How To Add a TwoFields Validator

In the Struts Validator Guide, there is a section on how to create a pluggable validator that matches two fields. I've been using this server-side validator (as shown in the example) to do password/confirm password validation. This has worked great for me, but I've always wanted the Validator to have the client-side JavaScript method for it too. I wrote my own that just compared the two fields, but it's not the same as having one rendered for you (from validator-rules.xml). So yesterday, I did some tinkering and figured out how to add the JavaScript method to validator-rules.xml. So here's how to configure the whole thing (most of this is contained in the Validator Guide, save the JavaScript).

How To Add a TwoFields Validator

Step 1: Create a class with a validateTwoFields method. In my code, my class is ValidationUtil and has the following method:

public static boolean validateTwoFields(Object bean, ValidatorAction va,                                        Field field, ActionErrors errors,                                        HttpServletRequest request) {    String value =        ValidatorUtil.getValueAsString(bean, field.getProperty());    String sProperty2 = field.getVarValue("secondProperty");    String value2 = ValidatorUtil.getValueAsString(bean, sProperty2);    if (!GenericValidator.isBlankOrNull(value)) {        try {            if (!value.equals(value2)) {                errors.add(field.getKey(),                           Resources.getActionError(request, va, field));                return false;            }        } catch (Exception e) {            errors.add(field.getKey(),                       Resources.getActionError(request, va, field));            return false;        }    }    return true;}

Step 2: Edit validator-rules.xml to contain the "twofields" rule.

<validator name="twofields"     classname="org.appfuse.webapp.util.ValidationUtil" method="validateTwoFields"     methodParams="java.lang.Object,                  org.apache.commons.validator.ValidatorAction,                  org.apache.commons.validator.Field,                  org.apache.struts.action.ActionErrors,                  javax.servlet.http.HttpServletRequest"    depends="required" msg="errors.twofields">    <javascript><![CDATA[        function validateTwoFields(form) {            var bValid = true;            var focusField = null;            var i = 0;            var fields = new Array();            oTwoFields = new twofields();            for (x in oTwoFields) {                var field = form[oTwoFields[x][0]];                var secondField = form[oTwoFields[x][2]("secondProperty")];                            if (field.type == 'text' ||                    field.type == 'textarea' ||                    field.type == 'select-one' ||                    field.type == 'radio' ||                    field.type == 'password') {                                var value;                    var secondValue;                    // get field's value                    if (field.type == "select-one") {                        var si = field.selectedIndex;                        value = field.options[si].value;                        secondValue = secondField.options[si].value;                    } else {                        value = field.value;                        secondValue = secondField.value;                    }                                    if (value != secondValue) {                                            if (i == 0) {                            focusField = field;                        }                        fields[i++] = oTwoFields[x][1];                        bValid = false;                    }                }            }                        if (fields.length > 0) {                focusField.focus();                alert(fields.join('/n'));            }                        return bValid;        }]]></javascript></validator>

Step 3: Configure validation for your form in validation.xml:

<field property="password"     depends="required,twofields">  <msg    name="required"    key="errors.required"/>  <msg    name="twofields"    key="errors.twofields"/>  <arg0 key="userForm.password"/>  <arg1    key="userForm.confirmPassword"  />  <var>    <var-name>secondProperty</var-name>    <var-value>confirmPassword</var-value>  </var></field>

Where errors.twofields=The '{0}' field has to have the same value as the '{1}' field. An alternative to Step 3 is to use XDoclet to generate your validation.xml. This requires (1) configuring XDoclet (of course) and (2) adding some @struts tags to your form on the setPassword method.

/** * Returns the password. * @return String * * @struts.validator type="required" msgkey="errors.required" * @struts.validator type="twofields" msgkey="errors.twofields" * @struts.validator-args arg1resource="userForm.password" * @struts.validator-args arg1resource="userForm.confirmPassword" * @struts.validator-var name="secondProperty" value="confirmPassword" */public String setPassword() {return password;}

I've sent this as a proposal to the struts-dev mailing list yesterday, but haven't heard anything yet. Enjoy!

Update: You'll need to update ValidationUtil.java and validator-rules-custom.xml for Struts 1.2. Full files: ValidationUtil.java and validation-rules-custom.xml. February 26, 2003 12:29 PM MST Permalink

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