问题
I have this code.
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
public class SyncProt0 {
public static void main(String... args) {
ExecutorService executorService = Executors.newCachedThreadPool();
ProcessStep psWorker = new ProcessStep();
ProcessStep psBoss = new ProcessStep();
Worker worker = new Worker(executorService, psWorker, psBoss);
Boss boss = new Boss(executorService, psBoss, psWorker);
}
public static class Worker implements Runnable {
private final ProcessStep psWorker;
private final ProcessStep psBoss;
public Worker(ExecutorService executorService, ProcessStep psWorker, ProcessStep psBoss) {
this.psWorker = psWorker;
this.psBoss = psBoss;
executorService.submit(this);
}
@Override
public void run() {
System.out.println("I'm -> Worker. I wait until Boss can see me!");
while (!psBoss.isRunning()) {
try {
Thread.sleep(100);
} catch (Exception e) { }
}
System.out.println("I'm -> Worker. Boss is seeing to me!");
int counter = 0;
while (counter < 6) {
psWorker.setRunning(true);
System.out.println("I'm Working ...");
try {
Thread.sleep(1000);
} catch (Exception e) { }
counter++;
}
psWorker.setRunning(false);
psWorker.setFinished(true);
System.out.println("I'm -> Worker. I left to work!");
}
}
public static class Boss implements Runnable {
private final ProcessStep psBoss;
private final ProcessStep psWorker;
private boolean running;
public Boss(ExecutorService executorService, ProcessStep psBoss, ProcessStep psWorker) {
this.psBoss = psBoss;
this.psWorker = psWorker;
executorService.submit(() -> {
System.out.println("Boss. I have Runnable for turn of me when is needed");
while (!this.psWorker.isFinished()) {
try {
Thread.sleep(100);
} catch (InterruptedException e) { }
}
this.running = false;
});
executorService.submit(this);
}
@Override
public void run() {
System.out.println("I'm -> Boss. I'm delayed 4 Secs");
try {
Thread.sleep(4000);
} catch (Exception e) { }
System.out.println("I'm -> Boss. Let's go to check the work!");
psBoss.setRunning(true);
running = true;
while (running) {
System.out.println("I'm Checking ...");
try {
Thread.sleep(1000);
} catch (Exception e) { }
}
psBoss.setRunning(false);
psBoss.setFinished(true);
System.out.println("I'm -> Boss The work end!");
}
}
public static class ProcessStep {
private final ReadWriteLock rwLock;
private Boolean running;
private Boolean finished;
public ProcessStep() {
this.rwLock = new ReentrantReadWriteLock();
running = false;
finished = false;
}
public Boolean isRunning() {
Lock readLock = rwLock.readLock();
readLock.lock();
try {
return running;
} finally {
readLock.unlock();
}
}
public void setRunning(Boolean running) {
Lock writeLock = rwLock.writeLock();
writeLock.lock();
try {
this.running = running;
} finally {
writeLock.unlock();
}
}
public Boolean isFinished() {
Lock readLock = rwLock.readLock();
readLock.lock();
try {
return finished;
} finally {
readLock.unlock();
}
}
public void setFinished(Boolean finished) {
Lock writeLock = rwLock.writeLock();
writeLock.lock();
try {
this.finished = finished;
} finally {
writeLock.unlock();
}
}
}
}
The output properly is:
I'm -> Worker. I wait until Boss can see me!
Boss. I have Runnable for turn of me when is needed
I'm -> Boss. I'm delayed 4 Secs
I'm -> Boss. Let's go to check the work!
I'm Checking ...
I'm -> Worker. Boss is seeing to me!
I'm Working ...
I'm Checking ...
I'm Working ...
I'm Checking ...
I'm Working ...
I'm Checking ...
I'm Working ...
I'm Checking ...
I'm Working ...
I'm Checking ...
I'm Working ...
I'm Checking ...
I'm -> Worker. I left to work!
I'm -> Boss The work end!
Works fine!
NOTE: I don't want to block all ProcessStep only some property on demand!
I want to use Wait and Notify mechanism over the property changing this code (in Boss class):
while (!this.psWorker.isFinished()) {
try {
Thread.sleep(100);
} catch (InterruptedException e) {
}
}
and this code (in Worker class)
while (!psBoss.isRunning()) {
try {
Thread.sleep(100);
} catch (Exception e) {
}
}
When I changed the Worker and Boss classes with this code:
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
public class SyncProt1 {
public static void main(String... args) {
ExecutorService executorService = Executors.newCachedThreadPool();
ProcessStep psWorker = new ProcessStep();
ProcessStep psBoss = new ProcessStep();
Worker worker = new Worker(executorService, psWorker, psBoss);
Boss boss = new Boss(executorService, psBoss, psWorker);
}
public static class Worker implements Runnable {
private final ProcessStep psWorker;
private final ProcessStep psBoss;
public Worker(ExecutorService executorService, ProcessStep psWorker, ProcessStep psBoss) {
this.psWorker = psWorker;
this.psBoss = psBoss;
executorService.submit(this);
}
@Override
public void run() {
System.out.println("I'm -> Worker. I wait until Boss can see me!");
synchronized (this.psBoss.isRunning()) {
try {
psBoss.isRunning().wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("I'm -> Worker. Boss is seeing to me!");
int counter = 0;
while (counter < 6) {
synchronized (this.psWorker.isRunning()) {
psWorker.setRunning(true);
psWorker.isRunning().notify();
}
System.out.println("I'm Working ...");
try {
Thread.sleep(1000);
} catch (Exception e) { }
counter++;
}
synchronized (this.psWorker.isRunning()) {
psWorker.setRunning(false);
psWorker.isRunning().notify();
}
synchronized (this.psWorker.isFinished()) {
psWorker.setFinished(true);
psWorker.isFinished().notify();
}
System.out.println("I'm -> Worker. I left to work!");
}
}
public static class Boss implements Runnable {
private final ProcessStep psBoss;
private final ProcessStep psWorker;
private boolean running;
public Boss(ExecutorService executorService, ProcessStep psBoss, ProcessStep psWorker) {
this.psBoss = psBoss;
this.psWorker = psWorker;
executorService.submit(() -> {
System.out.println("Boss. I have Runnable for turn of me when is needed");
synchronized (this.psWorker.isFinished()) {
try {
psWorker.isFinished().wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
this.running = false;
});
executorService.submit(this);
}
@Override
public void run() {
System.out.println("I'm -> Boss. I'm delayed 4 Secs");
try {
Thread.sleep(4000);
} catch (Exception e) { }
System.out.println("I'm -> Boss. Let's go to check the work!");
synchronized (this.psBoss.isRunning()) {
psBoss.setRunning(true);
psBoss.isRunning().notifyAll();
}
running = true;
while (running) {
System.out.println("I'm Checking ...");
try {
Thread.sleep(1000);
} catch (Exception e) { }
}
synchronized (this.psBoss.isRunning()) {
psBoss.setRunning(false);
psBoss.isRunning().notify();
}
synchronized (this.psBoss.isFinished()) {
psBoss.setFinished(true);
psBoss.isFinished().notify();
}
System.out.println("I'm -> Boss The work end!");
}
}
public static class ProcessStep {
private final ReadWriteLock rwLock;
private Boolean running;
private Boolean finished;
public ProcessStep() {
this.rwLock = new ReentrantReadWriteLock();
running = false;
finished = false;
}
public Boolean isRunning() {
Lock readLock = rwLock.readLock();
readLock.lock();
try {
return running;
} finally {
readLock.unlock();
}
}
public void setRunning(Boolean running) {
Lock writeLock = rwLock.writeLock();
writeLock.lock();
try {
this.running = running;
} finally {
writeLock.unlock();
}
}
public Boolean isFinished() {
Lock readLock = rwLock.readLock();
readLock.lock();
try {
return finished;
} finally {
readLock.unlock();
}
}
public void setFinished(Boolean finished) {
Lock writeLock = rwLock.writeLock();
writeLock.lock();
try {
this.finished = finished;
} finally {
writeLock.unlock();
}
}
}
}
The output was
I'm -> Worker. I wait until Boss can see me!
Boss. I have Runnable for turn of me when is needed
I'm -> Boss. I'm delayed 4 Secs
I'm -> Boss. Let's go to check the work!
The Worker remain waiting!
Is it possible to use synchronized OVER the property?
Another version with same result was:
public static class Worker implements Runnable {
private final ProcessStep psWorker;
private final ProcessStep psBoss;
public Worker(ExecutorService executorService, ProcessStep psWorker, ProcessStep psBoss) {
this.psWorker = psWorker;
this.psBoss = psBoss;
executorService.submit(this);
}
@Override
public void run() {
System.out.println("I'm -> Worker. I wait until Boss can see me!");
synchronized (psBoss) {
try {
psBoss.isRunning().wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("I'm -> Worker. Boss is seeing to me!");
int counter = 0;
while (counter < 6) {
synchronized (psWorker) {
psWorker.setRunning(true);
psWorker.isRunning().notify();
}
System.out.println("I'm Working ...");
try {
Thread.sleep(1000);
} catch (Exception e) { }
counter++;
}
synchronized (psWorker) {
psWorker.setRunning(false);
psWorker.isRunning().notify();
}
synchronized (psWorker) {
psWorker.setFinished(true);
psWorker.isFinished().notify();
}
System.out.println("I'm -> Worker. I left to work!");
}
}
public static class Boss implements Runnable {
private final ProcessStep psBoss;
private final ProcessStep psWorker;
private boolean running;
public Boss(ExecutorService executorService, ProcessStep psBoss, ProcessStep psWorker) {
this.psBoss = psBoss;
this.psWorker = psWorker;
executorService.submit(() -> {
System.out.println("Boss. I have Runnable for turn of me when is needed");
synchronized (psWorker) {
try {
psWorker.isFinished().wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
this.running = false;
});
executorService.submit(this);
}
@Override
public void run() {
System.out.println("I'm -> Boss. I'm delayed 4 Secs");
try {
Thread.sleep(4000);
} catch (Exception e) { }
System.out.println("I'm -> Boss. Let's go to check the work!");
synchronized (psBoss) {
psBoss.setRunning(true);
psBoss.isRunning().notifyAll();
}
running = true;
while (running) {
System.out.println("I'm Checking ...");
try {
Thread.sleep(1000);
} catch (Exception e) { }
}
synchronized (psBoss) {
psBoss.setRunning(false);
psBoss.isRunning().notify();
}
synchronized (psBoss) {
psBoss.setFinished(true);
psBoss.isFinished().notify();
}
System.out.println("I'm -> Boss The work end!");
}
}
回答1:
I think , I got it!
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
public class SyncProt1 {
public static void main(String... args) {
List<Future<?>> futureList = new ArrayList<>();
ExecutorService executorService = Executors.newCachedThreadPool();
ProcessStep psWorker = new ProcessStep();
ProcessStep psBoss = new ProcessStep();
Worker worker = new Worker(futureList, executorService, psWorker, psBoss);
Boss boss = new Boss(futureList, executorService, psBoss, psWorker);
}
public static class Worker implements Runnable {
private final ProcessStep psWorker;
private final ProcessStep psBoss;
public Worker(List<Future<?>> futureList, ExecutorService executorService, ProcessStep psWorker, ProcessStep psBoss) {
this.psWorker = psWorker;
this.psBoss = psBoss;
futureList.add(executorService.submit(this));
}
@Override
public void run() {
System.out.println("I'm -> Worker. I wait until Boss can see me!");
synchronized (this.psBoss.getRunning()) {
try {
this.psBoss.getRunning().wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("I'm -> Worker. Boss is seeing to me!");
int counter = 0;
while (counter < 6) {
synchronized (this.psWorker.getRunning()) {
this.psWorker.getRunning().setStep(Boolean.TRUE);
psWorker.getRunning().notify();
}
System.out.println("I'm Working ...");
try {
Thread.sleep(1000);
} catch (Exception e) {
}
counter++;
}
synchronized (this.psWorker.getRunning()) {
this.psWorker.getRunning().setStep(Boolean.FALSE);
this.psWorker.getRunning().notify();
}
synchronized (this.psWorker.getFinished()) {
this.psWorker.getFinished().setStep(Boolean.TRUE);
this.psWorker.getFinished().notify();
}
System.out.println("I'm -> Worker. I left to work!");
}
}
public static class Boss implements Runnable {
private final ProcessStep psBoss;
private final ProcessStep psWorker;
private boolean running;
public Boss(List<Future<?>> futureList, ExecutorService executorService, ProcessStep psBoss, ProcessStep psWorker) {
this.psBoss = psBoss;
this.psWorker = psWorker;
futureList.add(executorService.submit(() -> {
System.out.println("Boss. I have Runnable for turn of me when is needed");
synchronized (this.psWorker.getFinished()) {
try {
this.psWorker.getFinished().wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("Boss. The worker Finished!");
this.running = false;
}));
futureList.add(executorService.submit(this));
}
@Override
public void run() {
System.out.println("I'm -> Boss. I'm delayed 4 Secs. " + new Date());
try {
Thread.sleep(4000);
} catch (Exception e) {
}
System.out.println("I'm -> Boss. Let's go to check the work at " + new Date());
synchronized (this.psBoss.getRunning()) {
this.psBoss.getRunning().setStep(Boolean.TRUE);
this.psBoss.getRunning().notify();
}
running = true;
while (running) {
System.out.println("I'm Checking ...");
try {
Thread.sleep(1000);
} catch (Exception e) {
}
}
synchronized (this.psBoss.getRunning()) {
this.psBoss.getRunning().setStep(Boolean.FALSE);
this.psBoss.getRunning().notify();
}
synchronized (this.psBoss.getFinished()) {
this.psBoss.getFinished().setStep(Boolean.TRUE);
this.psBoss.getFinished().notify();
}
System.out.println("I'm -> Boss The work end!");
}
}
public static class ProcessStep {
private final Step created = new Step();
private final Step running = new Step();
private final Step finished = new Step();
public Step getCreated() {
return created;
}
public Step getRunning() {
return running;
}
public Step getFinished() {
return finished;
}
}
public static class Step {
private final ReadWriteLock rwLock;
private Boolean step;
public Step() {
this.rwLock = new ReentrantReadWriteLock();
step = false;
}
public Boolean getStep() {
Lock readLock = rwLock.readLock();
readLock.lock();
try {
return step;
} finally {
readLock.unlock();
}
}
public void setStep(Boolean step) {
Lock writeLock = rwLock.writeLock();
writeLock.lock();
try {
this.step = step;
} finally {
writeLock.unlock();
}
}
}
}
The output
I'm -> Worker. I wait until Boss can see me!
Boss. I have Runnable for turn of me when is needed
I'm -> Boss. I'm delayed 4 Secs. Mon Aug 19 20:30:44 COT 2019
I'm -> Boss. Let's go to check the work at Mon Aug 19 20:30:48 COT 2019
I'm Checking ...
I'm -> Worker. Boss is seeing to me!
I'm Working ...
I'm Checking ...
I'm Working ...
I'm Checking ...
I'm Working ...
I'm Working ...
I'm Checking ...
I'm Checking ...
I'm Working ...
I'm Checking ...
I'm Working ...
I'm Checking ...
I'm -> Worker. I left to work!
Boss. The worker Finished!
I'm -> Boss The work end!
EDIT Removing Lock, ReadWriteLock and ReentrantReadWriteLock. Doing synchronized and Editing getStep and setStep methods.
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
public class SyncProt4 {
public static void main(String... args) {
List<Future<?>> futureList = new ArrayList<>();
ExecutorService executorService = Executors.newCachedThreadPool();
ProcessStep psWorker = new ProcessStep();
ProcessStep psBoss = new ProcessStep();
Worker worker = new Worker(futureList, executorService, psWorker, psBoss);
Boss boss = new Boss(futureList, executorService, psBoss, psWorker);
}
public static class Worker implements Runnable {
private final ProcessStep psWorker;
private final ProcessStep psBoss;
public Worker(List<Future<?>> futureList, ExecutorService executorService, ProcessStep psWorker, ProcessStep psBoss) {
this.psWorker = psWorker;
this.psBoss = psBoss;
futureList.add(executorService.submit(this));
}
@Override
public void run() {
System.out.println("I'm Worker -> I wait until Boss can see me!");
while (!this.psBoss.getRunning().getStep());
System.out.println("I'm Worker -> Boss is seeing to me!");
int counter = 0;
while (counter < 6) {
this.psWorker.getRunning().setStep(Boolean.TRUE);
System.out.println("I'm Worker -> I'm Working ...");
try {
Thread.sleep(1000);
} catch (Exception e) {
}
counter++;
}
this.psWorker.getRunning().setStep(Boolean.FALSE);
this.psWorker.getFinished().setStep(Boolean.TRUE);
System.out.println("I'm Worker -> I left to work!");
}
}
public static class Boss implements Runnable {
private final ProcessStep psBoss;
private final ProcessStep psWorker;
private boolean running;
public Boss(List<Future<?>> futureList, ExecutorService executorService, ProcessStep psBoss, ProcessStep psWorker) {
this.psBoss = psBoss;
this.psWorker = psWorker;
futureList.add(executorService.submit(() -> {
System.out.println("I'm Boss -> I have Runnable for turn of me when is needed");
while (!this.psWorker.getFinished().getStep());
System.out.println("I'm Boss -> The Worker Finished!");
this.running = false;
}));
futureList.add(executorService.submit(this));
}
@Override
public void run() {
System.out.println("I'm Boss -> I'm delayed 4 Secs. " + new Date());
try {
Thread.sleep(4000);
} catch (Exception e) {
}
System.out.println("I'm Boss -> Let's go to check the work at " + new Date());
this.psBoss.getRunning().setStep(Boolean.TRUE);
running = true;
while (running) {
System.out.println("I'm Boss -> I'm Checking ...");
try {
Thread.sleep(1000);
} catch (Exception e) {
}
}
this.psBoss.getRunning().setStep(Boolean.FALSE);
this.psBoss.getFinished().setStep(Boolean.TRUE);
System.out.println("I'm Boss -> The work ends!");
}
}
public static class ProcessStep {
private final Step created = new Step();
private final Step running = new Step();
private final Step finished = new Step();
public Step getCreated() {
return created;
}
public Step getRunning() {
return running;
}
public Step getFinished() {
return finished;
}
}
public static class Step {
private Boolean step;
public Step() {
step = false;
}
public synchronized Boolean getStep() {
try {
wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
return step;
}
public synchronized void setStep(Boolean step) {
this.step = step;
notifyAll();
}
}
}
The new output
I'm Worker -> I wait until Boss can see me!
I'm Boss -> I have Runnable for turn of me when is needed
I'm Boss -> I'm delayed 4 Secs. Tue Aug 20 21:27:26 COT 2019
I'm Boss -> Let's go to check the work at Tue Aug 20 21:27:30 COT 2019
I'm Boss -> I'm Checking ...
I'm Worker -> Boss is seeing to me!
I'm Worker -> I'm Working ...
I'm Boss -> I'm Checking ...
I'm Worker -> I'm Working ...
I'm Boss -> I'm Checking ...
I'm Worker -> I'm Working ...
I'm Boss -> I'm Checking ...
I'm Worker -> I'm Working ...
I'm Boss -> I'm Checking ...
I'm Worker -> I'm Working ...
I'm Boss -> I'm Checking ...
I'm Worker -> I'm Working ...
I'm Worker -> I left to work!
I'm Boss -> The Worker Finished!
I'm Boss -> I'm Checking ...
I'm Boss -> The work ends!
来源：https://stackoverflow.com/questions/57541384/synchronized-notify-wait-over-property-boolean-object-java-illegalmonitorstate