Andrej Koelewijn

Continuing my example from a few days back, this example shows how to create a JSF validator tag which checks agains a regular expression.

Step 5: custom validator tag

1. Add validator class
   
   

   package jsftest1;
   
   import javax.faces.application.FacesMessage;
   import javax.faces.component.UIComponent;
   import javax.faces.context.FacesContext;
   import javax.faces.validator.Validator;
   import javax.faces.validator.ValidatorException;
   
   public class RegExValidator implements
    Validator {
   
    String regex;
   
    public void validate(
    FacesContext _context,
    UIComponent _component,
    Object _value)
    throws ValidatorException {
   
    String val = (String) _value;
    if (!val.matches(regex)) { 
    throw new ValidatorException(
    new FacesMessage(
    "Incorrect value, does not match regular expression: "
    + regex)); }
   
    }
   
    public String getRegex() {
    return regex;
    }
   
    public void setRegex(String regex) {
    this.regex = regex;
    }
   }

   
   


2. Add validator tag class
   
   

   package jsftest1;
   
   import javax.faces.validator.Validator;
   import javax.faces.webapp.ValidatorTag;
   import javax.servlet.jsp.JspException;
   
   public class RegExValidatorTag extends
    ValidatorTag {
   
    private String regex;
    
    public RegExValidatorTag(){
    super();
    super.setValidatorId("regexValidator");
    }
   
    protected Validator createValidator()
    throws JspException {
    RegExValidator result = null;
    result = (RegExValidator)super.createValidator();
    result.setRegex(regex);
    return result;
    }
   
    public String getRegex() {
    return regex;
    }
   
    public void setRegex(String regex) {
    this.regex = regex;
    }
   }

   
   


3. Add tag lib descriptor file
   <PROJECT_HOME>/web/WEB-INF/jsftest1.tld
   
   

   <taglib>
    <tlibversion>0.1</tlibversion>
    <jspversion>2.0</jspversion>
    <shortname>JSF test 1 taglib</shortname>
    <tag>
    <name>regexValidator</name>
    <tagclass>jsftest1.RegExValidatorTag</tagclass>
    <attribute>
    <name>regex</name>
    <required>true</required>
    <rtexprvalue>false</rtexprvalue>
    </attribute>
    </tag>
   </taglib>

   
   


4. Add validator to faces-config.xml
   
   

    <validator>
    <validator-id>regexValidator</validator-id>
    <validator-class>jsftest1.RegExValidator</validator-class>
    <attribute>
    <attribute-name>regex</attribute-name>
    <attribute-class>java.lang.String</attribute-class>
    </attribute>
    </validator>

   
   


5. Modify jsp page
   
   

    
   <h:outputLabel for="firstName">
    <h:outputText value="#{bundle.firstName}"/> 
   </h:outputLabel>
   <h:inputText id="firstName" value="#{registerBean.firstName}" >
    <f:validateLength minimum="1"/>
    
   style="font-weight: bold;"><j:regexValidator regex="[A-Z]+"/>
    <f:validator validatorId="registerValidator"/>
   </h:inputText>
   <h:message for="firstName"/>