Understanding public void prepare() +tiles

[E Robb]

I have a tiles layout and I want the initial display to use prepare() in the page to populate a field.

If I use prepare() and specify the action then validation is run when the page is initally loaded. Validation errors are returned. If I dont specify result type an error is thrown by Struts.

Bottom line is I want to use one action to set the variables the page may need and the same action execute the page. I dont want multiple actions for every page unless there is a good reason.

Struts.xml:

	<!-- Security update rendered and preloaded using prepare-->    
	<package name="security.tiles" extends="tiles-default" namespace="/candidate"> 
	     <action name="security" class="common.Security">
			<result type="tiles">/candidate/security.tiles</result> 
	     </action>
	      
	     <!-- run the action an validate -->
	     <action name="security_update" class="common.Security"> 
	     	 <result type="tiles" name="input">/candidate/security.tiles</result> 
	         <result type="tiles" name="success">/candidate/security.tiles</result> 
	         <result type="tiles" name="failure">/candidate/security.tiles</result> 
	     </action>       
	 </package>

Simple action common.Security:

import com.opensymphony.xwork2.Preparable;
import actionsupport.GlobalActionSupport;

public class Security extends GlobalActionSupport implements Preparable{
	private static final long serialVersionUID = 1L;

    public void prepare(){
    	System.out.print("LETS PREPARE OUR PAGE");
		setUsername("testuser");
    }

	public String execute(){
		System.out.print("Execute the code");
		return "success";
	}

 }

Validation.xml:

<!DOCTYPE validators PUBLIC
        "-//OpenSymphony Group//XWork Validator 1.0.2//EN"
        "http://www.opensymphony.com/xwork/xwork-validator-1.0.2.dtd">

<validators>
    <field name="oldpassword">
        <field-validator type="requiredstring">
            <message key="MSG_SECURITY_PWD_INCORRECT"/>
        </field-validator>
    </field>
     <field name="newpassword">
        <field-validator type="requiredstring" short-circuit="true">
            <message key="password.requiredString"/>
        </field-validator>
		<field-validator type="stringlength">
            <param name="minLength">6</param> 
            <param name="maxLength">16</param> 
			<message key="MSG_SECURITY_PWD_LENGTH"/>
		</field-validator>
    </field>
     <field name="newpassword_confirm">
        <field-validator type="requiredstring" short-circuit="true">
            <message key="password.requiredString"/>
        </field-validator>
		<field-validator type="fieldexpression">
			<param name="fieldName">newpassword_confirm</param>
			<param name="expression">newpassword.equals(newpassword_confirm)</param>       
			<message key="MSG_SECURITY_PWD_NO_MATCH"/>
		</field-validator>
    </field>
</validators>