I have a Service class that has a generic type and a setController method that is based on the same generic type. the generic type of the servic object is only known at the time of declaration.
The problem is now when i define a ControllerImpl where the generic type is defined the #Autowired method of setController does not use that component.
Has somebody an idea how to fix it and keep the ServiceImpl generic. (it would work when i define the typ in ServiceImpl as well).
The following example show the problem i'm facing with:
#SpringBootTest
#ActiveProfiles("local")
public class AccessTest {
#Autowired
private ServiceA<BeanA> service;
#Test
void test(){
Assertions.assertNotNull(service.controller);
}
interface ValueGetter{
}
static class BeanA implements ValueGetter{
}
static class AbstractService<B extends ValueGetter>{
Controller<B> controller;
#Autowired
void setController(#Nullable Controller<B> controller){
this.controller = controller;
}
}
interface Controller<B extends ValueGetter>{
void doSomething(B value);
}
//not inner class
#Service
public class ServiceA<B extends AccessTest.ValueGetter> extends AccessTest.AbstractService<B> {
}
//not inner class
#Component
public class ControllerImpl implements AccessTest.Controller<AccessTest.BeanA> {
#Override
public void doSomething(final AccessTest.BeanA value) {
}
}
}
Related
I am having below mapper class in which I want to use CounterService. I am trying constructor injection but that's not working and null is printing.
#Mapper(componentModel = "spring", uses = CounterService.class, injectionStrategy = InjectionStrategy.CONSTRUCTOR)
public abstract class CarMapper {
private CounterService counterService;
public CarMapper(CounterService counterService) {
this.counterService = counterService;
}
public abstract Car dtoToEntity(CarDto carDto);
public CarDto entityToDto(Car car) {
System.out.println(counterService)
//....
return carDto;
}
}
Implementation class by mapStruct
#Component
public class CarMapperImpl extends CarMapper{
#Override
public Car dtoToEntity(CarDto carDto){
//...
}
}
If I use field injection using #AutoWired, that way it works fine. It means Spring doesn't support the constructor injection of abstract class. Is it because abstract class can't be instantiated directly and require a subclass to instantiate?
Is there any way mapStruct can create a constructor inside the implementation class as:
public CarMapperImpl(CounterService counterService){
super(counterService);
}
That way, constructor injection should work.
This has nothing to do with Spring. It was a deliberate decision done by the MapStruct team to not use super constructors.
What you can do though is to use setter injection.
#Mapper(componentModel = "spring", uses = CounterService.class, injectionStrategy = InjectionStrategy.CONSTRUCTOR)
public abstract class CarMapper {
private CounterService counterService;
public abstract Car dtoToEntity(CarDto carDto);
public CarDto entityToDto(Car car) {
System.out.println(counterService)
//....
return carDto;
}
#Autowired
public void setCounterService(CounterService counterService) {
this.counterService = counterService;
}
}
You can also use a Mapper Decorator like below. Also, always make sure to check the generated class.
#DecoratedWith(CarDecoratorMapper.class)
#Mapper(componentModel = "spring")
public interface CarMapper {
Car dtoToEntity(CarDto carDto);
CarDto entityToDto(Car car);
}
public abstract class CarDecoratorMapper implements CarMapper {
#Autowired
private CarMapper delegate;
#Autowired
private CounterService counterService;
public Car dtoToEntity(CarDto carDto) {
Car car = delegate.dtoToEntity(carDto);
car.setProperty(counterService.count(carDto));
return car;
}
public CarDto entityToDto(Car car) {
CarDto carDto = delegate.entityToDto(car);
carDto.setProperty(counterService.countDto(car));
return carDto;
}
}
You don't have to use setter injection you can do the same what Filip suggested and just use field injection. If you don't need a setter of course
In normal Spring, when we want to autowire an interface, we define it's implementation in Spring context file.
What about Spring boot?
how can we achieve this?
currently we only autowire classes that are not interfaces.
Another part of this question is about using a class in a Junit class inside a Spring boot project.
If we want to use a CalendarUtil for example, if we autowire CalendarUtil, it will throw a null pointer exception. What can we do in this case? I just initialized using "new" for now...
Use #Qualifier annotation is used to differentiate beans of the same interface
Take look at Spring Boot documentation
Also, to inject all beans of the same interface, just autowire List of interface
(The same way in Spring / Spring Boot / SpringBootTest)
Example below:
#SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
public interface MyService {
void doWork();
}
#Service
#Qualifier("firstService")
public static class FirstServiceImpl implements MyService {
#Override
public void doWork() {
System.out.println("firstService work");
}
}
#Service
#Qualifier("secondService")
public static class SecondServiceImpl implements MyService {
#Override
public void doWork() {
System.out.println("secondService work");
}
}
#Component
public static class FirstManager {
private final MyService myService;
#Autowired // inject FirstServiceImpl
public FirstManager(#Qualifier("firstService") MyService myService) {
this.myService = myService;
}
#PostConstruct
public void startWork() {
System.out.println("firstManager start work");
myService.doWork();
}
}
#Component
public static class SecondManager {
private final List<MyService> myServices;
#Autowired // inject MyService all implementations
public SecondManager(List<MyService> myServices) {
this.myServices = myServices;
}
#PostConstruct
public void startWork() {
System.out.println("secondManager start work");
myServices.forEach(MyService::doWork);
}
}
}
For the second part of your question, take look at this useful answers first / second
You can also make it work by giving it the name of the implementation.
Eg:
#Autowired
MyService firstService;
#Autowired
MyService secondService;
Assume that you have a GreetingService
public interface GreetingService {
void doGreetings();
}
And you have 2 implementations HelloService
#Service
#Slf4j
public class HelloService implements GreetingService{
#Override
public void doGreetings() {
log.info("Hello world!");
}
}
and HiService
#Slf4j
#Service
public class HiService implements GreetingService{
#Override
public void doGreetings() {
log.info("Hi world!");
}
}
Then you have another interface, which is BusinessService to call some business
public interface BusinessService {
void doGreetings();
}
There are some ways to do that
#1. Use #Autowired
#Component
public class BusinessServiceImpl implements BusinessService{
#Autowired
private GreetingService hiService; // Spring automatically maps the name for you, if you don't want to change it.
#Autowired
private GreetingService helloService;
#Override
public void doGreetings() {
hiService.doGreetings();
helloService.doGreetings();
}
}
In case you need to change your implementation bean name, refer to other answers, by setting the name to your bean, for example #Service("myCustomName") and applying #Qualifier("myCustomName")
#2. You can also use constructor injection
#Component
public class BusinessServiceImpl implements BusinessService {
private final GreetingService hiService;
private final GreetingService helloService;
public BusinessServiceImpl(GreetingService hiService, GreetingService helloService) {
this.hiService = hiService;
this.helloService = helloService;
}
#Override
public void doGreetings() {
hiService.doGreetings();
helloService.doGreetings();
}
}
This can be
public BusinessServiceImpl(#Qualifier("hiService") GreetingService hiService, #Qualifier("helloService") GreetingService helloService)
But I am using Spring Boot 2.6.5 and
public BusinessServiceImpl(GreetingService hiService, GreetingService helloService)
is working fine, since Spring automatically get the names for us.
#3. You can also use Map for this
#Component
#RequiredArgsConstructor
public class BusinessServiceImpl implements BusinessService {
private final Map<String, GreetingService> servicesMap; // Spring automatically get the bean name as key
#Override
public void doGreetings() {
servicesMap.get("hiService").doGreetings();
servicesMap.get("helloService").doGreetings();
}
}
List also works fine if you run all the services. But there is a case that you want to get some specific implementation, you need to define a name for it or something like that. My reference is here
For this one, I use #RequiredArgsConstructor from Lombok.
As mentioned in the comments, by using the #Qualifier annotation, you can distinguish different implementations as described in the docs.
For testing, you can use also do the same. For example:
#RunWith(SpringRunner.class)
#SpringBootTest
public class MyClassTests {
#Autowired
private MyClass testClass;
#MockBean
#Qualifier("default")
private MyImplementation defaultImpl;
#Test
public void givenMultipleImpl_whenAutowiring_thenReturnDefaultImpl() {
// your test here....
}
}
There are 2 approaches when we have autowiring of an interface with multiple implementations:
Spring #Primary annotation
In short it tells to our Spring application whenever we try to autowire our interface to use that specific implementation which is marked with the #Primary annotation. It is like a default autowiring setting. It can be used only once per cluster of implementations of an interface. → #Primary Docs
Spring #Qualifier annotation
This Spring annotation is giving us more control to select the exact implementation wherever we define a reference to our interface choosing among its options. → #Qualifier Docs
For more details follow the links to their documentation.
public interface SomeInterfaces {
void send(String message);
String getType();
}
kafka-service
#Component
public class SomeInterfacesKafkaImpl implements SomeInterfaces {
private final String type = "kafka";
#Override
public void send(String message) {
System.out.println(message + "through Kafka");
}
#Override
public String getType() {
return this.type;
}
}
redis-service
#Component
public class SomeInterfacesRedisImpl implements SomeInterfaces {
private final String type = "redis";
#Override
public void send(String message) {
System.out.println(message + "through Redis");
}
#Override
public String getType() {
return this.type;
}
}
master
#Component
public class SomeInterfacesMaster {
private final Set<SomeInterfaces> someInterfaces;
public SomeInterfacesMaster(Set<SomeInterfaces> someInterfaces) {
this.someInterfaces = someInterfaces;
}
public void sendMaster(String type){
Optional<SomeInterfaces> service =
someInterfaces
.stream()
.filter(service ->
service.getType().equals(type)
)
.findFirst();
SomeInterfaces someService =
service
.orElseThrow(() -> new RuntimeException("There is not such way for sending messages."));
someService .send(" Hello. It is a letter to ....");
}
}
test
#SpringBootTest
public class MultiImplementation {
}
#TestInstance(TestInstance.Lifecycle.PER_CLASS)
class SomeInterfacesMasterTest extends MultiImplementation {
#Autowired
private SomeInterfacesMaster someInterfacesMaster;
#Test
void sendMaster() {
someInterfacesMaster.sendMaster("kafka");
}
}
Thus, according to the Open/Closed principle, we only need to add an implementation without breaking existing code.
#Component
public class SomeInterfacesRabbitImpl implements SomeInterfaces {
private final String type = "rabbit";
#Override
public void send(String message) {
System.out.println(message + "through Rabbit");
}
#Override
public String getType() {
return this.type;
}
}
test-v2
#TestInstance(TestInstance.Lifecycle.PER_CLASS)
class SomeInterfacesMasterTestV2 extends MultiImplementation {
#Autowired
private SomeInterfacesMaster someInterfacesMaster;
#Test
void sendMasterV2() {
someInterfacesMaster.sendMaster("rabbit");
}
}
If we have multiple implementations of the same interface, Spring needs to know which one it should be autowired into a class. Here is a simple example of validator for mobile number and email address of Employee:-
Employee Class:
public class Employee {
private String mobileNumber;
private String emailAddress;
...
/** Getters & Setters omitted **/
}
Interface EmployeeValidator:
public interface EmployeeValidator {
public Employee validate(Employee employee);
}
First implementation class for Mobile Number Validator:
#Component(value="EmployeeMobileValidator")
public class EmployeeMobileValidator implements EmployeeValidator {
#Override
public Employee validate(Employee employee) {
//Mobile number Validation logic goes here.
}
}
Second implementation class for Email address Validator:
#Component(value="EmployeeEmailValidator")
public class EmployeeEmailValidator implements EmployeeValidator {
#Override
public Employee validate(Employee employee) {
//Email address validation logic goes here.
}
}
We can now autowired these above validators individually into a class.
Employee Service Interface:
public interface EmployeeService {
public void handleEmployee(Employee employee);
}
Employee Service Implementation Class
#Service
public class EmployeeServiceImpl implements EmployeeService {
/** Autowire validators individually **/
#Autowired
#Qualifier("EmployeeMobileValidator") // Autowired using qualifier for mobile validator
private EmployeeValidator mobileValidator;
#Autowired
#Qualifier("EmployeeEmailValidator") // Autowired using qualifier for email valodator
private EmployeeValidator emailValidator;
#Override
public void handleEmployee(Employee employee) {
/**You can use just one instance if you need**/
employee = mobileValidator.validate(employee);
}
}
I have classes which implements MyInterface and their names are for example:
MyClassA, MyClassB etc.
How can I get the instance of the class by it's bean name? Something like:
context.getBean("myClassA")
context.getBean("myClassB")
Can I do it without configuring beans in the XML?
I want to use annotations
You can use qualifiers, e.g:
#Component
#Qualifier("classA")
public MyInterface ClassA {
return new ClassA();
}
#Component
#Qualifier("classB")
public MyInterface ClassB {
return new ClassB();
}
and use it like:
public class SomeClass {
#Autowired
#Qualifier("classA")
private MyInterface classA;
}
You have several options here. The easiest one would be using field names as a component name using #Autowire:
#Component("testClassA") // It is possible to omit explicit bean name declaration here since Spring will use a class name starting from lower case letter as a bean name by default. So just `#Component` should be sufficient here and below.
public TestClassA implements MyInterface {
}
#Component("testClassB")
public TestClassB implements MyInterface {
}
/*
* Note that field names are the same as the component names.
*/
#Component
public class TestClassWithDependencies {
#Autowired
private MyInterface testClassA;
#Autowired
private MyInterface testClassB;
}
Another option is to use qualifiers:
#Component
#Qualifier("testClassA")
public TestClassA implements MyInterface {
}
#Component
#Qualifier("testClassB")
public TestClassB implements MyInterface {
}
#Component
public class TestClassWithDependencies {
#Autowired
#Qualifier("testClassA")
private MyInterface testClassA;
#Autowired
#Qualifier("testClassB")
private MyInterface testClassB;
}
You could even create your own meta-annotations when you need to use the same qualifiers over and over again:
#Target({ElementType.FIELD, ElementType.PARAMETER})
#Retention(RetentionPolicy.RUNTIME)
#Qualifier("testClassA")
public #interface TestClassACustomQualifier {
String value();
}
#Target({ElementType.FIELD, ElementType.PARAMETER})
#Retention(RetentionPolicy.RUNTIME)
#Qualifier("testClassB")
public #interface TestClassBCustomQualifier {
String value();
}
#Component
public class TestClassWithDependencies {
#Autowired
#TestClassACustomQualifier
private MyInterface testClassA;
#Autowired
#TestClassBCustomQualifier
private MyInterface testClassB;
}
Much prettier, isn't it? One more option is to use #Resource from JSR-250 specification. As pointed out by #hovanessyan it's more JavaEE style of doing things, but still, I think it's a viable approach used on many projects:
#Component("testClassA")
public TestClassA implements MyInterface {
}
#Component("testClassB")
public TestClassB implements MyInterface {
}
#Component
public class TestClassWithDependencies {
#Resource(name="testClassA")
private MyInterface testClassA;
#Resource(name="testClassB")
private MyInterface testClassB;
}
More information you can get on https://www.sourceallies.com/2011/08/spring-injection-with-resource-and-autowired/, where discussed different approaches with tests added.
Hope this helps!
I think if above options don't suffice then factory implementation is one way to get instance on the fly -
#Component
public TestClassA implements MyInterface {
}
#Component
public TestClassB implements MyInterface {
}
define you factory this way -
public class MyInterfaceFactory extends AbstractFactoryBean<MyInterface> {
private String filter;
#Override
public Class<?> getObjectType() {
return MyInterface.class;
}
#Override
protected MyInterface createInstance() throws Exception {
MyInterface myInterface;
switch (filter)
{
case "1":
myInterface = new TestClassA();
break;
case "2":
myInterface = new TestClassB();
break;
default: throw new IllegalArgumentException("No such type.");
}
return myInterface;
}
}
and then your bean config -
#Configuration
public class FactoryBeanConfig {
#Bean(name = "myInterface")
public MyInterfaceFactory myInterfaceFactory() {
MyInterfaceFactory factory = new MyInterfaceFactory();
factory.setFilter("7070");
return factory;
}
}
I'm having a Spring boot application in which based on a variable, I need to call corresponding implementation classes of an interface. This is what I have right now:
public interface Parent{
public void call();
}
public class ABC implements Parent{
public void call(){
System.out.println("Called ABC");
}
}
public class XYZ implements Parent{
public void call(){
System.out.println("Called XYZ");
}
}
#Service("caller")
public class Caller{
#Autowired
protected OrderInfoRepository orderInfoRepository;
AnnotationConfigApplicationContext context;
public Caller(){
context = new AnnotationConfigApplicationContext(Config.class);
}
public void callMethod(String param){
Parent p = (Parent) context.getBean(param+"_Caller");
p.call();
}
}
#Configuration
public class Config{
#Bean(name="ABC_Caller")
public Parent getABC(){
return new ABC();
}
#Bean(name="XYZ_Caller")
public Parent getXYZ(){
return new XYZ();
}
}
#Repository
public interface MyRepo extends Repository<MyDAO, Long> {
// ....
}
Basically what I want to do is, based on the param passed to Caller.callMethod(), I want to add "_Caller" to the param, and call the corresponding implementation class. So, I'm defining a #Configuration class, where I define which implementation class to return. And then using the AnnotationConfigApplicationContext, I get the corresponding bean. This works fine.
The problem I'm having is, when I try to Autowire anything in the implementation classes, I get a NoSuchBeanDefinitionException. For instance, when I autowire in the implementation class ABC
public class ABC implements Parent{
#Autowired
MyRepo myRepo;
public void call(){
System.out.println("Called ABC");
}
}
I get Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.persistence.repositories.MyRepo] when I try to start the application. However, when I do the Autowiring in the Caller class instead, it works fine. I had asked a similar question a while back, but was not able to resolve it. Any ideas?
public abstract class AService<T> {
public T needsToBeAdvised(T param) {
T result = doSomething(param);
return result;
}
}
#Service
public class BService extends AService<B> {
#Override
public T needsToBeAdvised(T param) {
return super.needsToBeAdvised(param);
}
}
#Service
public class CService extends AService<C> {}
// (B & C implement an interface AType)
#Component
#Aspect
public class MyAspect {
#Pointcut("execution(* package.AService+.needsToBeAdvised(*))")
private void aNeedToBeAdvised() {}
#AfterReturning(pointcut="aNeedToBeAdvised()", returning="param")
public void interceptNeedsToBeAdvised(JoinPoint joinPoint, AType param) {
// some action
}
}
Given this setup:
bService.needsToBeAdvised(bParam) //is intercepted
but,
cService.needsToBeAdvised(cParam) //is NOT.
How do I achieve this without overriding needsToBeAdvised() in CService?
EDIT:
I should add that BService and CService are both in the same package.
If I change my point-cut to the following:
#Pointcut("execution(* package.CService.needsToBeAdvised(*))")
cService.needsToBeAdvised(cParam) //is still not intercepted
The only way it works is if I override needsTobeAdvised() in CService
Are all services in the same package? Given from your example code, I suspect AService and BService to be in the package package, but CService to be in another package. If services indeed are in different packages, you have some options:
Move so that they are in the same package
Change you pointcut to be more generic, e.g. "execution(* *.A+.needsToBeAdvised(*))
Add more pointcuts