JSF validateLength Tag
If you want the user to input the number of characters between the certain range, suppose you want the user to fill password of more than 6 characters then this tag can be used to validate. This is one of the standard validators provided by JSF to check whether the length of the local value entered in the corresponding input component is within the certain range. This range is specified by minimum and maximum attributes of this tag. The page author requires no code to write for validation. Simply use this tag in the nearest enclosing input component. If there is any fault in filling the input component then the error message flashes to show this error. In the following example, the user has entered less than 6 characters in the password field so error message displaying that user has entered less than 6 characters in the password field.
Code Description :
| <%@ taglib uri="http://java.sun.com/jsf/html" prefix="h"%> <%@ taglib uri="http://java.sun.com/jsf/core" prefix="f"%> <f:view> <html> <body> <h:form><h:outputText value="ID"/><br> <h:inputText id="ID" value="#{MessageBean.a}" required="true"/> <h:message for="ID"/> <br><br> <h:outputText value="PASSWORD(minimum 6 characters)"/><br> <h:inputSecret id="PWD" value="#{MessageBean.b}" required="true" > <f:validateLength maximum="15" minimum="6"/> </h:inputSecret> <h:message for="PWD"/> <br><br> <h:commandButton value="submit" /> </h:form> </body> </html> </f:view> |
Rendered Output :
This is the first screen that will be rendered to the user.
When the user enters the value less than 6 characters or more than 15 characters then validation error is displayed specifying that the user has not entered the correct value. Figure below shows this fact :
Html Source Code :
| <html> <body> <form id="_id0" method="post" action="/coretag/pages/validateLength.jsf" enctype="application/x-www-form-urlencoded"> ID<br> <input id="_id0:ID" type="text" name="_id0:ID" value="" /> <br><br> PASSWORD(minimum 6 characters)<br> <input id="_id0:PWD" type="password" name="_id0:PWD" value="" /> <br><br> <input type="submit" name="_id0:_id5" value="submit" /> <input type="hidden" name="_id0" value="_id0" /></form> </body> </html> |
This tag contains two attributes :
maximum : This attribute is used to set the
maximum length allowed for this component to input
minimum : This is used to set the minimum length allowed to be entered in
the component.