In concurrent programming, data exchange between threads is a common operation. The Exchanger class in Java's Concurrent API provides a mechanism for threads to exchange data in a safe and convenient way.
This article will give an overview of the Exchanger class and demonstrate how it can be used in a concurrent program.
The Exchanger class is a utility class for exchanging data between threads. It provides a single method, exchange(), which takes two arguments: the data to be exchanged, and a timeout value.
If there is another thread waiting to exchange data, the exchange() method will return immediately with the data from the other thread. If there is no other thread waiting, the exchange() method will block until another thread calls exchange() with the same data.
The Exchanger class is useful for situations where two threads need to synchronize their data, such as in a producer-consumer relationship.
Here is a simple example of how the Exchanger class can be used. In this example, two threads are used to exchange data. The first thread generates a random number, and the second thread calculates the square of that number.
import java.util.concurrent.Exchanger;
public class ExchangerExample {
public static void main(String[] args) {
Exchanger<Integer> exchanger = new Exchanger<>();
new Thread(() -> {
try {
int data = (int) (Math.random() * 100);
System.out.println("Thread 1: " + data);
data = exchanger.exchange(data);
System.out.println("Thread 1: " + data);
} catch (InterruptedException e) {
e.printStackTrace();
}
}).start();
new Thread(() -> {
try {
int data = (int) (Math.random() * 100);
System.out.println("Thread 2: " + data);
data = exchanger.exchange(data);
System.out.println("Thread 2: " + data);
} catch (InterruptedException e) {
e.printStackTrace();
}
}).start();
}
}
In this example, the two threads exchange data and then print the results. The output of this program might look something like this:
Thread 1: 97
Thread 2: 25
Thread 1: 625
Thread 2: 676
The Exchanger class provides a mechanism for threads to exchange data in a safe and convenient way. It is useful for situations where two threads need to synchronize their data.