Analyze the technical principles and design ideas of the Javax Inject TCK framework in the Java class library
Javax Inject (that is, JSR 330) is a standard specification in the Java class library to rely on injection. This specification defines a set of annotations and interfaces to help developers realize the dependent relationship between loose coupling classes.Among them, the TCK (Technolog Composition Kit) framework is part of the Javax Inject, which is used to test whether each implementation version meets the specification requirements.This article will analyze the technical principles and design ideas of the Javax Inject TCK framework.
1. Technical principle:
The implementation principle of the Javax Inject TCK framework is based on reflection and Dynamic Proxy technology.Through reflection, the TCK framework can detect the class that has been loaded in the virtual machine, identify annotations, and create proxy objects for these classes through a dynamic proxy mechanism.
2. Design ideas:
2.1 Definition test case: The TCK framework is defined by defining a series of test cases to verify whether the dependencies are injecting whether to meet the standard specifications.Test cases cover the correct use of annotations, type verification in injection dependencies, and life cycle management.
2.2 Reflex scanning: The TCK framework will scan the entire class path and use reflex technology to identify and load the category of the annotation marked.These classes can be Bean, Provider, Qualifier, Scope, etc.
2.3 Dynamic proxy: The TCK framework will use a dynamic proxy mechanism to create proxy objects markedly marked.Through dynamic proxy, the TCK framework can intercept the method of calling the proxy object during runtime and inject relevant dependencies.
2.4 Injecting verification: The TCK framework will verify the dependent injection behavior at runtime to ensure that the requirements of the relevant specifications are met.For example, the TCK framework will check whether it meets the uniqueness of the injection, the management of the scope, and the type matching.
Below is an example code that uses the Javax Inject TCK framework:
import javax.inject.Inject;
public class MyApp {
@Inject
private MyService myService;
public void doSomething() {
myService.doTask();
}
}
public interface MyService {
void doTask();
}
public class MyServiceImpl implements MyService {
@Override
public void doTask() {
System.out.println("Doing task...");
}
}
public class Main {
public static void main(String[] args) {
MyApp app = new MyApp();
MyService myService = new MyServiceImpl();
// Use the TCK framework for myService object for dependent injection
TckFramework.injectDependencies(myService);
app.doSomething();
}
}
In the above examples, the `MyApp` class depends on the` MyService` interface, and use the@inject` annotation to inject the implementation class `myServiceImpl` into the` myService` field.By using the TCK framework's `InjectDependenCies` method, we can rely on the relying injection of the` MyService` object at runtime.
Through the Javax Inject TCK framework, we can achieve flexible dependency injection in the Java class library to improve the maintenance of code and testability.Using the TCK framework, we can ensure that the compatibility of various dependent injection frameworks and ensure that it meets the standards and specifications.
