Backport of JSR 166: Technical principles in the Java class library
JSR 166's back movement: technical principles in the Java class library
Overview:
JSR 166 (Java specification 166) is a series of concurrent tools and class libraries defined in the Java language specification.It provides many advanced functions of operations, control and management in multi -threaded environments.Although the JSR 166 was originally introduced to the Java SE 5, some characteristics were moved backwards in the earlier versions so that they can achieve the same concurrency function in the older Java version.This article will introduce the principle of back -shift technology of JSR 166 and use the Java code example.
Technical principle:
The back movement of the JSR 166 is achieved through the old Java version of concurrent class and tools, imitating the characteristics and behavior in JSR 166.This process usually involves reverse engineering on concurrent tools and class libraries to provide similar functions in the older Java version.
Specific steps:
1. Study JSR 166: First of all, you need to carefully study the concurrent tools and class libraries in JSR 166 to understand its functions and implementation details.This will help simulate similar behavior in the older Java version.
2. Analyze the differences in the Java version: Through the detailed understanding of the difference between the Java version and the Java version supported by the JAVA version and the JSR 166, determine the function and class library that needs to be moved.
3. Reverse engineering: According to the research and analysis of the JSR 166, use the characteristics, interfaces, and classes provided by the target Java version to achieve corresponding classes and tools.This involves the functions provided by the target Java version, and redesigned and developed new classes and tools to simulate the behavior of JSR 166.
4. Test and verification: Write test cases for the new post -moving library and tools, and ensure that it is consistent with the characteristics and behaviors of the JSR 166.Perform comprehensive testing and verification to ensure the correctness and reliability of the class libraries and tools.
Example code:
Below is a simple sample code to demonstrate a common rear movement technology
import java.util.concurrent.TimeUnit;
public class CountDownLatch {
private int count;
public CountDownLatch(int count) {
this.count = count;
}
public synchronized void await() throws InterruptedException {
while (count > 0) {
wait();
}
}
public synchronized void countDown() {
if (count > 0) {
count--;
if (count == 0) {
notifyAll();
}
}
}
// Example usage
public static void main(String[] args) throws InterruptedException {
CountDownLatch latch = new CountDownLatch(3);
Thread worker1 = new Thread(() -> {
try {
TimeUnit.SECONDS.sleep(2);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("Worker 1 completed");
latch.countDown();
});
Thread worker2 = new Thread(() -> {
try {
TimeUnit.SECONDS.sleep(3);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("Worker 2 completed");
latch.countDown();
});
Thread worker3 = new Thread(() -> {
try {
TimeUnit.SECONDS.sleep(1);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("Worker 3 completed");
latch.countDown();
});
worker1.start();
worker2.start();
worker3.start();
latch.await();
System.out.println("All workers completed");
}
}
The above code demonstrates the simple implementation of a custom COUNTDOWLATCH class.This class is used to wait for a set of threads to complete the specific task before continuing.By calling the countdown () method to represent the task of each thread, call the AWAIT () method to wait for all tasks to complete.
in conclusion:
The rear -shift technology of JSR 166 provides the older Java version with a concurrent function similar to the JSR 166.Through reverse engineering and reorganization, Java developers can use the advanced concurrent library and tools of JSR 166 in the early Java versions.This provides more options for developing multi -threaded applications and allows more powerful concurrent control in the older Java environment.
