Feature samples

Bean Utils Light Library

BULL is a Java Bean to Java Bean transformer that recursively copies data from one object to another, it is generic, flexible, reusable, configurable, and incredibly fast. It's the only library able to transform Mutable, Immutable, and Mixed bean without any custom configuration.

Start using

A tutorial that integrates the library can be found here.

All BULL modules are available on Maven Central:

Bean BOM

It contains all the modules available in the project

<dependency>
<groupId>com.expediagroup.beans</groupId>
<artifactId>bull-bom</artifactId>
<version>x.y.z</version>
<type>pom</type>
<scope>import</scope>
</dependency>

Bean Transformer

<dependency>
<groupId>com.expediagroup.beans</groupId>
<artifactId>bull-bean-transformer</artifactId>
<version>x.y.z</version>
</dependency>

Map Transformer

<dependency>
<groupId>com.expediagroup.beans</groupId>
<artifactId>bull-map-transformer</artifactId>
<version>x.y.z</version>
</dependency>

The project provides two different builds, one compatible with jdk 8 (or above), one with jdk 11 and on with jdk 17 or above.

In case you need to integrate it in a:

jdk 8 please refer to CHANGELOG-JDK8
jdk 11 please refer to CHANGELOG-JDK11
jdk 15CHANGELOG
Suggestions

Some jdk versions remove the Java Bean constructor's argument names from the compiled code and this may cause problems to the library. On top of that, it's suggested to configure the maven-compiler-plugin, inside your project, as follow:

<build>
...
<pluginManagement>
<plugins>
...
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>${maven.compiler.plugin.version}</version>
<configuration>
<source>${maven.compiler.source}</source>
<target>${maven.compiler.target}</target>
<parameters>true</parameters>
<forceJavacCompilerUse>true</forceJavacCompilerUse>
</configuration>
</plugin>
</plugins>
</pluginManagement>
...
</build>

Maven build

Full build

./mvnw clean install

or on Windows

mvnw.cmd clean install

Skip test coverage and checkstyle check

./mvnw clean install -P relaxed

or on Windows

mvnw.cmd clean install -P relaxed

Check for dependencies update

mvn versions:display-dependency-updates -P check-for-updates

or on Windows

mvnw.cmd versions:display-dependency-updates -P check-for-updates

Features:

support copy of immutable beans.
support copy of mutable beans.
support copy of hybrid beans (some fields private and some not).
support copy of Java Records.
support copy of Java beans without getter and setter methods.
support copy with Java primitive type.
support copy with Java Collection type. e.g. List<BeanA> => List<BeanB>
support copy with nested map fields. e.g. Map<String, Map<String, String>>
support copy with array containing primitive types. e.g. String[] => String[]
support copy with an array type. e.g. BeanA[] => BeanB[]
support copy with property name mapping. e.g. int id => int userId
support copy with recursion copy.
support validation through annotations.
support copy of beans with different field's name.
support lambda function field transformation.
support copy of java bean built through Builder.
easy usage, declarative way to define the property mapping (in case of different names), or simply adding the Lombok annotations.
allows setting the default value for all objects not existing in the source object.
allows skipping transformation for a given set of fields.
supports the retrieval of the value from getters if a field does not exist in the source object.
supports the automatic conversion of primitive types.

Feature samples

Bean transformation samples

Simple case:

publicclassFromBean { publicclassToBean {
privatefinalStringname; @NotNullprivatefinalBigIntegerid; publicBigIntegerid;
privatefinalList<FromSubBean> subBeanList; privatefinalStringname;
privateList<String> list; privatefinalList<String> list;
privatefinalFromSubBeansubObject; privatefinalList<ToSubBean> subBeanList;
privateImmutableToSubFoosubObject;
// all constructors // all args constructor// getters and setters... // getters and setters... 
}

And one line code as:

ToBeantoBean = beanUtils.getTransformer().transform(fromBean, ToBean.class);

Different field names copy:

From class and To class with different field names:

publicclassFromBean { publicclassToBean {
privatefinalStringname; privatefinalStringdifferentName;
privatefinalintid; privatefinalintid;
privatefinalList<FromSubBean> subBeanList; privatefinalList<ToSubBean> subBeanList;
privatefinalList<String> list; privatefinalList<String> list;
privatefinalFromSubBeansubObject; privatefinalToSubBeansubObject;
// getters...publicToBean(finalStringdifferentName,
finalintid,
} finalList<ToSubBean> subBeanList,
finalList<String> list,
finalToSubBeansubObject) {
this.differentName = differentName;
this.id = id;
this.subBeanList = subBeanList;
this.list = list;
this.subObject = subObject;
}
// getters... 
}

And one line code as:

beanUtils.getTransformer().withFieldMapping(newFieldMapping<>("name", "differentName")).transform(fromBean, ToBean.class);

it is also possible to map a field in the source class into multiple fields in the destination object.

Given the following source class:

public class SourceClass {
private final String name;
private final int id;
}

the following destination class:

public class DestinationClass {
private final String name;
private final int id;
private final int index;
}

and the following operations:

var sourceObj = new SourceClass("foo", 123);
var multipleFieldMapping = new FieldMapping<>("id", "index", "identifier");
var destObj = new BeanUtils().getBeanTransformer()
.withFieldMapping(multipleFieldMapping)
.transform(sourceObj, DestinationClass.class);
System.out.println("name = " + destObj.getName());
System.out.println("id = " + destObj.getId());
System.out.println("index = " + destObj.getIndex());

the output will be:

name = foo
id = 123
index = 123

Mapping destination fields with correspondent fields contained inside one of the nested objects in the source object:

Assuming that the object FromSubBean is declared as follow:

publicclassFromSubBean {
privateStringserialNumber;
privateDatecreationDate;
// getters and setters... 
}

and our source object and destination object are described as follow:

publicclassFromBean { publicclassToBean {
privatefinalintid; privatefinalintid;
privatefinalStringname; privatefinalStringname;
privatefinalFromSubBeansubObject; privatefinalStringserialNumber;
privatefinalDatecreationDate;
// all args constructor // all args constructor// getters... // getters... 
} }

the fields: serialNumber and creationDate needs to be retrieved from subObject, this can be done by defining the whole path to the end property:

FieldMappingserialNumberMapping = newFieldMapping<>("subObject.serialNumber", "serialNumber"); FieldMappingcreationDateMapping = newFieldMapping<>("subObject.creationDate", "creationDate");
beanUtils.getTransformer()
.withFieldMapping(serialNumberMapping, creationDateMapping)
.transform(fromBean, ToBean.class);

Different field names defining constructor args:

publicclassFromBean { publicclassToBean { privatefinalStringname; privatefinalStringdifferentName; privatefinalintid; privatefinalintid; privatefinalList<FromSubBean> subBeanList; privatefinalList<ToSubBean> subBeanList; privatefinalList<String> list; privatefinalList<String> list; privatefinalFromSubBeansubObject; privatefinalToSubBeansubObject; // all args constructor// getters...publicToBean(@ConstructorArg("name") finalStringdifferentName, @ConstructorArg("id") finalintid,
} @ConstructorArg("subBeanList") finalList<ToSubBean> subBeanList,
@ConstructorArg(fieldName ="list") finalList<String> list,
@ConstructorArg("subObject") finalToSubBeansubObject) {
this.differentName = differentName;
this.id = id;
this.subBeanList = subBeanList;
this.list = list;
this.subObject = subObject; }
// getters... 
}

And one line code as:

ToBeantoBean = beanUtils.getTransformer().transform(fromBean, ToBean.class);

Different field names and types applying transformation through lambda function:

publicclassFromBean { publicclassToBean { privatefinalStringname; @NotNullprivatefinalBigIntegerid; publicBigIntegeridentifier; privatefinalBigIntegerindex; publicBigIntegerindex; privatefinalList<FromSubBean> subBeanList; privatefinalStringname; privateList<String> list; privatefinalList<String> list; privatefinalFromSubBeansubObject; privatefinalList<ImmutableToSubFoo> nestedObjectList; privatefinalStringlocale; privatefinalLocalelocale; privateImmutableToSubFoonestedObject;
// constructors... // constructors...// getters and setters... // getters and setters...
} }

FieldTransformer<BigInteger, BigInteger> fieldTransformer = newFieldTransformer<>("identifier", BigInteger::negate);
FieldTransformer<String, Locale> localeTransformer = newFieldTransformer<>("locale", Locale::forLanguageTag);
beanUtils.getTransformer()
.withFieldMapping(newFieldMapping<>("id", "identifier"))
.withFieldTransformer(fieldTransformer).transform(fromBean, ToBean.class)
.withFieldTransformer(localeTransformer);

It's also possible to apply the same transformation function on multiple fields. Taking as an example the above bean and assuming that we would negate both the id and the identifier, the transformer function has to be defined as follows:

FieldTransformer<BigInteger, BigInteger> fieldTransformer = newFieldTransformer<>(List.of("identifier", "index"), BigInteger::negate);

Assign a default value in case of missing field in the source object:

Assign a default value in case of a missing field in the source object:

publicclassFromBean { publicclassToBean { privatefinalStringname; @NotNullprivatefinalBigIntegerid; publicBigIntegerid; privatefinalStringname; privateStringnotExistingField; // this will be null and no exceptions will be raised// constructors... // constructors...// getters... // getters and setters...
} }

And one line code as:

ToBeantoBean = beanUtils.getTransformer()
.setDefaultValueForMissingField(true).transform(fromBean, ToBean.class);

Disable the default value set for primitive types in case they are null:

BULL by default sets the default value for all primitive types fields in case their value is in the source object. Given the following Java Bean:

publicclassFromBean { publicclassToBean { privatefinalStringname; @NotNullprivatefinalBigIntegerid; publicBigIntegerid; privatefinalStringname; // constructors... // constructors...// getters... // getters and setters...
} }

in case the field id in the FromBean object is null, the value assigned the correspondent field in the ToBean object will be 0. To disable this you can simply do:

ToBeantoBean = beanUtils.getTransformer()
.setDefaultValueForMissingPrimitiveField(false).transform(fromBean, ToBean.class);

in this case, the field id after the transformation will be null

Applying a transformation function in case of missing fields in the source object:

Assign a default value in case of a missing field in the source object:

publicclassFromBean { publicclassToBean { privatefinalStringname; @NotNullprivatefinalBigIntegerid; publicBigIntegerid; privatefinalStringname; privateStringnotExistingField; // this will have value: sampleVal// all args constructor // constructors...// getters... // getters and setters...
} }

And one line code as:

FieldTransformer<String, String> notExistingFieldTransformer = newFieldTransformer<>("notExistingField", () -> "sampleVal");
ToBeantoBean = beanUtils.getTransformer()
.withFieldTransformer(notExistingFieldTransformer)
.transform(fromBean, ToBean.class);

Apply a transformation function on a field contained in a nested object:

This example shows how a lambda transformation function can be applied to a nested object field.

Given:

publicclassFromBean { publicclassToBean { privatefinalStringname; privatefinalStringname; privatefinalFromSubBeannestedObject; privatefinalToSubBeannestedObject; // all args constructor // all args constructor// getters... // getters...
} }

and

publicclassToSubBean { privatefinalStringname; privatefinallongindex; }

Assuming that the lambda transformation function should be applied only to field: name contained into the ToSubBean object, the transformation function has to be defined as follow:

FieldTransformer<String, String> nameTransformer = newFieldTransformer<>("nestedObject.name", StringUtils::capitalize);
ToBeantoBean = beanUtils.getTransformer()
.withFieldTransformer(nameTransformer)
.transform(fromBean, ToBean.class);

Map a primitive type field in the source object into a nested object:

This example shows how to map a primitive field into a nested object into the destination one.

Given:

publicclassFromBean { publicclassToBean { privatefinalStringname; privatefinalStringname; privatefinalFromSubBeannestedObject; privatefinalToSubBeannestedObject; privatefinalintx;
// all args constructor // all args constructor// getters... // getters...
} }

and

publicclassToSubBean { privatefinalintx;
// all args constructor
} // getters...

Assuming that the value x should be mapped into the field: x contained into the ToSubBean object, the field mapping has to be defined as follow:

ToBeantoBean = beanUtils.getTransformer()
.withFieldMapping(newFieldMapping<>("x", "nestedObject.x"));

Apply a transformation function on all fields matching with the given one:

This example shows how a lambda transformation function can be applied to all fields matching with the given one independently from their position.

Given:

publicclassFromBean { publicclassToBean { privatefinalStringname; privatefinalStringname; privatefinalFromSubBeannestedObject; privatefinalToSubBeannestedObject; // all args constructor // all args constructor// getters... // getters...
} }

and

publicclassFromSubBean { publicclassToSubBean { privatefinalStringname; privatefinalStringname; privatefinallongindex; privatefinallongindex; // all args constructor // all args constructor// getters... // getters...
} }

Assuming that the lambda transformation function should be applied only to the field: name contained in the ToSubBean object, the transformation function has to be defined as follow:

FieldTransformer<String, String> nameTransformer = newFieldTransformer<>("name", StringUtils::capitalize);
ToBeantoBean = beanUtils.getTransformer()
.setFlatFieldNameTransformation(true)
.withFieldTransformer(nameTransformer)
.transform(fromBean, ToBean.class);

Static transformer function:

List<FromFooSimple> fromFooSimpleList = Arrays.asList(fromFooSimple, fromFooSimple);

can be transformed as follow:

Function<FromFooSimple, ImmutableToFooSimple> transformerFunction = BeanUtils.getTransformer(ImmutableToFooSimple.class);
List<ImmutableToFooSimple> actual = fromFooSimpleList.stream()
.map(transformerFunction)
.collect(Collectors.toList());

or if you have a pre-configured transformer:

Function<FromFooSimple, ImmutableToFooSimple> transformerFunction = BeanUtils.getTransformer(<yourPreconfiguredTransformer>, ImmutableToFooSimple.class);
List<ImmutableToFooSimple> actual = fromFooSimpleList.stream()
.map(transformerFunction)
.collect(Collectors.toList());

Enable Java Beans validation:

Assuming that the field: id in the fromBean instance is null.

publicclassFromBean { publicclassToBean { privatefinalStringname; @NotNullprivatefinalBigIntegerid; publicBigIntegerid; privatefinalStringname;
// all args constructor // all args constructor// getters... // getters and setters...
} }

adding the following configuration an exception will be thrown:

ToBeantoBean = beanUtils.getTransformer()
.setValidationEnabled(true)
.transform(fromBean, ToBean.class);

Copy on an existing instance:

Given:

publicclassFromBean { publicclassToBean { privatefinalStringname; privateStringname; privatefinalFromSubBeannestedObject; privateToSubBeannestedObject; // all args constructor // constructor// getters... // getters and setters...
} }

if you need to perform the copy on an already existing object, just do:

ToBeantoBean = newToBean();
beanUtils.getTransformer().transform(fromBean, toBean);

Skip transformation on a given set of fields:

Given:

publicclassFromBean { publicclassToBean { privatefinalStringname; privateStringname; privatefinalFromSubBeannestedObject; privateToSubBeannestedObject; // all args constructor // constructor// getters... // getters and setters...
} }
publicclassFromBean2 { privatefinalintindex; privatefinalFromSubBeannestedObject;
// all args constructor // getters... 
}

if you need to skip the transformation for a given field, just do:

ToBeantoBean = newToBean();
beanUtils.getTransformer()
.skipTransformationForField("nestedObject")
.transform(fromBean, toBean);

where nestedObject is the name of the field in the destination object.

This feature allows us to transform an object keeping the data from different sources.

To better explain this function let's assume that the ToBean (defined above) should be transformed as follow:

name field value has been taken from the FromBean object
nestedObject field value has been taken from the FromBean2 object

the objective can be reached by doing:

// create the destination objectToBeantoBean = newToBean();
// execute the first transformation skipping the copy of: 'nestedObject' field that should come from the other source objectbeanUtils.getTransformer()
.skipTransformationForField("nestedObject")
.transform(fromBean, toBean);
// then execute the transformation skipping the copy of: 'name' field that should come from the other source objectbeanUtils.getTransformer()
.skipTransformationForField("name")
.transform(fromBean2, toBean);

Keep a field type value from the source object as is:

Given:

publicclassFromBean { publicclassToBean { privatefinalStringname; privateStringname; privatefinalDateTimedateTime; privatefinalDateTimedateTime; // all args constructor // constructor// getters... // getters and setters...
} }

if you need to keep the value of a field type from the source object as it, you can add all the types you want to keep as they are by doing:

ClassUtils.CUSTOM_SPECIAL_TYPES.add(DateTime.class);
ToBeantoBean = newToBean();
beanUtils.getTransformer()
.transform(fromBean, toBean);

Not existing field in the source object:

In case the destination class has a field that does not exist in the source object, but it contains a getter method returning the value, the library should gets the field value from that method.

publicclassFromBean { publicclassToBean { privatefinalBigIntegerid;
publicBigIntegergetId() { returnBigInteger.TEN; // all args constructor
} // getters...
} }

And one line code as:

ToBeantoBean = beanUtils.getTransformer().transform(fromBean, ToBean.class);

Transform primitive types automatically

Given the following Java Bean:

publicclassFromBean { publicclassToBean { privatefinalStringindexNumber; privatefinalintindexNumber; privatefinalBigIntegerid; publicLongid; // constructors... // constructors...// getters... // getters and setters...
} }

as, by default the primitive type conversion is disabled, to get the above object converted we should have implemented transformer functions for both field indexNumber and id, but this can be done automatically by enabling the the functionality described above.

Transformertransformer = beanUtils.getTransformer()
.setPrimitiveTypeConversionEnabled(true);
ToBeantoBean = transformer.transform(fromBean, ToBean.class);

IMPORTANT: The primitive type transformation (if enabled) is executed before any other FieldTransformer function is defined on a specific field. This means that once the FieldTransformer function will be executed the field value has already been transformed.

Builder supported patterns

The library supports the transformation of Java Bean using the following Builder patterns:

Standard pattern:

publicclassItemType {
privatefinalClass<?> objectClass;
privatefinalClass<?> genericClass;
ItemType(finalClass<?> objectClass, finalClass<?> genericClass) {
this.objectClass = objectClass;
this.genericClass = genericClass;
}
publicstaticItemTypeBuilderbuilder() {
returnnewItemType.ItemTypeBuilder();
}
// getter methodspublicstaticclassItemTypeBuilder {
privateClass<?> objectClass;
privateClass<?> genericClass;
ItemTypeBuilder() {
}
publicItemTypeBuilderobjectClass(finalClass<?> objectClass) {
this.objectClass = objectClass;
returnthis;
}
publicItemTypeBuildergenericClass(finalClass<?> genericClass) {
this.genericClass = genericClass;
returnthis;
}
publicItemTypebuild() {
returnnewItemType(this.objectClass, this.genericClass);
}
}
}

Custom Builder pattern:

To enable the transformation of Java Beans using the following Builder pattern:

publicclassItemType {
privatefinalClass<?> objectClass;
privatefinalClass<?> genericClass;
ItemType(finalItemTypeBuilderbuilder) {
this.objectClass = builder.objectClass;
this.genericClass = builder.genericClass;
}
publicstaticItemTypeBuilderbuilder() {
returnnewItemType.ItemTypeBuilder();
}
// getter methodspublicstaticclassItemTypeBuilder {
privateClass<?> objectClass;
privateClass<?> genericClass;
ItemTypeBuilder() {
}
publicItemTypeBuilderobjectClass(finalClass<?> objectClass) {
this.objectClass = objectClass;
returnthis;
}
publicItemTypeBuildergenericClass(finalClass<?> genericClass) {
this.genericClass = genericClass;
returnthis;
}
publicItemTypebuild() {
returnnewItemType(this);
}
}
}

It's needed to enable the custom Builder Transformation as follows:

ToBeantoBean = newBeanTransformer()
.setCustomBuilderTransformationEnabled(true)
.transform(sourceObject, ToBean.class);

Transform Java Record

Simple case:

publicrecordFromFooRecord(BigIntegerid, Stringname) { publicrecordRecordToFoo(BigIntegerid, Stringname) { } }

And one line code as:

vartoBean = beanUtils.getTransformer().transform(fromBean, RecordToFoo.class);

Constraints:

the class's fields that have to be copied must not be static

More sample beans can be found in the test package: com.expediagroup.beans.sample

Third-party library comparison

Following a comparison between the BULL functionalities and the following Third-Party libraries:

	BULL	Apache Bean Utils	Jackson	Dozer
Mutable bean copy	X	X	X	X+
Mutable bean with nested objects	X	-	X	X+
Mutable bean extending classes	X	-	X	X+
Immutable bean copy	X	-	-	X*
Mixed bean copy	X	-	-	X+
Copy of beans without getter and setter methods defined	X	-	-	-
Mutable Bean with different field's name	X	-	-	X+
Mixed with different field's type	X	-	-	X+
Immutable with different field's type	X	-	-	X+
Mutable Bean containing collection type fields containing complex objects	X	-	X	X
Mixed Bean containing collection type fields containing complex objects	X	-	-	X+
Immutable Bean containing collection type fields containing complex objects	X	-	-	X+
Mutable Bean containing containing Map type fields with nested Maps inside. e.g. `Map<String, Map<String, Integer>>`	X	-	X	X
Mixed Bean containing containing Map type fields with nested Maps inside. e.g. `Map<String, Map<String, Integer>>`	X	-	-	X+
Immutable Bean containing containing Map type fields with nested Maps inside. e.g. `Map<String, Map<String, Integer>>`	X	-	-	X+
Annotation field validation	X	-	X	-

[*] Immutable types are not supported by Dozer. When a type doesn't have a no-arg constructor and all fields are final, Dozer can't perform the mapping. A workaround is introducing the Builder Pattern. An example can be found here[+] Requires a custom configuration

Performance

Let's have a look at the performance library performance. The test has been executed on the following objects:

Mutable objects
Mutable objects extending another mutable object
Immutable objects
Immutable objects extending another immutable object
Mixed objects

	Mutable	Immutable	Mixed
Simple objects (without nested objects)	~0.011ms	~0.018ms	NA
Complex objects (containing several nested object and several items in Map and Array objects)	~0.37ms	~0.21ms	~0.22ms
CPU/Heap usage	~0.2%/35 MB	~0.2%/30 MB	~0.2%/25 MB

Transformation time screenshot

Real case testing

The Bean Utils library has been tested on a real case scenario integrating it into a real edge service (called BPE). The purpose was to compare the latency introduced by the library plus the memory/CPU usage. The dashboard's screenshot shows the latency of the invoked downstream service (called BPAS) and the one where the library has been installed (BPE). Following the obtained results:

	Classic transformer	BeanUtils library
Throughput per second	60	60
Average CPU usage	0.3%	0.3%
Min/Max Heap Memory Usage (MB)	90/320	90/320
Average Latency than the downstream service	+2ms	+2ms
JVM stats screenshot	screenshot	screenshot
Dashboard screenshot	screenshot	screenshot

Validation samples

Validating a java bean has never been so simple. The library offers different APIs related to this, following some examples:

Validate a Java Bean:

Given the following bean:

publicclassSampleBean { @NotNullprivateBigIntegerid; privateStringname; // constructor// getters and setters... 
}

an instance of the above object:

SampleBeansampleBean = newSampleBean();

And one line code as:

beanUtils.getValidator().validate(sampleBean);

this will throw an InvalidBeanException as the id field is null.

Retrieve the violated constraints:

Given the following bean:

publicclassSampleBean { @NotNullprivateBigIntegerid; privateStringname; // constructor// getters and setters... 
}

an instance of the above object:

SampleBeansampleBean = newSampleBean();

And one line code as:

List<String> violatedConstraints = beanUtils.getValidator().getConstraintViolationsMessages(sampleBean);

this will return a list containing a constraint validation message for the id field as it's null and the constraint: @NotNull is not met.

in case it's needed to have the ConstraintViolation object:

Set<ConstraintViolation<Object>> violatedConstraints = beanUtils.getValidator().getConstraintViolations(sampleBean);

Primitive type object converter

Converts a given primitive value into the given primitive type. The supported types, in which an object can be converted (from/to), are:

Byte, byte or byte[]
Short or short
Integer or int
Long or long
Float or float
Double or double
BigDecimal
BigInteger
Character or char
Boolean or boolean
String

Convert a String into an int:

Given the following variable:

StringindexNumber = "26062019";

to convert it in an int:

Converterconverter = newBeanUtils().getPrimitiveTypeConverter();
intindexNumber = converter.convertValue(indexNumber, int.class);

Obtain a conversion function that converts from char to byte:

It's possible to obtain a type conversion function, reusable several times in different places. Assuming that the required conversion is from char to `byte

charc = '1';

the conversion function is retrieved through:

Converterconverter = newBeanUtils().getPrimitiveTypeConverter();
Optional<Function<Object, Object>> conversionFunction = converter.getConversionFunction(char.class, byte.class);
byteconverted = conversionFunction.map(processor -> processor.apply(c)).orElse(0);

in case the conversion is not needed as the primitive type and the destination type are the same it will return an empty Optional
in case the conversion function is unavailable or no not possible the method throws a: TypeConversionException

`Map` transformation samples

Samples on how to transform a Map and all others function applicable to it can be viewed here

Documentation

Detailed project documentation is available here, including some samples for testing the library inside your project.

An article that explains how it works, with suggestions and examples, is available on DZone: How to Transform Any Type of Java Bean With BULL

Credits

Created by: Fabio Borriello with the contribution of: Patrizio Munzi, Andrea Marsiglia, Giorgio Delle Grottaglie & the Hotels.com's Checkout team in Rome.

The application's logo has been designed by Rob Light.

Release

All the instructions for releasing a new version are available at RELEASES.md

Badge your project

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[![Bull enabled](https://img.shields.io/badge/bull-enabled-red?logo=data:image/png;base64,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)](https://github.com/ExpediaGroup/bull)

Support

For any question, proposal, or help, please refer to the slack channel: #bull.

Legal

This project is available under the Apache 2.0 License.

Name		Name	Last commit message	Last commit date
.github		.github
.mvn		.mvn
bull-bean-transformer		bull-bean-transformer
bull-benchmark		bull-benchmark
bull-bom		bull-bom
bull-common		bull-common
bull-converter		bull-converter
bull-map-transformer		bull-map-transformer
bull-report		bull-report
bull-transformer-generator		bull-transformer-generator
config		config
docs/site		docs/site
.gitignore		.gitignore
CHANGELOG-JDK11.md		CHANGELOG-JDK11.md
CHANGELOG-JDK8.md		CHANGELOG-JDK8.md
CHANGELOG.md		CHANGELOG.md
CONTRIBUTING.md		CONTRIBUTING.md
CONTRIBUTORS.md		CONTRIBUTORS.md
LICENSE		LICENSE
README.md		README.md
RELEASE.md		RELEASE.md
_config.yml		_config.yml
benchmark.sh		benchmark.sh
code-of-conduct.md		code-of-conduct.md
lombok.config		lombok.config
mvnw		mvnw
mvnw.cmd		mvnw.cmd
pom.xml		pom.xml

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Bean Utils Light Library

Start using

Bean BOM

Bean Transformer

Map Transformer

Suggestions

Maven build

Skip test coverage and checkstyle check

Check for dependencies update

Features:

Feature samples

Bean transformation samples

Simple case:

Different field names copy:

Mapping destination fields with correspondent fields contained inside one of the nested objects in the source object:

Different field names defining constructor args:

Different field names and types applying transformation through lambda function:

Assign a default value in case of missing field in the source object:

Disable the default value set for primitive types in case they are null:

Applying a transformation function in case of missing fields in the source object:

Apply a transformation function on a field contained in a nested object:

Map a primitive type field in the source object into a nested object:

Apply a transformation function on all fields matching with the given one:

Static transformer function:

Enable Java Beans validation:

Copy on an existing instance:

Skip transformation on a given set of fields:

Keep a field type value from the source object as is:

Not existing field in the source object:

Transform primitive types automatically

Builder supported patterns

Standard pattern:

Custom Builder pattern:

Transform Java Record

Simple case:

Constraints:

Third-party library comparison

Performance

Real case testing

Validation samples

Validate a Java Bean:

Retrieve the violated constraints:

Primitive type object converter

Convert a String into an int:

Obtain a conversion function that converts from char to byte:

Map transformation samples

Documentation

Credits

Related articles

Release

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Support

Legal

About

Topics

Resources

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Used by

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`Map` Transformer

`Map` transformation samples