JSF: a regular expression validator
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
- 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;
}
}
- 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;
}
}
- 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>
- 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>
- 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"/>
<f:validator validatorId="registerValidator"/>
</h:inputText>
<h:message for="firstName"/>
25 Mar 2004 |
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