Package io.axoniq.dataprotection.api

Class ReplacementValueProvider

java.lang.Object

io.axoniq.dataprotection.api.ReplacementValueProvider

public class ReplacementValueProvider
extends Object

Class that represents the replacement value mechanism. It takes care of setting a value in the class when the decryption key is no longer there. The default behaviour of this class is very simple: for String fields, it will use the value of the replacement attribute in the PersonalData annotation, which is the empty String by default. In all other cases, it will be null. Applications may define more fine grained behaviour by creating their own subclass and providing this when constructing a FieldEncrypter or FieldEncryptingSerializer.

A method of this class is invoked when a key is missing upon decryption. However, we also see an invocation upon each encryption. This is to provide a partial, clear to be included in the storage. By default, nothing is stored. This allows functionality such as keeping the year of a full date even if the date itself gets deleted, or keeping the last 4 digits of a credit card number.

Constructor Summary

Constructors

Constructor	Description
ReplacementValueProvider()

Method Summary

Modifier and Type	Method	Description
byte[]	partialValueForStorage(Class<?> clazz, Field field, Type fieldType, String groupName, String replacement, Object inputValue)	Invoked as part of the encryption process.
Object	replacementValue(Class<?> clazz, Field field, Type fieldType, String groupName, String replacement, byte[] storedPartialValue)	Invoked when a field cannot be decrypted because the key is missing.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ReplacementValueProvider

public ReplacementValueProvider()

Method Detail

replacementValue

public Object replacementValue(Class<?> clazz,
                               Field field,
                               Type fieldType,
                               String groupName,
                               String replacement,
                               byte[] storedPartialValue)

Invoked when a field cannot be decrypted because the key is missing. The default implementation returns the value of replacement if fieldType equals String, and null otherwise (or the default value if fieldType represents a primitive).

Parameters:

clazz - the class of the object on which the field was found. This is not necessarily the same as field.getDeclaringClass(), since the field may be declared on a superclass of the class of our current object

field - the field we're decrypting

fieldType - the generic type of value that we need. This is not always the same as field.getGenericType(), since the module itself recurses into collections and arrays. So, if the field has type List<String>, then the fieldType will be String rather than List<String>.

groupName - the groupName from the PersonalData or SerializedPersonalData annotation

replacement - the replacement from the PersonalData or SerializedPersonalData annotation

storedPartialValue - the clear partial value previously stored with the encrypted value; may be null

Returns:

the object to be used as field value; may be null

partialValueForStorage

public byte[] partialValueForStorage(Class<?> clazz,
                                     Field field,
                                     Type fieldType,
                                     String groupName,
                                     String replacement,
                                     Object inputValue)

Invoked as part of the encryption process. Provides a partial, clear value in the form of a byte array to be stored with the encrypted value. The default implementation always returns null.

Parameters:

clazz - the class of the object on which the field was found. This is not necessarily the same as field.getDeclaringClass(), since the field may be declared on a superclass of the class of our current object

field - the field we're decrypting

fieldType - the generic type of value that we need. This is not always the same as field.getGenericType(), since the module itself recurses into collections and arrays. So, if the field has type List<String>, then the fieldType will be String rather than List<String>.

groupName - the groupName from the PersonalData or SerializedPersonalData annotation

replacement - the replacement from the PersonalData or SerializedPersonalData annotation

inputValue - the input value

Returns:

the byte array to be stored; may be null