Develop Reference

How to get Service from another class?

I'm creating telegram bot with Spring-Boot. I have AscractState class:
public abstract class AbstractState {
boolean isInputIndeed = Boolean.FALSE;
public abstract void handleInput(BotContext context);
//another parts
}
And there is extend which is
#Slf4j
public class AgeInputState extends AbstractState {
#Autowired
ClientService clientService;
public AgeInputState(boolean isInputIndeed) {
super(isInputIndeed, State.AGE_INPUT);
}
#Override
public void handleInput(BotContext context) {
context.getClient().setAge(Integer.parseInt(context.getInput()));
clientService.updateUser(context.getClient());
}
}
But i have touble with ClientService. Which annotations on class i need to add for autowiring this fiels?

Since this class has a constructor which only accepts a boolean, I assume you're needing to make lots of them.
Spring won't know you're wanting to load these as spring beans if you call this constructor directly. So creating these through a factory of some sort would be one way to go. Something like:
#Configuration
public class AgeInputStateFactory {
private #Autowired ClientService clientService;
#Bean
#Scope("prototype") // Makes a new one each time...
public AgeInputState create(final boolean isInputIndeed) {
return new AgeInputState(this.clientService, isInputIndeed);
}
}
Along with a newly designed AgeInputState constructor which also takes the ClientService field.
public class AgeInputState extends AbstractState {
private final ClientService clientService;
// Package private constructor so that no one outside
// of this package will call it. This means you can
// (try your best to) limit the construction to the
// factory class.
AgeInputState(final ClientService clientService,
final boolean isInputIndeed) {
super(isInputIndeed, State.AGE_INPUT);
this.clientService = clientService;
}
}
And then all you would do is wherever you need to create these AgeInputState Objects, you would #Autowire the AgeInputStateFactory instance, and call the create method whenever you need one.

Spring bean scope for "one object per test method"

I have a test utility for with I need to have a fresh instance per test method (to prevent that state leaks between tests). So far, I was using the scope "prototype", but now I want to be able to wire the utility into another test utility, and the wired instances shall be the same per test.
This appears to be a standard problem, so I was wondering if there is a "test method" scope or something similar?
This is the structure of the test class and test utilities:
#RunWith(SpringRunner.class)
#SpringBootTest
public class MyTest {
#Autowired
private TestDriver driver;
#Autowired
private TestStateProvider state;
// ... state
// ... methods
}
#Component
#Scope("prototype") // not right because MyTest and TestStateProvider get separate instances
public class TestDriver {
// ...
}
#Component
public class TestStateProvider {
#Autowired
private TestDriver driver;
// ...
}
I'm aware that I could use #Scope("singleton") and #DirtiesContext(classMode = ClassMode.AFTER_EACH_TEST_METHOD) but this refreshes more than I need – a new TestDriver instance for each test would be enough. Also, this approach is error-prone because all tests using the TestDriver would need to know that they also need the #DirtiesContext annotation. So I'm looking for a better solution.

It is actually pretty easy to implement a testMethod scope:
public class TestMethodScope implements Scope {
public static final String NAME = "testMethod";
private Map<String, Object> scopedObjects = new HashMap<>();
private Map<String, Runnable> destructionCallbacks = new HashMap<>();
#Override
public Object get(String name, ObjectFactory<?> objectFactory) {
if (!scopedObjects.containsKey(name)) {
scopedObjects.put(name, objectFactory.getObject());
}
return scopedObjects.get(name);
}
#Override
public void registerDestructionCallback(String name, Runnable callback) {
destructionCallbacks.put(name, callback);
}
#Override
public Object remove(String name) {
throw new UnsupportedOperationException();
}
#Override
public String getConversationId() {
return null;
}
#Override
public Object resolveContextualObject(String key) {
return null;
}
public static class TestExecutionListener implements org.springframework.test.context.TestExecutionListener {
#Override
public void afterTestMethod(TestContext testContext) throws Exception {
ConfigurableApplicationContext applicationContext = (ConfigurableApplicationContext) testContext
.getApplicationContext();
TestMethodScope scope = (TestMethodScope) applicationContext.getBeanFactory().getRegisteredScope(NAME);
scope.destructionCallbacks.values().forEach(callback -> callback.run());
scope.destructionCallbacks.clear();
scope.scopedObjects.clear();
}
}
#Component
public static class ScopeRegistration implements BeanFactoryPostProcessor {
#Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory factory) throws BeansException {
factory.registerScope(NAME, new TestMethodScope());
}
}
}
Just register the test execution listener, and there will be one instance per test of all #Scope("testMethod") annotated types:
#RunWith(SpringRunner.class)
#SpringBootTest
#TestExecutionListeners(listeners = TestMethodScope.TestExecutionListener.class,
mergeMode = MergeMode.MERGE_WITH_DEFAULTS)
public class MyTest {
#Autowired
// ... types annotated with #Scope("testMethod")
}

I ran into the same problem some time ago and came to this solution:
Use Mocks
I wrote some methods to create specific mockito settings to add behavior to each mock.
So create a TestConfiguration class with following methods and bean definition.
private MockSettings createResetAfterMockSettings() {
return MockReset.withSettings(MockReset.AFTER);
}
private <T> T mockClass(Class<T> classToMock) {
return mock(classToMock, createResetAfterMockSettings());
}
and your bean definition will look like:
#Bean
public TestDriver testDriver() {
return mockClass(TestDriver .class);
}
MockReset.AFTER is used to reset the mock after the test method is run.
And finally add a TestExecutionListeners to your Test class:
#TestExecutionListeners({ResetMocksTestExecutionListener.class})

JMockit : How to inject a MockUp class into a tested class?

I'm new to JMockIt and am trying to figure out/understand how to use #Injectable for a top-level MockUp class that I have already defined.
For example:
// JUnit Test Class
public class RepositoryTest {
#Tested private Repository repository;
#Injectable private ResultsAPIWrapper resultsApiWrapper;
#Test
public void testRepo(){
new ResultsApiWrapper();
assertThat(repository.doSomething(), is("done" ) );
}
}
// Class under test
public class Repository{
#Autowired private ResultsAPIWrapper resultsApiWrapper;
public String doSomething(){
return resultsApiWrapper.load();
}
}
// Mocked implementation of the ResultsAPIWrapper that I want injected into Repository
public class ResultsApiWrapperMock extends MockUp<ResultsAPIWrapper>{
#Mock
public String load(){
return "done";
}
}
If I try the above, I get an error
java.lang.IllegalArgumentException: Class already mocked: com.fw.wrappers.ResultsAPIWrapper
at com.fw.wrappers.mock.ResultsApiWrapperMock.<init>(ResultsApiWrapperMock.java:12)
at com.fw.repository.RepositoryTest.testRepo(RepositoryTest.java:38)
But If I remove the new ResultsApiWrapper() then I do not know how to specify which is the class I want to use as my mocked implementation for the autowire.
Am I misunderstanding how to do this? How can I specify that I want JMockit to autowire using my MockUp<> implementation?

I'm new too but I think something like this would work in your case...
This will mock the ResultsAPIWrapper() and not initialize any static variables and create a specific mock for load():
new MockUp<ResultsAPIWrapper>() {
#Mock
void $clinit() {
//disable static initialization
}
#Mock
public String load() {
return "done";
}
};

#inject doesn't seem to work NPE when injecting an object

I've been struggling with this issue for a while now, so I came here to share it with you.
First I have a class in which I want to inject an Object:
public class MyClass {
#javax.inject.Inject
private MyInterface interface
/.../
public void myMethod(){
interface.doTask();
}
The MyInterface :
public interface MyInterface {
public abstract void doTask() throws Exception;
}
is an interface which I bind to its implementation:
public class MyInterfaceImpl implements MyInterface{
#Inject
public MyInterfaceImpl(...) {
/.../
}
#Override
public void doTask() throws Exception{
/.../
}
in the Config:
public class ApplicationConfig extends ResourceConfig {
private Config config = new Config();
public ApplicationConfig() {
super();
register(new MainBinder());
}
private class MainBinder extends AbstractBinder {
#Override
protected void configure() {
bind(MyInterfaceImpl.class).to(MyInterface.class).in(Singleton.class);
}
}
}
So, when I run the app and try to execute the method I have a NPE on:
interface.doTask();
Voilà, I am sorry to ask but I need some help on that, plus I've tried to be as generic as possible hoping it didn't impact your comprehension.
Edit:
Forgot to mention that the class MyClass() is called in another class like this: new MyClass()
So I think the problem might be there.

So I figure it out!
I was creating a new instance of myClass => new MyClass() thus the injection couldn't work!
So I injected the MyClass() instead of creating a new instance and bound it in the ApplicationConfig.
This worked fine.

Using Jersey's Dependency Injection in a Standalone application

I have a interface here
interface Idemo{
public int getDemo(int i);
}
And it's one implementation
class DemoImpl implements Idemo{
#Override
public int getDemo(int i){
return i+10;
}
}
And there is a class which has a dependency on Idemo
class Sample{
#Inject
Idemo demo;
public int getSample(int i){
return demo.getDemo(i);
}
}
Now say I want to test Sample class
public class SampleTest extends JerseyTest {
#Inject
Sample s;
#Override
protected Application configure() {
AbstractBinder binder = new AbstractBinder() {
#Override
protected void configure() {
bind(Demo.class).to(Idemo.class);
bind(Sample.class).to(Sample.class); //**doesn't work**
}
};
ResourceConfig config = new ResourceConfig(Sample.class);
config.register(binder);
return config;
}
#Test
public void test_getSample() {
assertEquals(15, s.getSample(5)); //null pointer exception
}
}
Here the Sample instance is not getting created and s remains null.I suppose this is because by the time the execution reaches line where binding is specified this test class has already been created.But I am not sure.With Spring Autowired instead of jersey CDI the same works
Had Sample been a resource/controller class the test framework would create an instance of it with no need to inject it but is it possible to test any other non-web class using Jersey DI ?

The reason it works with Spring is that the test class is managed by the Spring container by using #RunWith(SpringJUnit4ClassRunner.class). The runner will inject all managed objects into the test object. JerseyTest is not managed this way.
If you want, you can create your own runner, but you need to understand a bit how HK2 (Jersey's DI framework) works. Take a look at the documentation. Everything revolves around the ServiceLocator. In a standalone, you might see something like this to bootstrap the DI container
ServiceLocatorFactory factory = ServiceLocatorFactory.getInstance();
ServiceLocator locator = factory.create(null);
ServiceLocatorUtilities.bind(locator, new MyBinder());
Then to get the service, do
Service service = locator.getService(Service.class);
In the case of the test class, we don't need to gain any access to the service object, we can simply inject the test object, using the ServiceLocator:
locator.inject(test);
Above, test is the test class instance that gets passed to us in our custom runner. Here is the example implementation of a custom runner
import java.lang.annotation.*;
import org.glassfish.hk2.api.*;
import org.glassfish.hk2.utilities.*;
import org.junit.runners.BlockJUnit4ClassRunner;
import org.junit.runners.model.*;
public class Hk2ClassRunner extends BlockJUnit4ClassRunner {
private final ServiceLocatorFactory factory = ServiceLocatorFactory.getInstance();
private Class<? extends Binder>[] binderClasses;
#Target({ElementType.TYPE})
#Retention(RetentionPolicy.RUNTIME)
public static #interface Binders {
public Class<? extends Binder>[] value();
}
public Hk2ClassRunner(Class<?> cls) throws InitializationError {
super(cls);
Binders bindersAnno = cls.getClass().getAnnotation(Binders.class);
if (bindersAnno == null) {
binderClasses = new Class[0];
}
}
#Override
public Statement methodInvoker(FrameworkMethod method, final Object test) {
final Statement statement = super.methodInvoker(method, test);
return new Statement() {
#Override
public void evaluate() throws Throwable {
ServiceLocator locator = factory.create(null);
for (Class<? extends Binder> c : binderClasses) {
try {
ServiceLocatorUtilities.bind(locator, c.newInstance());
} catch (InstantiationException | IllegalAccessException ex) {
throw new RuntimeException(ex);
}
}
locator.inject(test);
statement.evaluate();
locator.shutdown();
}
};
}
}
In the runner, the methodInvoker is called for every test method, so we are creating a fresh new set of objects for each test method called.
Here is a complete test case
#Binders({ServiceBinder.class})
#RunWith(Hk2ClassRunner.class)
public class InjectTest {
public static class Service {
#Inject
private Demo demo;
public void doSomething() {
System.out.println("Inside Service.doSomething()");
demo.doSomething();
}
}
public static class Demo {
public void doSomething() {
System.out.println("Inside Demo.doSomething()");
}
}
public static class ServiceBinder extends AbstractBinder {
#Override
protected void configure() {
bind(Demo.class).to(Demo.class);
bind(Service.class).to(Service.class);
}
}
#Inject
private Service service;
#Test
public void testInjections() {
Assert.assertNotNull(service);
service.doSomething();
}
}

I was facing the same situation but in the context of running some integrations test that needs to have some of the singletons that my application have already defined.
The trick that I found is the following. You just need to create a normal test class or a standalone that use the DropwizardAppRule
In my case, I use JUnit as I was writing some integration test.
public class MyIntegrationTest{
//CONFIG_PATH is just a string that reference to your yaml.file
#ClassRule
public static final DropwizardAppRule<XXXConfiguration> APP_RULE =
new DropwizardAppRule<>(XXXApplication.class, CONFIG_PATH);
}
The #ClassRule will start your application like is said here . That
means you will have access to everything and every object your application needs to start. In my case, I need to get access to a singleton for my service I do that using the #Inject annotation and the #Named
public class MyIntegrationTest {
#ClassRule
public static final DropwizardAppRule<XXXConfiguration> APP_RULE =
new DropwizardAppRule<>(XXXAplication.class, CONFIG_PATH);
#Inject
#Named("myService")
private ServiceImpl myService;
}
Running this will set to null the service as #Inject is not working because we don't have at this point anything that put the beans into the references. There is where this method comes handy.
#Before
public void setup() {
ServiceLocator serviceLocator =((ServletContainer)APP_RULE.getEnvironment().getJerseyServletContainer()).getApplicationHandler().getServiceLocator();
//This line will take the beans from the locator and inject them in their
//reference, so each #Inject reference will be populated.
serviceLocator.inject(this);
}
That will avoid creating other binders and configurations outside of the existing on your application.
Reference to the ServiceLocator that DropwizardAppRule creates can be found here