[英]Confused about how to use exchanger in java
與基本上每個交換器任務一樣,我讓生產者填充一個空的buffer2,由消費者清除一個完整的buffer1,當每個線程完成后,他們應該交換各自的緩沖區。
我真的不確定在哪里以及如何申請交易所。 我將readyconsumer和readyproducer定義為布爾值,以便第三個線程可以檢查是否在兩個都成立時就交換緩沖區。 這應該可以解決我用兩個線程執行的問題,其中程序在wait()處被兩個線程卡住了(不幸的是,現在仍然如此)。
這是當前代碼的樣子。 誰能幫助我在哪個班級以及在代碼的什么時候進行交流? 提前非常感謝您!
class Buffer {
static boolean readyconsumer, readyproducer = false;
volatile int count; // number of put actions
static int max = 10;
Buffer() {
count = 0;
}
public synchronized void put() {
if (count == max) {
readyproducer = true;
System.out.println(" wait ");
try {
wait();
} catch (InterruptedException e) {
}
}
count++;
System.out.println("put " + count);
notifyAll();
}
public synchronized void get() {
if (count == 0) {
readyconsumer = true;
System.out.println(" wait");
try {
wait();
} catch (InterruptedException e) {
}
}
count--;
System.out.println("get " + count);
notifyAll();
}
}
class CheckandSwitch extends ProdCon {
public void run() {
while (true) {
if (Buffer.readyconsumer && Buffer.readyproducer) {
try {
ProdCon.buffer2 = exchanger.exchange(ProdCon.buffer1);
ProdCon.buffer1 = exchanger.exchange(ProdCon.buffer2);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Buffer.readyconsumer = false;
Buffer.readyproducer = false;
buffer1.count = 0;
buffer2.count = 10;
notifyAll();
}
}
}
}
class Consumer extends ProdCon {
static Buffer buffer;
Consumer(Buffer b) {
super();
buffer = b;
b.count = 10;
}
public void run() {
while (true) {
consume();
buffer.get();
}
}
private void consume() {
System.out.println("consume");
try {
Thread.sleep(200);
} catch (InterruptedException e) {
}
}
}
class Producer extends ProdCon {
static Buffer buffer;
Producer(Buffer b) {
super();
buffer = b;
b.count = 0;
}
public void run() {
while (true) {
produce();
buffer.put();
}
}
private void produce() {
System.out.println("produce ");
try {
Thread.sleep(50);
} catch (InterruptedException e) {
}
}
}
import java.util.concurrent.*;
public class ProdCon extends Thread {
static Exchanger<Buffer> exchanger = new Exchanger<Buffer>();
static Buffer buffer1, buffer2 = null;
public static void main(String[] args) {
buffer1 = new Buffer();
buffer2 = new Buffer();
new Consumer(buffer1).start();
new Producer(buffer2).start();
new CheckandSwitch().start();
}
}
您可以使用Exchanger 。
這是將Javadoc中的代碼調整為一個工作示例。
class DataBuffer<T> {
T data = null;
public boolean isFull() {
return data != null;
}
public boolean isEmpty() {
return data == null;
}
public T get() {
T d = data;
data = null;
return d;
}
public void put(T data) {
this.data = data;
}
}
class FillAndEmpty {
Exchanger<DataBuffer<Integer>> exchanger = new Exchanger<>();
DataBuffer<Integer> initialEmptyBuffer = new DataBuffer<>();
DataBuffer<Integer> initialFullBuffer = new DataBuffer<>();
int countDown = 10;
class FillingLoop implements Runnable {
@Override
public void run() {
DataBuffer currentBuffer = initialEmptyBuffer;
try {
while (currentBuffer != null && countDown > 0) {
addToBuffer(currentBuffer);
if (currentBuffer.isFull()) {
currentBuffer = exchanger.exchange(currentBuffer);
}
}
} catch (InterruptedException ex) {
}
}
private void addToBuffer(DataBuffer<Integer> currentBuffer) {
currentBuffer.put(countDown--);
}
}
class EmptyingLoop implements Runnable {
@Override
public void run() {
DataBuffer<Integer> currentBuffer = initialFullBuffer;
try {
while (currentBuffer != null) {
takeFromBuffer(currentBuffer);
if (currentBuffer.isEmpty()) {
currentBuffer = exchanger.exchange(currentBuffer);
}
}
} catch (InterruptedException ex) {
}
}
private void takeFromBuffer(DataBuffer<Integer> currentBuffer) {
System.out.println(currentBuffer.get());
}
}
void start() {
new Thread(new FillingLoop()).start();
new Thread(new EmptyingLoop()).start();
}
}
public void test() {
System.out.println("Hello");
new FillAndEmpty().start();
}
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