log.tracef("Perform write skew check for key %s but the key was not read. Skipping check!", key);
}
//version seen is null when the entry was not read. In this case, the write skew is not needed.
return true;
}
EntryVersion prevVersion;
InternalCacheEntry ice = container.get(key);
if (ice == null) {
if (log.isTraceEnabled()) {
log.tracef("No entry for key %s found in data container" , key);
}
prevVersion = ctx.getCacheTransaction().getLookedUpRemoteVersion(key);
if (prevVersion == null) {
if (log.isTraceEnabled()) {
log.tracef("No looked up remote version for key %s found in context" , key);
}
//in this case, the key does not exist. So, the only result possible is the version seen be the NonExistingVersion
return versionGenerator.nonExistingVersion().compareTo(versionSeen) == InequalVersionComparisonResult.EQUAL;
}
} else {
prevVersion = ice.getMetadata().version();
if (prevVersion == null)
throw new IllegalStateException("Entries cannot have null versions!");
}
if (log.isTraceEnabled()) {
log.tracef("Is going to compare versions %s and %s for key %s.", prevVersion, versionSeen, key);
}
//in this case, the transaction read some value and the data container has a value stored.
//version seen and previous version are not null. Simple version comparation.
InequalVersionComparisonResult result = prevVersion.compareTo(versionSeen);
if (log.isTraceEnabled()) {
log.tracef("Comparing versions %s and %s for key %s: %s", prevVersion, versionSeen, key, result);
}
return InequalVersionComparisonResult.AFTER != result;
}