Use Autoservice Processor framework to implement automatic services in the Java class library to load
Use Autoservice Processor framework to implement automatic services in the Java class library to load
Overview:
The automatic service loading in the Java class library is a common design mode that allows developers to easily expand the function of the application.Autoservice Processor framework is a tool developed by Google. It provides a simple and powerful method for automatic service loading.This article will introduce the principles and usage methods of Autoservice Processor framework and some Java code examples.
Autoservice Processor framework principle:
Autoservice Processor framework is based on the Java annotation processor mechanism.It automatically generates the implementation code of the service loader by scanning the class file and annotation information in the Java path.When the application is running, the service loader will automatically load and instantiate the service provider.
Steps to use Autoservice Processor framework:
1. Define the service interface in the Java class library: The service interface is a set of interfaces that define the required functions, and the method that service providers must implement.
public interface MyService {
void doSomething();
}
2. Create service provider (Service Provider): Service providers are specific classes for the service interface.
@AutoService(MyService.class)
public class MyServiceProvider implements MyService {
public void doSomething() {
// Implement specific functions
}
}
3. Use Autoservice Note: Use the@Autoservice` annotation on the service provider class to specify the service interface implemented.
4. Generate service loader: When constructing a project, the Autoservice Processor framework will automatically scan the class with the annotation of `@Autoservice`, and then generate the implementation class of the service loader.
public final class MyServiceLoader {
public static <S> List<S> load(Class<S> service) {
// Load and instantiated service providers, and return to the list of service objects
}
}
5. Load and use services: Use `myServiceLoader.load ()` method in the application to load the service provider and obtain service objects.
List<MyService> services = MyServiceLoader.load(MyService.class);
for (MyService service : services) {
service.doSomething();
}
Summarize:
Autoservice Processor framework provides a simple and efficient way to achieve automatic service loading in the Java class library.Through the annotations of the provider service provider class, developers can easily expand the function of the application.Using the Autoservice Processor framework, the instance and loading process of the service provider are completely processed by the framework, making the application development more convenient and flexible.
Java code example:
import com.google.auto.service.AutoService;
public interface MyService {
void doSomething();
}
@AutoService(MyService.class)
public class MyServiceProvider implements MyService {
public void doSomething() {
System.out.println("Doing something...");
}
}
public final class MyServiceLoader {
public static <S> List<S> load(Class<S> service) {
List<S> services = new ArrayList<>();
ServiceLoader.load(service).forEach(services::add);
return services;
}
}
public class Main {
public static void main(String[] args) {
List<MyService> services = MyServiceLoader.load(MyService.class);
for (MyService service : services) {
service.doSomething();
}
}
}
