Cross field validation with Hibernate Validator JSR 303

Question

Is there an implementation of  or third-party implementation for  cross field validation in Hibernate Validator 4 x  If not  what is the cleanest way to implement a cross field validator   As an example  how can you use the API to validate two bean properties are equal  such as validating a password field matches the password verify field    In annotations  I d expect something like   public class MyBean      Size min 6  max 50    private String pass      Equals property  pass     private String passVerify

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If you   re using the Spring Framework then you can use the Spring Expression Language  SpEL  for that  I   ve wrote a small library that provides JSR-303 validator based on SpEL     it makes cross-field validations a breeze  Take a look at https   github com jirutka validator-spring   This will validate length and equality of the password fields      SpELAssert value    pass equals passVerify                message     validator passwords not same    public class MyBean         Size min   6  max   50      private String pass       private String passVerify      You can also easily modify this to validate the password fields only when not both empty    SpELAssert value    pass equals passVerify                applyIf    pass    passVerify               message     validator passwords not same    public class MyBean         Size min   6  max   50      private String pass       private String passVerify

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Cross fields validations can be done by creating custom constraints    Example - Compare password and confirmPassword fields of User instance   CompareStrings     Target  TYPE    Retention RUNTIME   Constraint validatedBy CompareStringsValidator class   Documented public  interface CompareStrings       String   propertyNames        StringComparisonMode matchMode   default EQUAL      boolean allowNull   default false      String message   default         Class lt   gt    groups   default         Class lt   extends Payload gt    payload   default         StringComparisonMode  public enum StringComparisonMode       EQUAL  EQUAL IGNORE CASE  NOT EQUAL  NOT EQUAL IGNORE CASE     CompareStringsValidator   public class CompareStringsValidator implements ConstraintValidator lt CompareStrings  Object gt         private String   propertyNames      private StringComparisonMode comparisonMode      private boolean allowNull        Override     public void initialize CompareStrings constraintAnnotation            this propertyNames   constraintAnnotation propertyNames            this comparisonMode   constraintAnnotation matchMode            this allowNull   constraintAnnotation allowNull                Override     public boolean isValid Object target  ConstraintValidatorContext context            boolean isValid   true          List lt String gt  propertyValues   new ArrayList lt String gt   propertyNames length           for int i 0  i lt propertyNames length  i                  String propertyValue   ConstraintValidatorHelper getPropertyValue String class  propertyNames i   target               if propertyValue    null                    if  allowNull                        isValid   false                      break                                  else                   propertyValues add propertyValue                                    if isValid                isValid   ConstraintValidatorHelper isValid propertyValues  comparisonMode                      if   isValid                              if custom message was provided  don t touch it  otherwise build the              default message                         String message   context getDefaultConstraintMessageTemplate              message    message isEmpty       ConstraintValidatorHelper resolveMessage propertyNames  comparisonMode    message             context disableDefaultConstraintViolation              ConstraintViolationBuilder violationBuilder   context buildConstraintViolationWithTemplate message             for  String propertyName   propertyNames                NodeBuilderDefinedContext nbdc   violationBuilder addNode propertyName               nbdc addConstraintViolation                                       return isValid            ConstraintValidatorHelper   public abstract class ConstraintValidatorHelper    public static  lt T gt  T getPropertyValue Class lt T gt  requiredType  String propertyName  Object instance            if requiredType    null                throw new IllegalArgumentException  Invalid argument  requiredType must NOT be null                       if propertyName    null                throw new IllegalArgumentException  Invalid argument  PropertyName must NOT be null                       if instance    null                throw new IllegalArgumentException  Invalid argument  Object instance must NOT be null                       T returnValue   null          try               PropertyDescriptor descriptor   new PropertyDescriptor propertyName  instance getClass                 Method readMethod   descriptor getReadMethod                if readMethod    null                    throw new IllegalStateException  Property      propertyName      of     instance getClass   getName       is NOT readable                               if requiredType isAssignableFrom readMethod getReturnType                       try                       Object propertyValue   readMethod invoke instance                       returnValue   requiredType cast propertyValue                     catch  Exception e                        e printStackTrace       unable to invoke readMethod                                           catch  IntrospectionException e                throw new IllegalArgumentException  Property      propertyName      is NOT defined in     instance getClass   getName          e                     return returnValue              public static boolean isValid Collection lt String gt  propertyValues  StringComparisonMode comparisonMode            boolean ignoreCase   false          switch  comparisonMode            case EQUAL IGNORE CASE          case NOT EQUAL IGNORE CASE              ignoreCase   true                     List lt String gt  values   new ArrayList lt String gt   propertyValues size             for String propertyValue   propertyValues                if ignoreCase                    values add propertyValue toLowerCase                   else                   values add propertyValue                                    switch  comparisonMode            case EQUAL          case EQUAL IGNORE CASE              Set lt String gt  uniqueValues   new HashSet lt String gt   values               return uniqueValues size      1   true   false          case NOT EQUAL          case NOT EQUAL IGNORE CASE              Set lt String gt  allValues   new HashSet lt String gt   values               return allValues size      values size     true   false                     return true             public static String resolveMessage String   propertyNames  StringComparisonMode comparisonMode            StringBuffer buffer   concatPropertyNames propertyNames           buffer append   must            switch comparisonMode            case EQUAL          case EQUAL IGNORE CASE              buffer append   be equal                break          case NOT EQUAL          case NOT EQUAL IGNORE CASE              buffer append   not be equal                break                    buffer append               return buffer toString               private static StringBuffer concatPropertyNames String   propertyNames              TODO improve concating algorithm         StringBuffer buffer   new StringBuffer            buffer append               for String propertyName   propertyNames                char firstChar   Character toUpperCase propertyName charAt 0                buffer append firstChar               buffer append propertyName substring 1                buffer append                          buffer delete buffer length  -2  buffer length             buffer append               return buffer            User   CompareStrings propertyNames   password    confirmPassword    public class User       private String password      private String confirmPassword       public String getPassword     return password        public void setPassword String password    this password   password        public String getConfirmPassword     return confirmPassword        public void setConfirmPassword String confirmPassword    this confirmPassword    confirmPassword        Test      public void test             User user   new User            user setPassword  password            user setConfirmPassword  paSSword            Set lt ConstraintViolation lt User gt  gt  violations   beanValidator validate user           for ConstraintViolation lt User gt  violation   violations                logger debug  Message -     violation getMessage                       Assert assertEquals violations size    1           Output Message -  Password  ConfirmPassword  must be equal   By using the CompareStrings validation constraint  we can also compare more than two properties and we can mix any of four string comparison methods   ColorChoice   CompareStrings propertyNames   color1    color2    color3    matchMode StringComparisonMode NOT EQUAL  message  Please choose three different colors    public class ColorChoice        private String color1      private String color2      private String color3                     Test  ColorChoice colorChoice   new ColorChoice            colorChoice setColor1  black            colorChoice setColor2  white            colorChoice setColor3  white            Set lt ConstraintViolation lt ColorChoice gt  gt  colorChoiceviolations   beanValidator validate colorChoice           for ConstraintViolation lt ColorChoice gt  violation   colorChoiceviolations                logger debug  Message -     violation getMessage                 Output Message - Please choose three different colors   Similarly  we can have CompareNumbers  CompareDates  etc cross-fields validation constraints   P S  I have not tested this code under production environment  though I tested it under dev environment   so consider this code as Milestone Release  If you find a bug  please write a nice comment

User · Answer

I suggest you another possible solution  Perhaps less elegant  but easier   public class MyBean      Size min 6  max 50    private String pass     private String passVerify      AssertTrue message  passVerify field should be equal than pass field     private boolean isValid         return this pass equals this passVerify           The isValid method is invoked by the validator automatically

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Why not try Oval  http   oval sourceforge net   I looks like it supports OGNL so maybe you could do it by a more natural    Assert expr     value    this pass

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I m surprised this isn t available out of the box  Anyway  here is a possible solution   I ve created a class level validator  not the field level as described in the original question   Here is the annotation code     package com moa podium util constraints   import static java lang annotation ElementType    import static java lang annotation RetentionPolicy     import java lang annotation Documented  import java lang annotation Retention  import java lang annotation Target   import javax validation Constraint  import javax validation Payload    Target  TYPE  ANNOTATION TYPE    Retention RUNTIME   Constraint validatedBy   MatchesValidator class   Documented public  interface Matches      String message   default   com moa podium util constraints matches       Class lt   gt    groups   default        Class lt   extends Payload gt    payload   default        String field       String verifyField        And the validator itself   package com moa podium util constraints   import org mvel2 MVEL   import javax validation ConstraintValidator  import javax validation ConstraintValidatorContext   public class MatchesValidator implements ConstraintValidator lt Matches  Object gt       private String field    private String verifyField      public void initialize Matches constraintAnnotation        this field   constraintAnnotation field        this verifyField   constraintAnnotation verifyField           public boolean isValid Object value  ConstraintValidatorContext context        Object fieldObj   MVEL getProperty field  value       Object verifyFieldObj   MVEL getProperty verifyField  value        boolean neitherSet    fieldObj    null   amp  amp   verifyFieldObj    null        if  neitherSet          return true             boolean matches    fieldObj    null   amp  amp  fieldObj equals verifyFieldObj        if   matches          context disableDefaultConstraintViolation          context buildConstraintViolationWithTemplate  message              addNode verifyField             addConstraintViolation               return matches          Note that I ve used MVEL to inspect the properties of the object being validated  This could be replaced with the standard reflection APIs or if it is a specific class you are validating  the accessor methods themselves   The  Matches annotation can then be used used on a bean as follows    Matches field  pass   verifyField  passRepeat   public class AccountCreateForm       Size min 6  max 50    private String pass    private String passRepeat             As a disclaimer  I wrote this in the last 5 minutes  so I probably haven t ironed out all the bugs yet  I ll update the answer if anything goes wrong

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With Hibernate Validator 4 1 0 Final I recommend using  ScriptAssert  Exceprt from its JavaDoc      Script expressions can be written in any scripting or expression   language  for which a JSR 223   Scripting for the JavaTM Platform     compatible engine can be found on the classpath    Note  the evaluation is being performed by a scripting  engine  running in the Java VM  therefore on Java  server side   not on  client side  as stated in some comments   Example      ScriptAssert lang    javascript   script     this passVerify equals  this pass    public class MyBean      Size min 6  max 50    private String pass     private String passVerify      or with shorter alias and null-safe      ScriptAssert lang    javascript   alias            script      passVerify    null  amp  amp    passVerify equals   pass    public class MyBean      Size min 6  max 50    private String pass     private String passVerify      or with Java 7  null-safe Objects equals        ScriptAssert lang    javascript   script    Objects equals  this passVerify   this pass    public class MyBean      Size min 6  max 50    private String pass     private String passVerify      Nevertheless  there is nothing wrong with a custom class level validator  Matches solution

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Solution realated with question  How to access a field which is described in annotation property   Target ElementType FIELD   Retention RetentionPolicy RUNTIME   Documented public  interface Match        String field         String message   default            Target ElementType TYPE   Retention RetentionPolicy RUNTIME   Constraint validatedBy   MatchValidator class   Documented public  interface EnableMatchConstraint        String message   default  Fields must match         Class lt   gt    groups   default          Class lt   extends Payload gt    payload   default           public class MatchValidator implements  ConstraintValidator lt EnableMatchConstraint  Object gt          Override     public void initialize final EnableMatchConstraint constraint           Override     public boolean isValid final Object o  final ConstraintValidatorContext context            boolean result   true          try               String mainField  secondField  message              Object firstObj  secondObj               final Class lt   gt  clazz   o getClass                final Field   fields   clazz getDeclaredFields                 for  Field field   fields                    if  field isAnnotationPresent Match class                         mainField   field getName                        secondField   field getAnnotation Match class  field                        message   field getAnnotation Match class  message                         if  message    null       equals message                           message    Fields     mainField     and     secondField     must match                         firstObj   BeanUtils getProperty o  mainField                       secondObj   BeanUtils getProperty o  secondField                        result   firstObj    null  amp  amp  secondObj    null    firstObj    null  amp  amp  firstObj equals secondObj                       if   result                            context disableDefaultConstraintViolation                            context buildConstraintViolationWithTemplate message  addPropertyNode mainField  addConstraintViolation                            break                                                                  catch  final Exception e                   ignore               e printStackTrace                      return result            And how to use it     Like this    Entity  EnableMatchConstraint public class User         NotBlank     private String password        Match field    password       private String passwordConfirmation

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You need to call it explicitly  In the example above  bradhouse has given you all the steps to write a custom constraint   Add this code in your caller class   ValidatorFactory factory   Validation buildDefaultValidatorFactory    validator   factory getValidator     Set lt ConstraintViolation lt yourObjectClass gt  gt  constraintViolations   validator validate yourObject     in the above case it would be   Set lt ConstraintViolation lt AccountCreateForm gt  gt  constraintViolations   validator validate objAccountCreateForm

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Each field constraint should be handled by a distinct validator annotation  or in other words it s not suggested practice to have one field s validation annotation checking against other fields  cross-field validation should be done at the class level  Additionally  the JSR-303 Section 2 2 preferred way to express multiple validations of the same type is via a list of annotations  This allows the error message to be specified per match   For example  validating a common form      FieldMatch List            FieldMatch first    password   second    confirmPassword   message    The password fields must match             FieldMatch first    email   second    confirmEmail   message    The email fields must match      public class UserRegistrationForm         NotNull      Size min 8  max 25      private String password        NotNull      Size min 8  max 25      private String confirmPassword        NotNull      Email     private String email        NotNull      Email     private String confirmEmail      The Annotation   package constraints   import constraints impl FieldMatchValidator   import javax validation Constraint  import javax validation Payload  import java lang annotation Documented  import static java lang annotation ElementType ANNOTATION TYPE  import static java lang annotation ElementType TYPE  import java lang annotation Retention  import static java lang annotation RetentionPolicy RUNTIME  import java lang annotation Target          Validation annotation to validate that 2 fields have the same value     An array of fields and their matching confirmation fields can be supplied        Example  compare 1 pair of fields      FieldMatch first    password   second    confirmPassword   message    The password fields must match          Example  compare more than 1 pair of fields      FieldMatch List         FieldMatch first    password   second    confirmPassword   message    The password fields must match          FieldMatch first    email   second    confirmEmail   message    The email fields must match          Target  TYPE  ANNOTATION TYPE    Retention RUNTIME   Constraint validatedBy   FieldMatchValidator class   Documented public  interface FieldMatch       String message   default   constraints fieldmatch         Class lt   gt    groups   default          Class lt   extends Payload gt    payload   default                      return The first field             String first                     return The second field             String second                    Defines several  lt code gt  FieldMatch lt  code gt  annotations on the same element                see FieldMatch              Target  TYPE  ANNOTATION TYPE        Retention RUNTIME       Documented              interface List               FieldMatch   value              The Validator   package constraints impl   import constraints FieldMatch  import org apache commons beanutils BeanUtils   import javax validation ConstraintValidator  import javax validation ConstraintValidatorContext   public class FieldMatchValidator implements ConstraintValidator lt FieldMatch  Object gt        private String firstFieldName      private String secondFieldName        Override     public void initialize final FieldMatch constraintAnnotation                firstFieldName   constraintAnnotation first            secondFieldName   constraintAnnotation second                Override     public boolean isValid final Object value  final ConstraintValidatorContext context                try                       final Object firstObj   BeanUtils getProperty value  firstFieldName               final Object secondObj   BeanUtils getProperty value  secondFieldName                return firstObj    null  amp  amp  secondObj    null    firstObj    null  amp  amp  firstObj equals secondObj                     catch  final Exception ignore                           ignore                   return true

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I made a small adaptation in Nicko s solution so that it is not necessary to use the Apache Commons BeanUtils library and replace it with the solution already available in spring  for those using it as I can be simpler   import org springframework beans BeanWrapper  import org springframework beans PropertyAccessorFactory   import javax validation ConstraintValidator  import javax validation ConstraintValidatorContext   public class FieldMatchValidator implements ConstraintValidator lt FieldMatch  Object gt         private String firstFieldName      private String secondFieldName        Override     public void initialize final FieldMatch constraintAnnotation            firstFieldName   constraintAnnotation first            secondFieldName   constraintAnnotation second                Override     public boolean isValid final Object object  final ConstraintValidatorContext context             BeanWrapper beanWrapper   PropertyAccessorFactory forBeanPropertyAccess object           final Object firstObj   beanWrapper getPropertyValue firstFieldName           final Object secondObj   beanWrapper getPropertyValue secondFieldName            boolean isValid   firstObj    null  amp  amp  secondObj    null    firstObj    null  amp  amp  firstObj equals secondObj            if   isValid                context disableDefaultConstraintViolation                context buildConstraintViolationWithTemplate context getDefaultConstraintMessageTemplate                     addPropertyNode firstFieldName                   addConstraintViolation                       return isValid

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I like the idea from Jakub Jirutka to use Spring Expression Language  If you don t want to add another library dependency  assuming that you already use Spring   here is a simplified implementation of his idea   The constraint    Constraint validatedBy ExpressionAssertValidator class   Target  ElementType TYPE    Retention RetentionPolicy RUNTIME  public  interface ExpressionAssert       String message   default  expression must evaluate to true       Class lt   gt    groups   default         Class lt   extends Payload gt    payload   default         String value        The validator   public class ExpressionAssertValidator implements ConstraintValidator lt ExpressionAssert  Object gt        private Expression exp       public void initialize ExpressionAssert annotation            ExpressionParser parser   new SpelExpressionParser            exp   parser parseExpression annotation value                public boolean isValid Object value  ConstraintValidatorContext context            return exp getValue value  Boolean class             Apply like this    ExpressionAssert value  pass    passVerify   message  passwords must be same   public class MyBean        Size min 6  max 50      private String pass      private String passVerify

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Very nice solution bradhouse   Is there any way to apply the  Matches annotation to more than one field   EDIT  Here s the solution I came up with to answer this question  I modified the Constraint to accept an array instead of a single value      Matches fields   password    email    verifyFields   confirmPassword    confirmEmail    public class UserRegistrationForm          NotNull      Size min 8  max 25      private String password        NotNull      Size min 8  max 25      private String confirmPassword         NotNull      Email     private String email        NotNull      Email     private String confirmEmail      The code for the annotation   package springapp util constraints   import static java lang annotation ElementType    import static java lang annotation RetentionPolicy     import java lang annotation Documented  import java lang annotation Retention  import java lang annotation Target   import javax validation Constraint  import javax validation Payload    Target  TYPE  ANNOTATION TYPE    Retention RUNTIME   Constraint validatedBy   MatchesValidator class   Documented public  interface Matches      String message   default   springapp util constraints matches       Class lt   gt    groups   default        Class lt   extends Payload gt    payload   default        String   fields       String   verifyFields        And the implementation   package springapp util constraints   import javax validation ConstraintValidator  import javax validation ConstraintValidatorContext   import org apache commons beanutils BeanUtils   public class MatchesValidator implements ConstraintValidator lt Matches  Object gt         private String   fields      private String   verifyFields       public void initialize Matches constraintAnnotation            fields   constraintAnnotation fields            verifyFields   constraintAnnotation verifyFields               public boolean isValid Object value  ConstraintValidatorContext context             boolean matches   true           for  int i 0  i lt fields length  i                  Object fieldObj  verifyFieldObj              try                   fieldObj   BeanUtils getProperty value  fields i                    verifyFieldObj   BeanUtils getProperty value  verifyFields i                  catch  Exception e                      ignore                 continue                            boolean neitherSet    fieldObj    null   amp  amp   verifyFieldObj    null               if  neitherSet                    continue                             boolean tempMatches    fieldObj    null   amp  amp  fieldObj equals verifyFieldObj                if   tempMatches                    addConstraintViolation context  fields i     fields do not match   verifyFields i                               matches   matches tempMatches matches                    return matches             private void addConstraintViolation ConstraintValidatorContext context  String message  String field            context disableDefaultConstraintViolation            context buildConstraintViolationWithTemplate message  addNode field  addConstraintViolation

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You guys are awesome  Really amazing ideas  I like Alberthoven s and McGin s most  so I decided to combine both ideas  And develop some generic solution to cater all cases  Here is my proposed solution    Documented  Constraint validatedBy   NotFalseValidator class   Target  ElementType METHOD  ElementType FIELD ElementType TYPE    Retention RetentionPolicy RUNTIME  public  interface NotFalse         String message   default  NotFalse       String   messages        String   properties        String   verifiers         Class lt   gt    groups   default          Class lt   extends Payload gt    payload   default            public class NotFalseValidator implements ConstraintValidator lt NotFalse  Object gt        private String   properties      private String   messages      private String   verifiers       Override     public void initialize NotFalse flag            properties   flag properties            messages   flag messages            verifiers   flag verifiers                Override     public boolean isValid Object bean  ConstraintValidatorContext cxt            if bean    null                return true                     boolean valid   true          BeanWrapper beanWrapper   PropertyAccessorFactory forBeanPropertyAccess bean            for int i   0  i lt  properties length  i                 Boolean verified    Boolean  beanWrapper getPropertyValue verifiers i               valid  amp   isValidProperty verified messages i  properties i  cxt                      return valid             boolean isValidProperty Boolean flag String message  String property  ConstraintValidatorContext cxt            if flag    null    flag                return true            else               cxt disableDefaultConstraintViolation                cxt buildConstraintViolationWithTemplate message                       addPropertyNode property                       addConstraintViolation                return false                             NotFalse          messages     End Date Before Start Date     Start Date Before End Date              properties   endDateTime     startDateTime            verifiers     validDateRange     validDateRange    public class SyncSessionDTO implements ControllableNode        NotEmpty  NotPastDate     private Date startDateTime        NotEmpty     private Date endDateTime         public Date getStartDateTime             return startDateTime             public void setStartDateTime Date startDateTime            this startDateTime   startDateTime             public Date getEndDateTime             return endDateTime             public void setEndDateTime Date endDateTime            this endDateTime   endDateTime              public Boolean getValidDateRange            if startDateTime    null  amp  amp  endDateTime    null                return startDateTime getTime    lt   endDateTime getTime                       return null

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I don t have the reputation for commenting on the first answer but wanted to add that I have added unit tests for the winning answer and have the following observations   If you get the first or field names wrong then you get a validation error as though the values don t match  Don t get tripped up by spelling mistakes e g     FieldMatch first  quot invalidFieldName1 quot   second  quot validFieldName2 quot     The validator will accept equivalent data types i e  these will all pass with FieldMatch    private String stringField    quot 1 quot   private Integer integerField   new Integer 1  private int intField   1    If the fields are of an object type which does not implement equals  the validation will fail

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I have tried Alberthoven s example  hibernate-validator 4 0 2 GA  and i get an ValidationException     Annotated methods must follow the JavaBeans naming convention  match   does not     too  After I renamed the method from    match    to  isValid  it works     public class Password        private String password       private String retypedPassword       public Password String password  String retypedPassword            super            this password   password          this retypedPassword   retypedPassword              AssertTrue message  password should match retyped password       private boolean isValid            if  password    null                return retypedPassword    null            else               return password equals retypedPassword                        public String getPassword             return password             public String getRetypedPassword             return retypedPassword

[validation] Cross field validation with Hibernate Validator (JSR 303)

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