* Use !isEmpty() instead of "size() > 0" or "size() != 0"
!isEmpty() expresses the intent more clearly and is therefore preferred.
Counting the number of elements can also be an expensive operation e.g. when using linked lists.
Co-Authored-By: Christoph Weitkamp <github@christophweitkamp.de>
Signed-off-by: Wouter Born <github@maindrain.net>
Fixes the SAT warning: First javadoc author should have "Initial contribution" contribution description.
Signed-off-by: Wouter Born <github@maindrain.net>
The singleton instance of "Diagnostician" is used without
synchronization.
The singleton "Diasnostician" instance is using the singleton
"EValidator.Registry" instance (without synchronization).
In very rare high load situations there has been CME detected.
My first "solution" has been to synchronize the access of
Diagnostician's instance method by using
```java
synchronized (Diagnostician.INSTANCE) {
...
```
But after realize that EMF is using internally other singletons I tried
to find any information about EMF and thread safety.
I found this one: https://javahacks.net/2016/07/13/emf-thread-safety/
EMF models are not thread-safe by default and writing multithreaded
applications is not that simple.
The more complex our application became, the more often we got
concurrent modification exceptions and had problems with filtering and
sorting operations.
So, I assume instead of adding synchronizations to our code that is
using EMF (IIRC this has been already done on the ESH hosted code base
long time ago) we should try to execute EMF code in a safe manner.
This implementation adds a "SafeEMF" OSGi service that should be used to
execute EMF code to ensure none code of EMF (or at least the ones that
calls has been migrated to the SafeEMF usage) is accessed by separate
threads at the same time.
Related to: https://github.com/openhab/openhab-core/issues/772
Signed-off-by: Markus Rathgeb <maggu2810@gmail.com>
