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In the Using Tags lesson, we implemented a Logon form. In the Coding Actions lesson, we interpret the Logon form, and return a different result code depending on the circumstances.

If you have coded along, you can open the Logon action

Code Block
http://localhost:8080/tutorial/Logon.action

and enter a likely username and password. Since we haven't given the Action any behavior, the mapping redisplays the default Logon.jsp page.

Let's add an Action class that will make the Logon form more interesting.

The Code

Just as an example, we can examine the username and password values. If either or both properties are empty, return INPUT, so that we can collect a valid Logon. Otherwise, return SUCCESS.

Code Block

format	xml
title	Logon.java
borderStyle	solid


package tutorial;

Actions

we will create a form in which you can enter your name. For example, if you enter "Bob" and click the submit button,
you'll get a page saying "Hello, Bob!". If you don't enter a name, you'll get a screen saying: "Hmm, you don't seem to have entered a name. Go back and try again please."

As before, we set everything up in four steps: create the form, create the action, register the action, and create the landing page (or in this case, pages).

1. Create the form

Wiki Markup
Paste this html into \[webapp\]/page03.jsp:

...


<html>
<head>
	<title>A simple form with data</title>
</head>
<body>
	<p>What is your name?</p>

	<form action="form03.action" method="post">
		<p><input type="text" name="yourName"></p>
		<p><input type="submit" value="Submit your name." /></p>
	</form>

</body>
</html>

2. Create the form action

Wiki Markup
Paste this code into \[src\]/lessons/Form03Action.java:

Code Block

java


package lessons;

import com.opensymphony.xworkxwork2.ActionSupport;

public class Form03ActionLogon extends ActionSupport {

  String yourName;

  public voidString setYourNameexecute(String p_yourName)) throws Exception {
    yourName = p_yourName;
  }

  public String getYourName() {
    return yourNameif (isInvalid(getUsername())) return INPUT;
  }


  public String execute() throws Exception {
    if (yourName == null || yourName.length() == 0)
      return ERROR(isInvalid(getPassword())) return INPUT;
    else
      return SUCCESS;
  }

}

3. Register the action in xwork.xml:

...


<!DOCTYPE xwork PUBLIC "-//OpenSymphony Group//XWork 1.0//EN"
"http://www.opensymphony.com/xwork/xwork-1.0.dtd">

<xwork>
  <!-- Include webwork defaults (from WebWork JAR). -->
  <include file="webwork-default.xml" />
  
  <!-- Configuration for the default package. -->
  <package name="default" extends="webwork-default">
    <!-- Default interceptor stack. --> 
    <default-interceptor-ref name="defaultStack" /> 
    
    <!-- 02 --> 
    <action name="form02" class="lessons.Form02Action"> 
      <result name="success" type="dispatcher">page02-success.jsp</result> 
    </action> 

    <!-- 03 -->
    <action name="form03" class="lessons.Form03Action">
      <result name="success" type="dispatcher">page03-success.jsp</result>
      <result name="error" type="dispatcher">page03-error.jsp</result>
    </action>

  </package>
</xwork>

4. Create the success and error pages

Wiki Markup
Create \[webapp\]/page03-success.jsp:

...


<%@ taglib uri="webwork" prefix="ww" %>
<html>
<head>
	<title>Success page for form with data</title>
</head>
<body>

Hello, <ww:property value="yourName" />!

</body>
</html>

Wiki Markup
Create \[webapp\]/page03-error.jsp:

...


<html>
<head>
	<title>Error page for form with data</title>
</head>
<body>

Hmm, you don't seem to have entered a name. Go back and try again please.

</body>
</html>

 }

    private boolean isInvalid(String value) {
        return (value == null || value.length() == 0);
    }

    private String username;
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }

    private String password;
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }

}

How The Code Works

The framework automatically populates the username and password properties for us. All that's left to do is checking to see if either property is empty.

What to Remember

The Actions do the "heavy lifting" in a web application. Actions interact with data base systems and business rule engines, so that we can turn "billboard" HTML into a rich, dynamic web experience.

After doing its work, an Action returns a result code to indicate what the framework should do next. Often, the next step is to go onto the "success" result. Other times, we might need to go to an "error" result instead. In either case, the Action does not worry about generating the response, only deciding which logical result to present next.

For more about Actions, see Big Picture in the Core Developers Guide.

Next	Onward to Selecting Results
Prev	Return to Using Tags

Try it

Wiki Markup
Don't forget to compile your action to \[webapp\]/WEB-INF/classes, and to restart your web application if necessary.

Go ahead and try it now: click the form submit button and see what happens. Try it with and without entering a name.

How the code works

There are only two differences between this example and the previous lesson.

When the action is called, its setYourName() setter is called with the contents of the form field named yourName.
After the action has been called (which is when its execute() method returns), WebWork has two options. If ERROR is returned, WebWork will return page03-error.jsp; if SUCCESS, page03-success.jsp. Just as in the last lesson, the <ww:property> tag calls the action's getter (in this case, getYourName()).

...

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