EJB Singleton - Lock READ method calling a Lock WRITE method of the same instance
Given a Singleton like this one:
@Singleton
public class waitingTimeManager {
private Map<Integer, Object> waitingTimes;
@PostConstruct
public void setup() {
waitingTimes = new HashMap<>();
}
@Lock(LockType.READ)
public boolean shouldWeWait(Integer id) {
if (waitingTimes.containsKey(id)) {
boolean wait = someLogic(waitingTimes.get(id));
if (!wait) {
// we don't need to wait for it anymore
stopWaiting(id);
}
return wait;
}
return false;
}
@Lock(LockType.WRITE)
public void stopWaiting(Integer id){
waitingTimes.remove(id);
}
}
The initial method shouldWeWait can be accessed at the same time by several threads. The other stopWaiting will need to get a write lock.
Will the call to stopWaiting inside shouldWeWait try to get a WRITE Lock? or simply execute it as it already got the READ Lock initially?
java concurrency singleton ejb
asked Nov 15 '18 at 10:06
Daniel RodríguezDaniel Rodríguez
1531316
add a comment |
Given a Singleton like this one:
@Singleton
public class waitingTimeManager {
private Map<Integer, Object> waitingTimes;
@PostConstruct
public void setup() {
waitingTimes = new HashMap<>();
}
@Lock(LockType.READ)
public boolean shouldWeWait(Integer id) {
if (waitingTimes.containsKey(id)) {
boolean wait = someLogic(waitingTimes.get(id));
if (!wait) {
// we don't need to wait for it anymore
stopWaiting(id);
}
return wait;
}
return false;
}
@Lock(LockType.WRITE)
public void stopWaiting(Integer id){
waitingTimes.remove(id);
}
}
The initial method shouldWeWait can be accessed at the same time by several threads. The other stopWaiting will need to get a write lock.
Will the call to stopWaiting inside shouldWeWait try to get a WRITE Lock? or simply execute it as it already got the READ Lock initially?
java concurrency singleton ejb
asked Nov 15 '18 at 10:06
Daniel RodríguezDaniel Rodríguez
1531316
2
AFAIK the@LockonstopWaitingis not recognized since you have to invoke it on the business object and not onthis.
– Meini
Nov 15 '18 at 10:16
add a comment |
Given a Singleton like this one:
@Singleton
public class waitingTimeManager {
private Map<Integer, Object> waitingTimes;
@PostConstruct
public void setup() {
waitingTimes = new HashMap<>();
}
@Lock(LockType.READ)
public boolean shouldWeWait(Integer id) {
if (waitingTimes.containsKey(id)) {
boolean wait = someLogic(waitingTimes.get(id));
if (!wait) {
// we don't need to wait for it anymore
stopWaiting(id);
}
return wait;
}
return false;
}
@Lock(LockType.WRITE)
public void stopWaiting(Integer id){
waitingTimes.remove(id);
}
}
The initial method shouldWeWait can be accessed at the same time by several threads. The other stopWaiting will need to get a write lock.
Will the call to stopWaiting inside shouldWeWait try to get a WRITE Lock? or simply execute it as it already got the READ Lock initially?
java concurrency singleton ejb
asked Nov 15 '18 at 10:06
Daniel RodríguezDaniel Rodríguez
1531316
Given a Singleton like this one:
@Singleton
public class waitingTimeManager {
private Map<Integer, Object> waitingTimes;
@PostConstruct
public void setup() {
waitingTimes = new HashMap<>();
}
@Lock(LockType.READ)
public boolean shouldWeWait(Integer id) {
if (waitingTimes.containsKey(id)) {
boolean wait = someLogic(waitingTimes.get(id));
if (!wait) {
// we don't need to wait for it anymore
stopWaiting(id);
}
return wait;
}
return false;
}
@Lock(LockType.WRITE)
public void stopWaiting(Integer id){
waitingTimes.remove(id);
}
}
The initial method shouldWeWait can be accessed at the same time by several threads. The other stopWaiting will need to get a write lock.
Will the call to stopWaiting inside shouldWeWait try to get a WRITE Lock? or simply execute it as it already got the READ Lock initially?
java concurrency singleton ejb
java concurrency singleton ejb
asked Nov 15 '18 at 10:06
Daniel RodríguezDaniel Rodríguez
1531316
asked Nov 15 '18 at 10:06
Daniel RodríguezDaniel Rodríguez
1531316
edited Nov 15 '18 at 10:20
Daniel Rodríguez
asked Nov 15 '18 at 10:06
Daniel RodríguezDaniel Rodríguez
1531316
asked Nov 15 '18 at 10:06
Daniel RodríguezDaniel Rodríguez
1531316
asked Nov 15 '18 at 10:06
Daniel RodríguezDaniel Rodríguez
1531316
1531316
2
AFAIK the@LockonstopWaitingis not recognized since you have to invoke it on the business object and not onthis.
– Meini
Nov 15 '18 at 10:16
add a comment |
2
AFAIK the@LockonstopWaitingis not recognized since you have to invoke it on the business object and not onthis.
– Meini
Nov 15 '18 at 10:16
2
2
AFAIK the
@Lock on stopWaiting is not recognized since you have to invoke it on the business object and not on this.– Meini
Nov 15 '18 at 10:16
AFAIK the
@Lock on stopWaiting is not recognized since you have to invoke it on the business object and not on this.– Meini
Nov 15 '18 at 10:16
add a comment |
1 Answer
1
active
oldest
votes
No, it won't try to get write lock.
Container job is done within interceptors, wrapping EJB method calls. For example, when stateless BeanA calls your singleton - it does so through proxy, which makes possible the guarantees given by container (retrieving lock, etc.).
But in this case, it's just a normal method call (stopWaiting), not wrapped by proxy, so no place for magic.
answered Nov 15 '18 at 10:20
user3714601user3714601
764720
add a comment |
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1 Answer
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active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
No, it won't try to get write lock.
Container job is done within interceptors, wrapping EJB method calls. For example, when stateless BeanA calls your singleton - it does so through proxy, which makes possible the guarantees given by container (retrieving lock, etc.).
But in this case, it's just a normal method call (stopWaiting), not wrapped by proxy, so no place for magic.
answered Nov 15 '18 at 10:20
user3714601user3714601
764720
add a comment |
No, it won't try to get write lock.
Container job is done within interceptors, wrapping EJB method calls. For example, when stateless BeanA calls your singleton - it does so through proxy, which makes possible the guarantees given by container (retrieving lock, etc.).
But in this case, it's just a normal method call (stopWaiting), not wrapped by proxy, so no place for magic.
answered Nov 15 '18 at 10:20
user3714601user3714601
764720
add a comment |
No, it won't try to get write lock.
Container job is done within interceptors, wrapping EJB method calls. For example, when stateless BeanA calls your singleton - it does so through proxy, which makes possible the guarantees given by container (retrieving lock, etc.).
But in this case, it's just a normal method call (stopWaiting), not wrapped by proxy, so no place for magic.
answered Nov 15 '18 at 10:20
user3714601user3714601
764720
No, it won't try to get write lock.
Container job is done within interceptors, wrapping EJB method calls. For example, when stateless BeanA calls your singleton - it does so through proxy, which makes possible the guarantees given by container (retrieving lock, etc.).
But in this case, it's just a normal method call (stopWaiting), not wrapped by proxy, so no place for magic.
answered Nov 15 '18 at 10:20
user3714601user3714601
764720
answered Nov 15 '18 at 10:20
user3714601user3714601
764720
answered Nov 15 '18 at 10:20
user3714601user3714601
764720
answered Nov 15 '18 at 10:20
user3714601user3714601
764720
764720
add a comment |
add a comment |
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2
AFAIK the
@LockonstopWaitingis not recognized since you have to invoke it on the business object and not onthis.– Meini
Nov 15 '18 at 10:16