Syboos Commons BeanUtils validators - ValidateRequired

    @ValidateRequired
    private String value;

    public String getValue() {
        return value;
    }
    public void setValue(String value) {
        this.value = value;
    }

    @ValidateRequired(when="login", message="value is required")
    private String value;

    ...

<field name="value">
    <validator class="com.syboos.beanutils.validator.RequiredValidator" message="value is required" />
</field>