可以通过使用BlockingQueue来实现MemorySegment在多个线程之间的可见性。下面是一个示例代码:
import java.nio.ByteBuffer;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
public class MemorySegmentExample {
private static final int MAX_ELEMENTS = 10;
private static final int ELEMENT_SIZE = 4; // bytes per integer
private static final Path MEMORY_FILE = Paths.get("/tmp/memory");
public static void main(String[] args) throws Exception {
BlockingQueue queue = new ArrayBlockingQueue<>(MAX_ELEMENTS);
// initialize the memory file with zeros
byte[] zeros = new byte[ELEMENT_SIZE * MAX_ELEMENTS];
Files.write(MEMORY_FILE, zeros);
// start two threads: a writer and a reader
Thread writer = new Thread(() -> {
try {
ByteBuffer buffer = ByteBuffer.wrap(Files.readAllBytes(MEMORY_FILE));
for (int i = 0; i < MAX_ELEMENTS; i++) {
buffer.putInt(ELEMENT_SIZE * i, i);
queue.put(buffer);
buffer = ByteBuffer.wrap(Files.readAllBytes(MEMORY_FILE));
}
} catch (Exception e) {
e.printStackTrace();
}
});
Thread reader = new Thread(() -> {
try {
int sum = 0;
for (int i = 0; i < MAX_ELEMENTS; i++) {
ByteBuffer buffer = queue.take();
int element = buffer.getInt(ELEMENT_SIZE * i);
sum += element;
}
System.out.println("Sum: " + sum);
} catch (Exception e) {
e.printStackTrace();
}
});
writer.start();
reader.start();
writer.join();
reader.join();
}
}
在此示例中,我们使用一个BlockingQueue来传输ByteBuffer对象,其中每个元素都包含一个整数。写线程首先打开一个文件,然后从中读取整个ByteBuffer,并将每个元素设置为其索引。然后,它将该ByteBuffer放入BlockingQueue中以便读线程可以使用。读线程从BlockingQueue中获取每个ByteBuffer并读取其包含的整数之一。最终,它计算所有整数的总和并打印结果。
通过使用BlockingQueue,我们确保读线程只读取正在被写线程修改的ByteBuffer,因此所有线程都使用相同的MemorySegment,并且对其进行了同步。
上一篇:BlockingQueueadd()在Java中的例子
下一篇:BlockingQueue失去引用并在JettyWebSocketonMessage上抛出NullPointerException