1. Long story short
2. About ReMap
3. News
4. Mapping operations
5. Validation
6. Features
7. Limitations
8. The mapping cookbook
   1. Implicit Mappings
   2. Mapping fields of the same type
   3. Mapping fields using another mapper
   4. Mapping fields with different names using another mapper
   5. Conversion of collections
   6. Mapping fields with a custom mapping function
   7. Transforming collections with a custom mapping function
   8. Type mappings
   9. Mapping with property paths
   10. Mapping other values to a field
   11. Restructure a complex object in the destination
   12. Mapping maps
   13. Tests
9. Mapping meta model
10. Spring integration
11. Spring Boot Issue
12. Migration guide
13. How to contribute

ReMap is a library that simplifies conversion of objects field by field and greatly reduces the efforts for unit testing mapper classes. You can get this library via Maven Central using the following coordinates

ReMap is available through and JCenter

The following code snippet shows how to map a source type to a destination type:

Mapping.from(Customer.class)
    .to(Person.class)
    .omitInSource(Customer::getAddress)
    .omitInDestination(Person::getBodyHeight)
    .reassign(Customer::getTitle)
        .to(Person::getSalutation)
    .replace(Customer::getGender, Person::getGender)
        .withSkipWhenNull(Gender::valueOf)
    .mapper();

The resulting mapper does the following:

• maps Customer objects to Person objects
• Customer has the field address, Person does not, hence it is omitted
• Person has the field bodyHeight and Customer does not, hence it is omitted
• the field Customer.title is mapped to the field Person.salutation
• the field Customer.gender of type String is mapped to the Field Customer.gender of enum type Gender using Gender.valueOf() as a transformation function

You can find this demo and the involved classes here

ReMap is a library that simplifies conversion of objects field by field. It was developed to make conversion of database entities to DTOs (data transfer objects) easier. The use of ReMap makes converter classes and unit tests for converters obsolete: ReMap only needs a specification of what fields are to be mapped, but the amount of code that actually performs the assignments and transformations is minimized. Therefore the code that must be unit-tested is also minimized.

ReMap maps a objects of a source to a destination type. As per default ReMap tries to map all fields from the source to the destination object if the fields have equal name and equal types or equal name and a mapper was registered to perform the type mapping. Only differences between the source type and the target type must be specified when creating a mapper.

The map-into feature of ReMap is now deprecated. This function was never correctly implemented and does not work recursively.

Due to complexity we will remove the following features from the API in a future release:

• com.remondis.remap.Mapper.map(S source, D dest)
• com.remondis.remap.MappingConfiguration.writeNullIfSourceIsNull()
• any dependencies of the assert API to this methods

Please make sure, that your mappings do not rely on this features.

Thanks to @djarnis73 ReMap now supports fluent-style setters. This relaxes the Java Bean convention in a way, that bean setter methods are now allowed to have a return type different from void

How to use:

Mapper<FluentSetterDto, FluentSetterDto> m = Mapping.from(FluentSetterDto.class)
        .to(FluentSetterDto.class)
        .allowFluentSetters()
        .mapper();
FluentSetterDto expected = new FluentSetterDto().setInteger(5)
        .setI(22)
        .setS("str")
        .setB1(true)
        .setB2(true);
FluentSetterDto actual = m.map(expected);

This example is taken from here

Note: To add this feature in a backwards compatible way, you have to activate it using .allowFluentSetters().

Since version 4.1.16 ReMap supports the mapping of maps as well as mapping of generic nesting of collections/maps as long as the collection types (collection or map) match on source and destination fields.

See Conversion of collections for more information.

You can call Mapper.toString() to get an overview of what the mapper does. Since the first version of ReMap the mapping configuration can be visualized this way but only a few people now that.

The mapper from the example above would produce the following toString() output:

Mapping from com.remondis.remap.demo.Customer
	  to com.remondis.remap.demo.Person
 with transformation:
- Omitting Property 'bodyHeight' in com.remondis.remap.demo.Person
- Map Property 'name' in com.remondis.remap.demo.Customer
   to Property 'name' in com.remondis.remap.demo.Person
- Omitting Property 'address' in com.remondis.remap.demo.Customer
- Replacing but skipping when null Property 'gender' in com.remondis.remap.demo.Customer
           with Property 'gender' in com.remondis.remap.demo.Person using transformation
- Map Property 'forname' in com.remondis.remap.demo.Customer
   to Property 'forname' in com.remondis.remap.demo.Person
- Reassigning Property 'title' in com.remondis.remap.demo.Customer
           to Property 'salutation' in com.remondis.remap.demo.Person
All properties are mapped!

This may give you a better overview when trying to understand especially older mapping configurations.

The following operations can be declared on a mapper:

• omitInSource: omits a field in the source type and skips the mapping.
• omitInDestination: omits a field in the destination type and skips the mapping.
• omitOtherSourceProperties: omits all source fields that are not configured differently.
• omitOtherDestinationProperties: omits all source fields that are not configured differently.
• omitOthers: omits all source and destination fields that are not configured differently.
• reassign: maps a source field to the destination field
  • if the property types are equal, references are copied
  • if the property types differ, a mapper must be registered that supports the type mapping
• replace: converts a source field to the destination field while changing the field name and the type. To transform the source object into the destination type a transformation function is to be specified.
• replaceCollection: converts a source collection to the destination collection by applying a transform function elementwise.
• set: Sets a value provided either by a function or by a value supplier in the destination.
• useMapper:
  • registers a specific mapper instance that is used to convert referenced Java Bean types.
  • registers a type mapping that is used to convert non-Java Bean types.

ReMap validates the mapping configuration of a mapper at instantiation time and denies the following states:

• A source field was not mapped to a destination field
• A destination field is not covered by a source field
• Multiple mappings where defined for a destination field
• omit is specified for a source field that already has a mapping configuration

These validation rules make sure that all fields are covered by the mapping configuration when a mapper instance is created.

Since ReMap relies on getter and setter references like Address::getId to specify a mapping, the compiler does not allow mappings between fields that are incompatible. When a mapper is instantiated, ReMap performs the above-mentioned validations.

Thus, the only things you need to test in a unit test are:

• that Mapping.mapper() does not throw a MappingException telling you that one of the validations failed
• any transformation functions specified for replace operations

Optionally, you may want to assert that your specification matches certain expectations to prevent regressions to creep into your codebase (see Tests).

ReMap supports

• out-of-the-box mapping of primitives, built-in types, custom Java Beans and enumeration values
• type inheritance
• fields holding non-Java Bean types can be mapped using a specific type mapping.
• mapping object references to fields
• mapping from interface to Java Bean type
• mapping of nested collections
• mapping of nested maps
• unit testing of mapping specifications
• mapping without invasively changing code of involved objects
• overwrite fields in an instance by specifying the target instance for the mapping
• mapping of fluent-style setters (setters having a return type)

• objects that should be mapped must meet the Java Bean convention
  • fields can have any visibility
  • fields have properly named public get/set methods
    • getter methods are mandatory for source and destination properties
    • setter methods are only mandatory for destination properties
  • fields of primitive type boolean comply with is-method convention as getter.
  • the declaring type has a public default constructor (this is only necessary for the destination object)
  • keywords like transient do not have an effect on the mapping
• non-static inner classes are not supported (they do not have a parameterless default constructor!)
• circular references are currently not supported
• mapping equal types does not copy object instances!
• multi-classloader environments are currently not supported. All types must be loaded by the same classloader.
• Generics cannot be used without limitations: It is possible to build a mapper for generic types, but due to the class literals used when declaring the mapping, the generic type informations gets lost.

The short mapping shown under Long story short shows only a few mapping features of ReMap. The following examples try to cover up the basics of ReMap but also provides code snippets that may help if your mapping becomes a little more complex.

ReMap performs implicit mappings if

• property name and type of source and destination fields are equal
• property name of source and destination field are equal and mappers were registered that can perform the necessary type conversion (explained later).

Assuming A and B have the exact same number of properties with the same names and types, the following mapping configuration is enough to map all fields automatically.

This also works for collections!

Mapper<A, B> mapper = Mapping
    .from(A.class)
    .to(B.class)
    .mapper();

Sometimes fields have the same type but different names. In this case ReMap will not create implicit mappings. In this case use a reassign operation.

This also works for collections and maps!

The following example shows how to map properties with the same type but differing field names.

public class A {
String name;
// default constructor, getter/setter, ...
}

public class B {
String lastName;
// default constructor, getter/setter, ...
}

Mapper<A, B> mapper = Mapping
    .from(A.class)
    .to(B.class)
    .reassign(A::getName)
    .to(AResource::getLastName)
    .mapper();

ReMap supports the reuse of mappers. If you want to map fields for whose type conversions a mapper was already defined, you can register the mapper in the mapping configuration and use it.

This also works for collections and maps!

public class A {
SomeBean someBean;
// default constructor, getter/setter, ...
}

public class B {
AnotherBean someBean;
// default constructor, getter/setter, ...
}

Mapper<SomeBean, AnotherBean> someBeanToAnotherBean = Mapping
    .from(SomeBean.class)
    .to(AnotherBean.class)
    // ...
    .mapper();

Mapper<A, B> mapper = Mapping
    .from(A.class)
    .to(B.class)
    .useMapper(someBeanToAnotherBean)
    .mapper();

As you can see, the mapping of the fields with name someBean are performed automatically because the mapper supporting the required type conversion was registered.

If the field names differ you can simply use a reassign operation to specify the new field name!

Assuming the field names differ but you want to map fields for whose type conversions a mapper was already defined, you can register the mapper in the mapping configuration and use it in conjunction with a reassign operation.

This also works for collections and maps!

public class A {
SomeBean someBean;
// default constructor, getter/setter, ...
}

public class B {
AnotherBean anotherBean;
// default constructor, getter/setter, ...
}

Mapper<SomeBean, AnotherBean> someBeanToAnotherBean = Mapping
    .from(SomeBean.class)
    .to(AnotherBean.class)
    // ...
    .mapper();

Mapper<A, B> mapper = Mapping
    .from(A.class)
    .to(B.class)
    .useMapper(someBeanToAnotherBean)
    .reassign(A::getSomeBean)
    .to(B::getAnotherBean)
    .mapper();

As you can see, you only have to configure the different field names. The type conversion is performed automatically because the required mapper was registered.

ReMap supports the mapping of collection types. If the types (collection or map) match for source and destination field on each level of nesting, the conversion of the collection is performed automatically.

Example:

A Java Bean with the following field

public class A {
  private List<Set<B>> nestedLists;
}

can be mapped automatically to

public class AResource {
  private Set<List<BResource>> nestedLists;
}

ReMap converts the java.util.List to a java.util.Set vice-versa. But note this operation removes duplicates due to the behaviour of Set.

This also works in conjunction with java.util.Map on any generic nesting level.

Note: ReMap only converts matching collection types. The conversion from List to Map is not supported.

Sometimes you want to perform the mapping of fields with a custom function. ReMap supports custom mapping functions with the replace operation. This operation takes two fields and performs the mapping by applying a specified function on the source field value. The result is then used as the destination field value.

The replace operation allows two configurations:

• with(Function): applies the function, even if the source field is null. As a consequence the function must implement null-checks to be null-safe.
• withSkipWhenNull(Function): only applies the function if the source field is not null. If the source field is null this field will not be mapped.

public class A {
String name;
// default constructor, getter/setter, ...
}

public class B {
int nameLength;
// default constructor, getter/setter, ...
}

Mapper<A, B> mapper = Mapping
    .from(A.class)
    .to(B.class)
    .replace(A::getName, B::getNameLength)
    .withSkipWhenNull(String::length)
    .to(AResource::getLastName)
    .mapper();

The above example maps the name property in A to the nameLength property in B by converting the string to the length using a transformation function. Note: The example shows a transformation function that is only called if A.name has a value. If the property is null the mapping is skipped.

When a mapping of collection items should be performed you can use the operation replaceCollection to apply the transformation function automatically on the collection items.

The following code snippet shows how to use replaceCollection:

Mapper<Source, Destination> mapper = Mapping.from(Source.class)
      .to(Destination.class)
      .replaceCollection(Source::getIds, Destination::getIds)
      .with(id -> Id.builder()
        .id(id)
        .build())
      .mapper();

In this example the mapping is performed from List<String> to List<Id> but with replaceCollection you only have to define a mapping function with type String -> Id.

You can find this demo and the involved classes here

When mapping types that are not Java Beans you can either use the replace operation or you can use a type mapping. Type mappings are like the functions used for replace but they can be globally registered on the mapper. Type mappings act like registered mappers (see useMapper()): They are applied when a type conversion is required for an implicit mapping or a reassign mapping.

Type mappings may reduce the number of replace operations in your mapping configuration if the type mapping occurs very often, because the type conversion can be registered globally.

The following example shows the use of type mappings:

public class Person {
  private CharSequence forname;
  private CharSequence lastName;
  private List<CharSequence> addresses;
  // Getters/Setters...
}

public class Customer {
  private String forname;
  private String lastName;
  private List<String> addresses;
  // Getters/Setters...
}

Mapping.from(Person.class)
        .to(Customer.class)
        .useMapper(
             TypeMapping.from(CharSequence.class)
                        .to(String.class)
                        .applying(String::valueOf))
        .mapper();

In this example the mapping from CharSequence to String is defined globally for the mapping. In implicit mappings (field names are equal) or reassing operations the global mapping function defined by the type mapping is used to perform the conversion.

ReMap can be used to flatten object hierarchies. You can perform a mapping by specifying a get-call chain on the source type. If the get-call chain evaluates to a non-null value, the result is mapped to the destination field.

A property path is a special get-call chain: The actual get-method calls are performed by the framework. Each get-call is checked for a non-null return value. If a get returns a null value, the whole property path evaluates to no value and the mapping is skipped.

public class Contract {
  private Company company; // Optional, may be null
  // Getters, Setters, No-Args Default Constructor...
}

public class Company {
  private List<Address> addresses; // Optional, may be null or empty
  // Getters, Setters, No-Args Default Constructor...
}

public class Address {
  String city; // Desired value to get.
  // Getters, Setters, No-Args Default Constructor...
}

public class City {
String city;
// default constructor, getter/setter, ...
}

Mapper<Contract, City> mapper = Mapping
    .from(Contract.class)
    .to(City.class)
    .replace(Contract::getCompany, City::getCity)
    .withPropertyPath(company -> company.getAddresses()
        .get(0)
        .getCity())
    .mapper();

The above example maps the city property from a complex object hierarchy to the destination field City.city.

Keep in mind that if Contract::getCompany returns null or any other get-call in company.getAddresses().get(0).getCity(), the mapping is skipped.

When declaring a property path the following calls are supported:

• any Java Bean property conform getter
• java.util.List.get(int)
• java.util.Map.get(Object)

It is also possible to apply a transformation function to the result of a property path evaluation. The following mapping reduces the city from the above example to the string length by applying a transformation function:

Mapper<Contract, City> mapper = Mapping
    .from(Contract.class)
    .to(City.class)
    .replace(Contract::getCompany, City::getCityLength)
    .withPropertyPathAnd(company -> company.getAddresses()
        .get(0)
        .getCity())
    .apply(String::length)
    .mapper();

The above example assumes, that the field City.cityLength of type int exists.

Sometimes you want to specify another source of a value that is to be mapped to a destination field, rather than using the source field of the source mapping type. In this case you can use the set operation:

public class A {
String name;
// default constructor, getter/setter, ...
}

public class B {
String name;
int age;
// default constructor, getter/setter, ...
}

Mapper<A, B> mapper = Mapping
    .from(A.class)
    .to(B.class)
    .set(B::getAge)
    .with(24)
    .mapper();

Assume you don't have a source field to map to B.age. In this case the set operation specifies the static value 24 that is used during the mapping.

The value for the mapping can be provided by either a static value, a java.util.function.Supplier or a java.util.function.Function.

When using the set operation, you can specify a function that produces the value to be set on the destination field.

The function gets the reference to the source object and returns a value used for the destination field. This mapping is useful if you need full access to the source object for your custom mapping function.

Do not mix up the set- and replace-operations: Sometimes you can write a replace- as a set-operation. As a result you often have to perform a get-call yourself instead of having ReMap handling the get-call and the optional null-checks. Don't use set, if you can use replace.

Consider you have a flat data structure and you want to map this to a more structured complex object. An example for a flat person structure is the following:

public class PersonFlat {
    private String forename;
    private String name;

    private String street;
    private String houseNumber;

    // Constructors, getter/setter...
}

You can use the restructure operation to define mappings that build complex objects from the fields of PersonFlat. We want to map the PersonFlat into the following object hierarchy:

public class Family {
    private Person dad;
}

public class Person {
    private String forename;
    private String name;
    private Address address;
}

public class Address {
    private String street;
    private String houseNumber;
}

In the past you might have use a set operation using a function to create all these objects to achieve this. Since ReMap 4.2.2 you can use mappers for this:

    Mapper<PersonFlat, Family> mapper = Mapping.from(PersonFlat.class)
        .to(Family.class)
        .omitOtherSourceProperties()
        .restructure(Family::getDad) // Build a Person instance out of PersonFlat
        .applying(flat2PersonMapping -> flat2PersonMapping.restructure(Person::getAddress) // Build an Address instance out of PersonFlat.
            .implicitly())
        .mapper();

As you can see, you can tell the mapper to restructure the field Dad which is a Person. After defining the restructure operation on the mapper PersonFlat to Family we can specify a mapping configuration for the mapping PersonFlat to Person using applying(...). Due to the fact that the mapper does not create restructure-mappings explicitly, we have to apply a mapping configuration telling the mapper to restructure the field address in Person. Since this is a mapping from PersonFlat to Address the mapping of the fields street and houseNumber can be performed implicitly.

Of course you can test your mapping with the Assertion API of ReMap. For a more detailed example see RestructuringDemoTest

Note: The restructure operation creates an omitOtherSourceProperties on the mapper. This was done because most of the time you do not need all source fields to restructure a destination object.

Since version 4.1.16 ReMap supports mapping of nested collections and maps. The generic type nesting of a source field is mapped to the desired type nesting declared by the destination field using type mappings and registered mappers.

Example:

public class A {
  private Map<List<A1>, Map<A2, A3>> map;
}

can be mapped automatically to

public class AMapped {
  private Map<List<A1Mapped>, Map<A2Mapped, A3Mapped>> map;
}

if the following mappers were registered on the mapping:

• A1 to A1Mapped
• A2 to A2Mapped
• A3 to A3Mapped

ReMap provides an easy way to assert the mapping specification for a mapper instance. These assertions should be used in unit tests to provide regression tests for your mapping configuration.

For every mapping operation ReMap supports, an assert can be specified. Since there are a lot of mapping features please have a look at the JavaDoc of com.remondis.remap.AssertMapping for a documentation and further explanations.

The following example shows how to assert some of the mapping features in a mapping specification:

Given the following mapping...

Mapper<B, BResource> bMapper = Mapping.from(B.class)
    .to(BResource.class)
    .mapper();

Mapper<A, AResource> mapper = Mapping.from(A.class)
    .to(AResource.class)
    .reassign(A::getString)
        .to(AResource::getAnotherString)
    .replace(A::getInteger, AResource::getIntegerAsString)
        .with(String::valueOf)
    .omitInSource(A::getOmitted)
    .omitInDestination(AResource::getOmitted)
    .useMapper(bMapper)
    .mapper();

...the following assertion can be made to ensure regression validity for the mapping specification:

AssertMapping.of(mapper)
    .expectReassign(A::getString)
        .to(AResource::getAnotherString)
    .expectReplace(A::getInteger, AResource::getIntegerAsString)
        .andTest(String::valueOf)
    .expectOmitInSource(A::getOmitted)
    .expectOmitInDestination(AResource::getOmitted)
    .ensure();

The asserts check that the expected mappings are also configured on the specified mapper. If there are differences, the ensure() method will throw an assertion error.

Note: The replace operation supports two null-strategies and the mapper needs to specify the same strategy as the asserts! The transformation function in this example is checked against a null when ensure() is invoked. If the replace operation was added using withSkipWhenNull() the specified transformation function is not checked against null.

ReMap provides a meta model that allows to search for top-level mappings. This can be used to perform single value mappings without the need of having an instance of the whole source object. The mapping model can be obtained by calling getMappingModel() on a valid mapper.

The meta model allows to search for field mappings. Since some search methods can return multiple results, the search results must be checked using com.remondis.remap.MappingModel.TransformationSearchResult.hasSingleResult() before performing transformations.

Note: The meta model distinguish between value and object mappings. Object mappings are set or restructure operations because the input for this mapping operations is the whole source object. So once a transformation was selected using the meta model, check the transformation type with com.remondis.remap.MappingModel.TransformationSearchResult.isObjectTransformation() or com.remondis.remap.MappingModel.TransformationSearchResult.isValueTransformation() to determine the input for performing this mapping operation.

ReMap can be nicely integrated in Spring Applications so that mapper instances can be injected using @Autowired. Spring also checks the generic type of the mapper to autowire the correct mapping requested.

The following bean configuration creates mappers to convert a Person into Human and vice versa:

@Configuration
static class TestConfiguration {
  @Bean
  Mapper<Person, Human> personHumanMapper(){
    return Mapping.from(Person.class)
        .to(Human.class)
        .mapper();
  }
  @Bean
  Mapper<Human, Person> humanPersonMapper(){
    return Mapping.from(Human.class)
        .to(Person.class)
        .mapper();
  }
}

Use the following code snippet in components to inject the mapper instances:

  @Autowired
  Mapper<Person, Human> mapper1;

  @Autowired
  Mapper<Human, Person> mapper2;

When using the Spring Boot Framework in version <= 1.5.13.RELEASE in combination with ReMap 4.0.0 a known issue can occur:

If you get the following exception...

        Caused by:
        java.lang.IllegalArgumentException
            at org.objectweb.asm.ClassVisitor.<init>(Unknown Source)
            at net.sf.cglib.core.DebuggingClassWriter.<init>(DebuggingClassWriter.java:49)
            at net.sf.cglib.core.DefaultGeneratorStrategy.getClassVisitor(DefaultGeneratorStrategy.java:30)
            at net.sf.cglib.core.DefaultGeneratorStrategy.generate(DefaultGeneratorStrategy.java:24)
            at net.sf.cglib.core.AbstractClassGenerator.generate(AbstractClassGenerator.java:329)
            at net.sf.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:93)
            at net.sf.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:91)
            at net.sf.cglib.core.internal.LoadingCache$2.call(LoadingCache.java:54)
            at java.util.concurrent.FutureTask.run(FutureTask.java:266)
            at net.sf.cglib.core.internal.LoadingCache.createEntry(LoadingCache.java:61)
            at net.sf.cglib.core.internal.LoadingCache.get(LoadingCache.java:34)
            at net.sf.cglib.core.AbstractClassGenerator$ClassLoaderData.get(AbstractClassGenerator.java:116)
            at net.sf.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:291)
            at net.sf.cglib.core.KeyFactory$Generator.create(KeyFactory.java:221)
            at net.sf.cglib.core.KeyFactory.create(KeyFactory.java:174)
            at net.sf.cglib.core.KeyFactory.create(KeyFactory.java:153)
            at net.sf.cglib.proxy.Enhancer.<clinit>(Enhancer.java:73)
            ... 1 more

...you can workaround this by adding the dependency compile "com.jayway.jsonpath:json-path:2.4.0" to your project. This error is caused by a library that ships classes of a dependency in an incompatible version.

The library net.minidev:accessors-smart:1.1 which is used as a transitive dependency requires org.ow2.asm:asm:5.0.3. ReMap declares org.ow2.asm in version 6.0 as dependecy so this newer version is chosen by dependency management of Maven or Gradle.

The problem is that this library does not only declare this dependency but ships it's own copy of the package org.objectweb.asm in this older version. Even if your dependecy management seems to choose org.ow2.asm:asm:6.0, the classes of 5.0.3 stay in the classpath.

+--- org.springframework.boot:spring-boot-starter-test:1.5.13.RELEASE
|    +--- com.jayway.jsonpath:json-path:2.2.
|    |    +--- net.minidev:json-smart:2.2.
|    |    |    \--- net.minidev:accessors-smart:1.
|    |    |         \--- org.ow2.asm:asm:5.0.3 -> 6.0 // Looks like 6.0 is chosen, but the classes of 5.0.3 stay in the classpath.

This bug was fixed in net.minidev:accessors-smart:1.2 but is still present in Spring Boot Framework in version <= 1.5.13.RELEASE. Since com.jayway.jsonpath:json-path:2.4.0 depends on this newer version it seems to be the safest way to overwrite the version of this library.

This workaround was tested and should work for most cases. Please file an issue if you are experiencing problems.

ReMap was extended to support fluent-style setter methods. Older versions of ReMap only support Java Bean compliant setter methods with return type void. Now fluent style setter methods are supported in a way, that a setter method might have a return type.

No migrations necessary - this feature is backwards compatible.

ReMap migrated to byte-buddy thanks to @Karlender. Since cglib is unmaintained ReMap would not be compatible to JDK17+. The migration is just an internal refactoring in ReMap - this sidenote is just about the dependency of ReMap to byte-buddy.

The static entrypoints for the ReMap API changed. Like in earlier versions, you can access the mapping and assertion API with Mapping.from(...) and AssertMapping.of(...) but if your code held references to instances of those types, you have to change the references to the type MappingConfiguration respectively AssertConfiguration.

The integration of the library propertypath (https://github.com/remondis-it/propertypath) was updated to version 0.1.0. This version introduced changes that are not backwards-compatible. If you update to ReMap 4.1.14 you will have to migrate to propertypath 0.1.0 as well - the changes are minimal ;)

Since the source property rules relaxed a little bit, no setter methods are required for the source type of the mapping. This was done to support mapping from read-only properties. This has one drawback: In earlier version read-only properties were not recognized as properties used for the mapping. This changed now and mappings that used an earlier version of ReMap in combination with read-only properties now need an omitInSource specification.

There were API changes that break backward compatibility:

• The method com.remondis.remap.ReplaceCollectionAssertBuilder.andTestButSkipWhenNull(Transform<RD, RS> transformation) changed to com.remondis.remap.ReplaceCollectionAssertBuilder.andSkipWhenNull(). Specifying transform function is not longer required. Please check your mapping assertions to match the new API.

There were API changes that break backward compatibility:

• The method com.remondis.remap.ReplaceAssertBuilder.andTestButSkipWhenNull(Transform<RD, RS> transformation) changed to com.remondis.remap.ReplaceAssertBuilder.andSkipWhenNull(). Specifying transform function is not longer required. Please check your mapping assertions to match the new API.
• The generic type in com.remondis.remap.Transform<D, S> changed to com.remondis.remap.Transform<S, D>
• According to the above change please check your mapping configuration and assertions for the replace operation to match the new API. The affected classes are:
  • com.remondis.remap.ReplaceBuilder
  • com.remondis.remap.ReplaceAssertBuilder
  • com.remondis.remap.ReplaceCollectionBuilder
  • com.remondis.remap.ReplaceCollectionAssertBuilder
  • com.remondis.remap.ReplaceTransformation
  • com.remondis.remap.Transformation

Please refer to the project's contribution guide