Google Guice binding using Annotation and Key class - binding

Lets say we have A.java interface implemented by AImpl.java and B.java implemented by Bimpl.java
Above classes are binded in two modules as below
Module1 {
bind(A.class).to(AImpl.class);
bind(B.class).to(BImpl.class);
}
Module2 {
Key<A> aKey = Key.get(A.class, AnAnnot.class);
bind(aKey).to(AImpl.class);
Key<B> bKey = Key.get(B.class, AnAnnot.class);
bind(bKey).to(BImpl.class);
}
Class AImpl implements A {
}
Class BImpl implements B {
#Inject
BImpl(A aImpl) {
//??
}
}
BImpl refers to A
For BImpl binded using Annotation, I want corresponding aImpl, binded using Annotation but here I'm getting aImpl which is not binded using Annotation
Please suggest

I'm able to achieve using below pattern. May be there is a more easier way. Happy to know more
A.java
public interface A {
String aMethod();
}
AImpl.java
public class AImpl implements A {
private String moduleName;
public AImpl(String moduleName) {
this.moduleName = moduleName;
}
#Override
public String aMethod() {
return moduleName;
}
}
B.java
public interface B {
String bMethod();
}
Bimpl.java
public class BImpl implements B {
private final A a;
BImpl(A a) {
this.a = a;
}
#Override
public String bMethod() {
return a.aMethod();
}
}
AnAnnot.java
#Target(PARAMETER)
#Retention(RUNTIME)
#BindingAnnotation
public #interface AnAnnot {
}
BProvider.java
public class BProvider implements Provider<B> {
private final A a;
#Inject
BProvider(A a) {
this.a = a;
}
#Override
public B get() {
return new BImpl(a);
}
}
BHavingAnnotatedA.java
public class BHavingAnnotatedA implements Provider<B> {
private final A a;
#Inject
BHavingAnnotatedA(#AnAnnot A a) {
this.a = a;
}
#Override
public B get() {
return new BImpl(a);
}
}
ABModule1.java
public class ABModule1 extends AbstractModule {
#Override
protected void configure() {
bind(A.class).to(AImpl.class);
bind(B.class).toProvider(BProvider.class);
}
}
ABModule2.java
public class ABModule2 extends AbstractModule {
#Override
protected void configure() {
Key<A> aKey = Key.get(A.class, AnAnnot.class);
bind(aKey).to(AImpl.class);
Key<B> bKey = Key.get(B.class, AnAnnot.class);
bind(bKey).toProvider(BHavingAnnotatedA.class);
}
}

Related

How can I inject Optional<T> with hk2?

I have a Factory that looks at some property to determine if the value T should be provided. How can I use this with HK2 in an abstract binder?
public interface Printer {
void print(String str);
}
public ConsolePrinter implements Printer {
public void print(String str) {
System.out.println(str);
}
}
public PrinterFactory implements Factory<Optional<Printer>> {
boolean isPrinterAvailable;
public PrinterFactory(boolean isPrinterAvailable) {
this.isPrinterAvailable = isPrinterAvailable;
}
public Optional<Printer> provide() {
if (this.isPrinterAvailable) {
return new ConsolePrinter();
}
return Optional.empty();
}
}
public class Binder extends AbstractBinder {
protected void configure() {
// ?????
bindFactory(PrinterFactory.class).to(Printer.class);
}
}
Any help/documentation/examples is much appreciated!

Dagger generated code compilation failed when using #Singleton annotation

I am using Dagger - 2.6 and i have the following classes.
public class Trigger {
public static JSONObject triggerLambda(JSONObject jsonObject) {
DataTransformerComponent daggerDataTransformerComponent = DaggerDataTransformerComponent.create();
return daggerDataTransformerComponent.getHandler().handle(jsonObject);
}
}
Data Handler class:
public class DataHandler {
private static final Logger LOGGER = Logger.getLogger(DataHandler.class.getName());
private A a;
#Inject
public DataHandler(A a) {
this.a = a;
}
public JSONObject handle(JSONObject input) {
LOGGER.info("Json input received - " + input.toString());
return a.executeTransformation(input);
}
}
And a dependency:
public class A {
#Inject
public A() {
}
public JSONObject executeTransformation(JSONObject jsonObject) {
System.out.println("a");
return null;
}
}
My component class looks like:
#Component
public interface DataTransformerComponent {
DataHandler getHandler();
}
When i compile the above code it runs absolutely fine.
Now i want to make my A dependency #Singleton.
So i change my dependency class and component class as follows:
#Singleton
#Component
public interface DataTransformerComponent {
DataHandler getHandler();
}
Dependency class:
#Singleton
public class A {
#Inject
public A() {
}
public JSONObject executeTransformation(JSONObject jsonObject) {
System.out.println("a");
return null;
}
}
But now the generated component shows compilation errors saying:
A_Factory not found and it fails in the initialize() method.
DaggerDataTransformerComponent :
#Generated(
value = "dagger.internal.codegen.ComponentProcessor",
comments = "https://google.github.io/dagger"
)
public final class DaggerDataTransformerComponent implements DataTransformerComponent {
private Provider<A> aProvider;
private Provider<DataHandler> dataHandlerProvider;
private DaggerDataTransformerComponent(Builder builder) {
assert builder != null;
initialize(builder);
}
public static Builder builder() {
return new Builder();
}
public static DataTransformerComponent create() {
return builder().build();
}
#SuppressWarnings("unchecked")
private void initialize(final Builder builder) {
this.aProvider = DoubleCheck.provider(A_Factory.create());
this.dataHandlerProvider = DataHandler_Factory.create(aProvider);
}
#Override
public DataHandler getHandler() {
return dataHandlerProvider.get();
}
public static final class Builder {
private Builder() {}
public DataTransformerComponent build() {
return new DaggerDataTransformerComponent(this);
}
}
}
I am unable to figure out why it does not create _factory class when i use #Singleton annotation.?.
Just use regular JavaScript + node.js, its a lot simpler

StructureMap - DI - Multiple Concrete Implementation

I have referred multiple threads for solution but those did not help :( Any help to provide solution in terms of code on below problem is appreciated
class Program
{
static void Main(string[] args)
{
//StructureMapConfiguration();
var registry = new Registry();
registry.IncludeRegistry<DependencyRegistry>();
var container = new Container(registry);
var depend = container.GetInstance<ITest>();
var controller1 = new Controller1(depend);
controller1.M1();
var controller2 = new Controller2(depend);
controller1.M1();
Console.Read();
}
}
public interface ITest
{
void Method();
}
public class A : ITest
{
public void Method()
{
Console.WriteLine("A");
}
}
public class B : ITest
{
public void Method()
{
Console.WriteLine("B");
}
}
public class C : ITest
{
public void Method()
{
Console.WriteLine("C");
}
}
public interface IController
{
void M1();
}
public class Controller1 : IController
{
private ITest _test;
public Controller1()
{
}
public Controller1(ITest test)
{
_test = test;
}
public void M1()
{
_test.Method();
}
}
public class Controller2 : IController
{
private ITest _test;
public Controller2(ITest test)
{
_test = test;
}
public void M1()
{
_test.Method();
}
}
public class DependencyRegistry : Registry
{
public DependencyRegistry()
{
For<ITest>().Use<A>().Named("A");
For<ITest>().Use<B>().Named("B");
For<ITest>().Use<C>().Named("C");
For<IController>().Add<Controller1>().Ctor<ITest>().Is(i => i.GetInstance<ITest>("A"));
For<IController>().Add<Controller2>().Ctor<ITest>().Is(i => i.GetInstance<ITest>("B"));
Scan(x =>
{
x.AssembliesFromApplicationBaseDirectory();
x.AddAllTypesOf<ITest>().NameBy(type => type.Name);
x.WithDefaultConventions();
});
}
}
}
Actual Result:
Everytime I am getting instance of class C for Controller1 and Controller2
Expected Result:
For Controller1, I need instance of class A and for Controller2, I need instance of class B
Thanks in advance

Jersy2 inject slf4j Logger

I'm trying to understand Jersey 2 development and context-dependency injection.
I don't understand how to inject into a resource an object that needs initialization parameters in the constructor.
For example: I'd like to #Inject slf4j Logger, built using LoggerFactory.
My resource class is:
#Path("/myresource")
public class MyResource {
#Inject
private Logger log;
#GET
#Produces(MediaType.APPLICATION_JSON)
public Answer status() {
log.info("STATUS");
return new Answer(200, "Server up and running # "+ ZonedDateTime.now());
}
}
My Resource config is:
public class MyAppextends ResourceConfig {
public MyApp() {
register(new MyBinder());
packages(true, "my.packages");
}
}
public class MyBinder extends AbstractBinder {
#Override
protected void configure() {
bindFactory(MyLoggerFactory.class).to(org.slf4j.Logger.class);
}
}
Finally, the Factory is:
public class MyLoggerFactory implements Factory<Logger> {
#Override
public Logger provide() {
return LoggerFactory.getLogger(TYPE_FOR_LOGGING.class);
}
#Override
public void dispose(Logger logger) {
}
}
How can I specify TYPE_FOR_LOGGING as argument, in order to Inject the correctly initialized Logger in every resource I want?
Thanks
What you are looking for is called the InstantiationService. You can inject it into Factories to find out who is calling the factory inside of the provide method.
Below find a code sample from the hk2 tests that illustrate the use of the InstantiationService.
#Singleton
public class CorrelationFactory implements Factory<PerLookupServiceWithName> {
private final static PerLookupServiceWithName NULL_SERVICE = new PerLookupServiceWithName() {
#Override
public String getName() {
return null;
}
};
#Inject
private InstantiationService instantiationService;
/* (non-Javadoc)
* #see org.glassfish.hk2.api.Factory#provide()
*/
#Override #PerLookup
public PerLookupServiceWithName provide() {
InstantiationData data = instantiationService.getInstantiationData();
if (data == null) {
return NULL_SERVICE;
}
Injectee parent = data.getParentInjectee();
if (parent == null) {
return NULL_SERVICE;
}
Class<?> parentClass = parent.getInjecteeClass();
if (parentClass == null) {
return NULL_SERVICE;
}
Correlator correlator = parentClass.getAnnotation(Correlator.class);
if (correlator == null) {
return NULL_SERVICE;
}
final String fName = correlator.value();
return new PerLookupServiceWithName() {
#Override
public String getName() {
return fName;
}
};
}
/* (non-Javadoc)
* #see org.glassfish.hk2.api.Factory#dispose(java.lang.Object)
*/
#Override
public void dispose(PerLookupServiceWithName instance) {
// DO nothing
}
}

Autofac. How to get caller class Type?

Suppose we have two classes with same constructor Injectable dependency:
public class FirstClass
{
public FirstClass(ISomeDependency someDependency)
{ }
}
public class SecondClass
{
public SecondClass(ISomeDependency someDependency)
{ }
}
Now we have a registration for ISomeDependency:
builder.Register(x =>
{
string key = GetKeyFromCurrentHttpRequest();
// if "Caller" is "FirstClass" return new Dependency(key);
// else return new Dependency("defaultKey");
}).As<ISomeDependency>();
Note: This is a simplified use case. The real scenario is much more complicated.
1. How to get "Caller" type which tryies to resolve ISomeDependency?
2. Is there a better way design for such situations?
You can use delegate factories do achieve your goal. The only drawback is the FirstClass and SecondClass cannot use ISomeDependency as parameter.
You can try this code in a console application (just add Autofac dependency).
using System;
using Autofac;
namespace test
{
class MainClass
{
public static void Main(string[] args)
{
ContainerBuilder builder = new ContainerBuilder ();
builder.RegisterType<SomeDependency>().As<ISomeDependency>();
builder.RegisterType<FirstClass>();
builder.RegisterType<SecondClass>();
var container = builder.Build();
var dummy = container.Resolve<FirstClass>();
var dummy2 = container.Resolve<SecondClass>();
}
public interface ISomeDependency
{
}
public class SomeDependency : ISomeDependency
{
public delegate ISomeDependency Factory(string value);
private readonly string _value;
public SomeDependency(string value)
{
_value = value;
Console.WriteLine("Value = " + _value);
}
}
public class FirstClass
{
private ISomeDependency _dependency;
public FirstClass(SomeDependency.Factory factory)
{
_dependency = factory.Invoke("my value");
}
}
public class SecondClass
{
private ISomeDependency _dependency;
public SecondClass(SomeDependency.Factory factory)
{
_dependency = factory.Invoke("my value 2");
}
}
}
}

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