Working on Tapestry Validation

[Gregg Bolinger]

Ok, I have moved on to try and get a grasp of the validation in Tapestry down. And I need a bit of clarification.

I have a login form that consists of a username and a password field. All I want to do initially is specify that these fields are required. Originally, my Login.page looked like this:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE page-specification
      PUBLIC "-//Apache Software Foundation//Tapestry Specification 3.0//EN"
      "http://jakarta.apache.org/tapestry/dtd/Tapestry_3_0.dtd">
 
<page-specification class="examples.Login">
    <property-specification name="message" type="java.lang.String"/>
    <property-specification name="username" type="java.lang.String"/>
    <property-specification name="password" type="java.lang.String"/>
</page-specification>

So, the first change I started to make was to declare a bean called "delegate" and noticed I needed to define my own class for this. This is confusion #1.

The next change I needed to make was to add a bean declaration called "required" that used a class StringValidator. No problem.

Confusion #2: I then needed to add a component declaration for my ValidField. This was pretty self explanitory until I got to the part where I say something like:

<binding name="value" expression="???" />

The book has a JavaBean which it uses for this purpose. I am just creating a Login form. I don't want to code a bean just for this. I thought that there should be someway to specify this from the following property-specification:

<property-specification name="username" type="java.lang.String"/>

But I am not sure if this is a) possible and b) how I would do it if it is possible.

Note also that the delegate class I need to define would handle the changes made to the html like change the color of the FieldLabel and even highlight the textfield bla bla. I don't really care about this right now. All I care about is notifying the user that the fields are required. So is there a class that I can specify for that delegate that is already in the Tapestry API rather than having to create my own and extend ValidationDelegate?

I hope this made some sense. I have to abuse Howard and Geoff and all the other experts before the promo is over and they all leave.
[ May 26, 2004: Message edited by: Gregg Bolinger ]

[Looluo Zhu]

confusion #1
You can use org.apache.tapestry.valid.ValidationDelegate that is already in the Tapestry API.

confusion #2
You can do just like this:

<binding name="value" expression="username"/>

After the form is rewinded, the property "username" of the Login page will be set.

[Gregg Bolinger]

Originally posted by Looluo Zhu:
confusion #1
You can use org.apache.tapestry.valid.ValidationDelegate that is already in the Tapestry API.

confusion #2
You can do just like this:

<binding name="value" expression="username"/>

After the form is rewinded, the property "username" of the Login page will be set.

Great! Thanks Looluo. I appreciate the help. I'm sure I'll be back with more questions on this.

[Gregg Bolinger]

Ok, problems I am running into now...

I have the following Login.page

<page-specification class="examples.Login">
    
    <property-specification name="message" type="java.lang.String"/>
    <property-specification name="username" type="java.lang.String"/>
    <property-specification name="password" type="java.lang.String"/>
    
    <bean name="delegate" class="org.apache.tapestry.valid.ValidationDelegate"/>
    <bean name="required" class="org.apache.tapestry.valid.StringValidator"
        lifecycle="page">
        <set-property name="required" expression="true"/>
    </bean>
    
    <component id="inputUserName" type="ValidField">
        <static-binding name="displayName" value="Username"/>
        <binding name="validator" expression="beans.required"/>
        <binding name="value" expression="username"/>
    </component>
    
    
</page-specification>

And relevent part of my Login.html

<span jwcid="@FieldLabel" field="ognl:components.inputUserName">Username</span>
<input type="text" jwcid="inputUserName" class="textbox"/>

And here is my Login.java

package examples;
 
import org.apache.tapestry.html.BasePage;
import org.apache.tapestry.IRequestCycle;
 
public abstract class Login extends BasePage 
{
public abstract String getUserName();
public abstract String getPassword();
public abstract void setMessage(String message);

public void login(IRequestCycle cycle)
{

if (isValidLogin(getUserName(), getPassword()))
{
cycle.activate("EmployeeSearch");
return;
}
setMessage("Invalid user name or password");
}

private boolean isValidLogin(String userName, String password)
{
return "tapestry".equalsIgnoreCase(userName);
}
 
}

The error I am getting is:

Method 'public abstract java.lang.String examples.Login.getUserName()' (declared in class examples.Login) has no implementation in class examples.Login (or enhanced subclass examples.Login$Enhance_3).

Now before I started with the validation stuff, my Login.html was a little different. For the input of the username I had the following line:

<input type="text" jwcid="@TextField" value="ognl:userName" size="30" class="textbox"/>

I know how this worked. The ognl:userName was used to use the abstract method getUserName() in my Login.java class. So I am assuming my error is because of the difference between the 2 files now but I am unclear on how to correct this.

Thanks.

[Gregg Bolinger]

When I added the property-specification for username back into my Login.page I typed it as username instead of userName



I haven't put the validation back in to test it yet, but I assume at least my original problem will go away