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layout: core-developers title: requiredstring validator parent: title: Validation url: validation.html

requiredstring validator

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Description

RequiredStringValidator checks that a String field is non-null and has a length > 0. (i.e. it isn't ""). The trim parameter determines whether it will String#trim() the String before performing the length check. If unspecified, the String will be trimmed.

Parameters

• fieldName - The field name this validator is validating. Required if using Plain-Validator Syntax otherwise not required.
• trim - (Optional) Boolean, default true. Trims the field name value before validating.
• trimExpression - (Optional) String. Specifies the trim param as an OGNL expression.

Examples

<validators>
    <!-- Plain-Validator Syntax -->
    <validator type="requiredstring">
        <param name="fieldName">username</param>
        <param name="trim">true</param>
        <message>username is required</message>
    </validator>
     
    <!-- Field-Validator Syntax -->
    <field name="username">
        <field-validator type="requiredstring">
            <param name="trim">true</param>
            <message>username is required</message>
        </field-validator>
    </field>
 
    <!-- Field-Validator Syntax with expression -->
    <field name="username">
        <field-validator type="requiredstring">
            <param name="trimExpression">${trimValue}</param> <!-- will be evaluated as: boolean getTrimValue() -->
            <message>username is required</message>
        </field-validator>
    </field>
</validators>