Using the AlloyUI Validator Tag

The AlloyUI validator tag is a handy way to make sure users enter the right data into a form’s AlloyUI input fields. It offers multiple data checks, making form validation a simple task. This tutorial covers using the aui:validator tag in your portlets. AlloyUI also offers a comprehensive form validator module that incorporates much of what is covered in this tutorial. See the AlloyUI Form Validator tutorial to learn more about it.

Setting Up the AlloyUI Validator Tag

It doesn’t take much to get the aui:validator tag working.

  • Step 1: Reference the AUI Taglib.
  • Step 2: Configure the Form in the View JSP.
  • Step 3: Insert and Configure the AUI validator Tag in the View JSP.

The example below uses these steps to implement AlloyUI input field validation in a portlet. Follow along and you’ll be validating in no time!

Step 1: Reference the AUI Taglib

First you need to make sure that you’ve referenced the aui taglib in your JSP. If you’re already using AlloyUI tags in your JSP, then you can skip this step. If you’re not, open or create your portlet’s view.jsp. Add the aui taglib declaration:

<%@ taglib prefix="aui" uri="" %>

Just like that you’re ready to use the AUI tags in your portlet. Onward to the next step!

Step 2: Set Up the Form and Input Fields

If you don’t yet have an AlloyUI form with input fields then you need to create one. Add the aui:form tag to the bottom of the view.jsp and place your input fields inside. It should look similar to the example here:

<aui:form name="myForm" action="" method="post">
    <aui:input name="Name" value="" label="Name">


Repeat this step to add as many input fields as you need for your form. You’re almost done! Onwards to the last step!

Step 3: Insert and Configure the AUI Validator Tag in the View JSP

The final step is where you actually implement the field validation. This is straightforward but there are a few things to keep in mind. Still inside the view.jsp, nest the aui:validator tag in the input field that you want to validate. The following code illustrates the basic structure of the aui:validator tag. While only a single validation rule is implemented here, you can add several if you wish:

<aui:form name="myForm" action="" method="post">
    <aui:input name="Name" value="" label="Name">
        <aui:validator name="required" />

In this example the name attribute of the aui:validator tag marks the surrounding input field as required. If you deploy your portlet and try to leave the field blank, you receive the default error message, “This field is required.” The figure here shows what this error message looks like.


Figure 1: The default error message when a required field is left blank.

If you want to override the default error message, add an errorMessage attribute to the aui:validator tag:

<aui:validator name="alpha" errorMessage="Enter characters that exist in the alphabet next time, please." />

As you can see, you can have a lot of fun customizing your error messages. Note that "alpha" is used as the validation rule to restrict users to alphabetic characters for that field. Next, the full list of values available for the name attribute of the aui:validator tag are presented.

Available Validation Rules

There are several validation rules that you can implement for your input fields. As shown in the previous example, this is done by choosing different values for the name attribute of the aui:validator tag:

acceptFiles: Specifies that the field can contain only the file types given. Each file extension must be separated by a comma. For example <aui:validator name="acceptFiles">'jpg,png,tif,gif'</aui:validator>

alpha: Allows only alphabetic characters.

alphanum: Allows only alphanumeric characters.

date: Allows only a date.

digits: Allows only digits.

email: Allows only an email address.

equalTo: Allows only contents equal some other field that has the specified field ID. The ID is declared in the opening and closing validator tags. For example <aui:validator name="equalTo">'#<portlet:namespace />password'</aui:validator>

max: Allows only an integer value less than the specified value. For example, a max value of 20 is specified here <aui:validator name="max">20</aui:validator>

maxLength: Allows a maximum field length of the specified size. The syntax is the same as max.

min: Allows only an integer value greater than the specified value. The syntax is the same as max.

minLength: Allows a field length longer than the specified size. The syntax is the same as max.

number: Allows only numerical values.

range: Allows only a number between the specified range. For example, a range between 1.23 and 10 is specified here <aui:validator name="range">[1.23,10]</aui:validator>

rangeLength: Allows a field length between the specified range. For example, a range between 3 and 8 characters long is specified here <aui:validator name="rangeLength">[3,8]</aui:validator>

required: Prevents a blank field.

url: Allows only a URL value.

Below is a view.jsp that uses several of the validation rules discussed above. The "Name" input field is required and restricted to alphabetic characters. A custom error message that informs the user of this is also specified. Additionally, the "Email" field is required and must be in the form of an email address:

<%@ taglib uri="" prefix="portlet" %>
<%@ taglib uri="" prefix="aui" %>

<portlet:defineObjects />

<aui:form name="myForm" action="" method="post">
    <aui:input name="Name" value="" label="Name">
        <aui:validator name="required"/>
        <aui:validator name="alpha" errorMessage="Enter characters that exist in the alphabet next time please"/>
    <aui:input name="Email" value="" label="Email">
        <aui:validator name="required"/>
        <aui:validator name="email"/>
    <aui:button type="submit" name="submit" value="submit" />

Below is what a finished portlet could look like with the error messages triggered:


Figure 2: Here’s an example of a finished portlet that uses the above code.

The custom error message is supplied as a string at the moment. As this is not best practice, you should supply the custom error message via a language key. You’ll take care of this next.

Creating a Language Key Hook for the Error Message

In order to supply the language key for the custom error message you will need to create a hook.

Follow the steps below to create the language key hook:

  1. Goto FileNewLiferay Plugin Project.

  2. Set the Project name as aui-validator-language-hook and Display name as Aui Validator Language Hook.

  3. Set the proper SDK and runtime, select Hook for the Plugin type, and click Finish.

    The skeleton for the hook is complete. Now you need to configure the hook to modify the existing language properties. In this case you’ll be modifying the English US language properties, but the process can be used to hook into any existing language properties file.

  4. Right-click the language key hook you just created in the package explorer on the left and select NewLiferay Hook Configuration.

  5. With aui-validator-language-hook set as the Hook plugin project select Language properties for the hook type and click Next.

  6. Leave the default Content folder and click Add.

  7. Enter for the property file, click OK and Finish.

  8. Open the docroot/WEB-INF/src folder of the aui-validator-language-hook and open the file in the content package.

  9. Add the following language key to the file and Save it:

    characters-that-exist = Enter characters that exist in the alphabet next time please

    Now that you have the language key defined you can update the tag to use it.

  10. In your view.jsp, update the aui:validator tag to look like the following code:

    <aui:validator name="alpha" errorMessage="characters-that-exist"/>
  11. Redeploy the portlet, leave the Name field blank, and submit the form. The error message now uses the language key you just created!

Congrats! Now you know how to use the aui:validator tag. As you can see, it gives you a lot of control over what your users can enter in input fields.

Related Topics

User Interfaces with the Liferay UI Taglib

Themes and Layout Templates

Application Display Templates

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