Optional and empty fields are validated

[cardel.ka.jelinek.seznam.cz]

Hi,
I am using Seam 2.0.1 GA, JSF 1.2 and Hibernate 3.2.4
In my application I am using @Email and @Length annotations on my User entity:

@Entity
@Table(name = "users")
public class User implements Serializable {

private String email;
private String city;
 
@Email
public String getEmail() {
  return email;
}

public void setEmail(String email) {
  this.email = email;
} 

@Length(min=2,max=25)
public String getCity() {
  return city;
}

public void setCity(String city) {
  this.city = city;
}

It is working fine. When field with email or city has incorrect form, validation message is showed. But if I am keep these fields empty, then I am getting Hibernate exception:

 org.hibernate.validator.InvalidStateException: validation failed for: hcp.User

But this fields has to be optional. I read somewhere, that validation is made only if fields in JSF are not empty. But in my case, validation is fired every time.

In JSF form I am using s:validate tag. Fields are set as no required.

<h:outputLabel for="emailInput">Email</h:outputLabel>
<a:outputPanel id="emailPanel">
     <s:decorate>
          <h:inputText id="emailInput" value="#{user.email}"
               styleClass="text" >
               <a:support event="onblur" reRender="emailPanel"
                    ajaxSingle="true" />
          <s:validate />
          </h:inputText>
          <h:message for="emailInput" errorClass="error" />
     </s:decorate>
</a:outputPanel>

<h:outputLabel for="cityInput">City</h:outputLabel>
<a:outputPanel id="cityPanel">
     <s:decorate>
          <h:inputText id="cityInput" value="#{user.city}"
               styleClass="text" >
               <a:support event="onblur" reRender="cityPanel"
                    ajaxSingle="true" />
          <s:validate />
          </h:inputText>
          <h:message for="cityInput" errorClass="error" />
     </s:decorate>
</a:outputPanel>

I solved storing null email value to DB with this 'hack' before persisting.

if (this.getEmail().equalsIgnoreCase(""))
this.setEmail(null);

But then I found out, that the same problem is with all optional fields, that have some hibernate validation tag.

Any help or hint how to use optional fields with validation?

[matt.drees]

Take a look at this for a starting point; I think it's the best way to solve this sort of problem.

He doesn't explicitly say this, but in jsf 1.2 you can use the converter-for-class attribute to specify that this converter should be used for all Strings.

[cardel.ka.jelinek.seznam.cz]

Yes! Thanks, this is good solution.