validator for regex expressions using Struts 2 Framework and

I am going to use an already used example from this site, 
this example has a Bean as ExamplePOJOAction Java class file.

With validation for expression, I am going to use REGEX expression
along with the in-built validator from Struts 2 and supporting JAR files.

The ExamplePOJOAction has a private variable of type MyBean, and
named as "myBean", this is MyBean with a stdClass of type String.

So the field name that is to be used in the ..-validation.xml configuration
file is "myBean.stdClass".











In this example we have a validation XML file as <bean_name>-validation
XML file.

As the Bean Action name is "ExamplePOJOAction", so the validation 
XML configuration file is "ExamplePOJOAction-validation.xml", as shown below:

ExamplePOJOAction-validation.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE validators PUBLIC
        "-//OpenSymphony Group//XWork Validator 1.0.3//EN"
        "http://www.opensymphony.com/xwork/xwork-validator-1.0.3.dtd">
<validators>
  <field name="myBean.stdClass">
    <field-validator type="regex">
      <param name="expression">^[IVX]*$</param>
      <message>Please enter value using I, V, X only</message>      
    </field-validator>
  </field>
</validators>


Here in this example we are concerned about two Java class files,
one is the POJO Action class, and another one is a POJO Bean class.

In this example Action class is not really a POJO, as it extends
ActionSupport from xwork-2.1.2.jar.

One question came to my thought is why is this Action class extending
ActionSupport, answer is that without this Base ActionSupport class
our Action class won't be able to participate in validation that is
defined in validation XML file.

Here is the Action class for this example:
ExamplePOJOAction.java

package sample;
/**
 * This code is provided "AS IS" without any guaranty
 * Use of this code only for educational and learning
 * purpose only.
 * Author: Amit
 * Contact : http://www.techienjoy.com
 * Date: 16-Feb-2009
 */
import java.util.Map;
import com.opensymphony.xwork2.ActionSupport;

/**
 * This is the Action POJO class
 */
public class ExamplePOJOAction extends ActionSupport {
    private MyBean myBean;
    public String preview() throws Exception {
        return "preview";
    }
    public void setMyBean(MyBean argMyBean) {
        myBean = argMyBean;
    }
    public MyBean getMyBean() {
        return myBean;
    }
}



And the supporting value object MyBean is shown as below:
MyBean.java

package sample;
import java.util.List;
import java.util.ArrayList;

public class MyBean
{
    private String userName;
    private String roll;
    private String email;
    private String section;
    private String stdClass;
    private List subscriptionOptions;
    private List consentOptions;
    private boolean newsLetterOption;

    public String getUserName() {
        return this.userName;
    }
    public void setUserName(String argUserName) {
        userName = argUserName;
    }
    public String getRoll() {
        return this.roll;
    }
    public void setRoll(String argRoll) {
        roll = argRoll;
    }
    public String getEmail() {
        return this.email;
    }
    public void setEmail(String argEmail) {
        email = argEmail;
    }
    public String getSection() {
        return this.section;
    }
    public void setSection(String argSection) {
        section = argSection;
    }
    public String getStdClass() {
        return this.stdClass;
    }
    public void setStdClass(String argStdClass) {
        stdClass = argStdClass;
    }
    public List getSubscriptionOptions() {
        return subscriptionOptions;
    }
    public void setSubscriptionOptions(List argSubscriptionOptions) {
        subscriptionOptions = argSubscriptionOptions;
    }
    public void setNewsLetterOption(boolean argNewsLetterOption) {
        newsLetterOption = argNewsLetterOption;
    }
    public boolean getNewsLetterOption() {
        return newsLetterOption;
    }
    public void setConsentOptions(List argConsentOptions) {
        consentOptions = argConsentOptions;
    }
    public List getConsentOptions() {
        return consentOptions;
    }
}


In order to understand how these beans are defined in the struts.xml
configuration file, as shown below:

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="hibernate-example" namespace="/sample"
                 extends="struts-default">
        <action name="example" class="sample.ExamplePOJOAction" 
                               method="preview">
                <result name="preview">/preview.jsp</result>
                <result name="input">/index.jsp</result>
        </action>
    </package>
</struts>



So we have two JSPs for showing UI for this example.
index.jsp file is the main JSP file that is called when browser is requesting
for the default main screen, and on click of the submit button, validation 
for the action ExamplePOJOAction will be invoked. Appropriate error message
will be shown on screen with the message from the validation XML file.

Once the correct value for the STD/class text field is entered, for this
example it is any word using I, V or X letters only, the preview screen
will be called.

Some of the other files require to run this example as follows:


index.jsp

<%@ taglib uri="/struts-tags" prefix="struts2"%>
<html>
<head>
<link rel="stylesheet" type="text/css" href="sample.css" />
</head>
<body>
<struts2:actionerror cssClass="ss"/>
<struts2:bean id="so" name="sample.SubscriptionOptions"/>
<struts2:bean id="consentOption" name="sample.ConsentOptions"/>
<struts2:form method="post" action="example" namespace="/sample">
<table>
<tr><td><struts2:textfield key="myBean.userName" label="Name "/></td></tr>
<tr><struts2:textfield key="myBean.roll" label="Roll "/></td></tr>
<tr><struts2:textfield key="myBean.email" label="Email "/></td></tr>
<tr><td><struts2:textfield key="myBean.section" label="Section "/></td></tr>
<tr><struts2:textfield key="myBean.stdClass" label="Std/Class "/></td></tr>
<struts2:checkbox key="myBean.newsLetterOption" label="Subscription for News Letters "/>
<struts2:checkboxlist label="Other Subscription Options " key="myBean.subscriptionOptions" list="so" labelSeparator=":"/>
<struts2:radio label="You opinion " key="myBean.consentOptions" list="consentOption" labelSeparator=":"/>
<tr><td colspan="2"><struts2:submit value="Register"/></td></tr>
</table>
</struts2:form>
</body>
</html>


preview.jsp

<%@ taglib uri="/struts-tags" prefix="struts2"%>
<html>
<head></head>
<body>
<h2>Preview Page</h2>
<table>
<tr><td>
<b><font color="green">Name : </font>
</td><td><struts2:property value="myBean.userName"/></td></tr>
<tr><td><b><font color="green">Roll No. : </font></b></td><td>
<struts2:property value="myBean.roll"/></td></tr>
<tr><td><b><font color="green">Email : </font></b></td><td>
<struts2:property value="myBean.email"/></td></tr>
<tr><td><b><font color="green">Section : </font>
</b></td><td><struts2:property value="myBean.section"/></td></tr>
<tr><td><b><font color="green">Std/Class : </font>
</b></td><td><struts2:property value="myBean.stdClass"/></td></tr>
<tr><td>
<b><font color="green">New Letter Subscription :</font></b></td><td>
<struts2:if test="myBean.newsLetterOption">
Yes
</struts2:if>
<struts2:else>
No
</struts2:else>
</td></tr>
<tr><td valign="top"><b><font color="green">Other Subscription Options:</font></b></td><td>
<struts2:iterator id="a" value="myBean.subscriptionOptions">
<struts2:property value="a"/>
<br>
</struts2:iterator>
</td></tr>

<tr><td valign="top"><b><font color="green">User consent Option selected :</font></b></td><td>
<struts2:iterator id="b" value="myBean.consentOptions">
<struts2:property value="b"/>
<br>
</struts2:iterator>
</td></tr>

</table>
</body>
</html>



Some of the user defined values for showing subscription options
and consent options on screen are

SubscriptionOptions.java

package sample;
import java.util.ArrayList;

public class SubscriptionOptions extends ArrayList
{
        public SubscriptionOptions() {
          super();
          add("Technical Support");
          add("Business Support");
          add("HR Support");
          add("Help Desk Emails");
        }
}


ConsentOptions.java

package sample;
import java.util.ArrayList;

public class ConsentOptions extends ArrayList
{
	public ConsentOptions() {
          super();
          add("Agree");
          add("Disagree");
	}
}


And the Web application descriptor XML file for this example is:
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>
    <display-name>Struts Blank</display-name>
  <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>


List of JAR file with version those are used in this example as follows:
struts2-core-2.1.6.jar
xwork-2.1.2.jar
ognl-2.6.11.jar
freemarker-2.3.13.jar
commons-logging-1.1.jar
commons-io-1.3.2.jar
commons-fileupload-1.2.1.jar

Eclise 3.2 is used as IDE and Apache Jakarta Tomcat 5.5.9 as web server.

If anything missed out , please let me know at
techienjoy at yahoo . com