Why multi-threading is blocking with configuing withShouldSkipBlockingWait = True #103
Description
main
ExecutorService executorService = Executors.newFixedThreadPool(2);
executorService.submit(new CakeEater(lockClient, "User 1", 20000));
executorService.submit(new CakeEater(lockClient, "User 2",10000));CakeEater
static class CakeEater implements Runnable {
private final AmazonDynamoDBLockClient lockClient;
private final String userName;
private final long eatingSpeed;
public CakeEater(AmazonDynamoDBLockClient lockClient, String userName, long eatingSpeed) {
this.lockClient = lockClient;
this.userName = userName;
this.eatingSpeed = eatingSpeed;
}
@Override
public void run(){
if (cakePieces > 0) {
final Optional<LockItem> lockItem;
try {
System.out.println(userName + ": trying to get lock");
lockItem =
lockClient.tryAcquireLock(AcquireLockOptions.builder(PARTITION_KEY).withShouldSkipBlockingWait(true).build());
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
if (lockItem.get() != null ) {
System.out.println(userName + " got key: " + lockItem);
try {
Thread.sleep(eatingSpeed); // Simulate eating time
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
cakePieces -= 1;
System.out.println(userName + " ate a piece of cake. Remaining pieces: " + cakePieces);
lockClient.releaseLock(lockItem.get());
} else
{
System.out.println(userName + " is waiting a lock");
try {
throw new Exception("lock is held by other");
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
}
}
}Sep 09, 2024 12:26:26 AM io.harry.utils.DynamoDbClientTest$CakeEater run
INFO: User 2: trying to get lock
Sep 09, 2024 12:26:26 AM io.harry.utils.DynamoDbClientTest$CakeEater run
INFO: User 1: trying to get lock
Sep 09, 2024 12:26:27 AM io.harry.utils.DynamoDbClientTest$CakeEater run
INFO: User 1 got key: Optional[LockItem{Partition Key=key, Sort Key=Optional.empty, Owner Name=HG976G70QVf8210aae-73ff-45c8-9a19-4c541e5925ff, Lookup Time=917462271, Lease Duration=50000, Record Version Number=0269d63d-8844-40e5-8cdc-80289cf92326, Delete On Close=true, Data=, Is Released=false}]
Sep 09, 2024 12:26:47 AM io.harry.utils.DynamoDbClientTest$CakeEater run
INFO: User 1 ate a piece of cake. Remaining pieces: 9
I was expecting use2 raise exception after user 1 got the lock