@Override
public void copyForUpdate(DataContainer container, boolean writeSkewCheck) {
if (isChanged()) return; // already copied
// mark entry as changed.
setChanged();
if (writeSkewCheck) {
// check for write skew.
InternalCacheEntry ice = container.get(key);
Object actualValue = ice == null ? null : ice.getValue();
// Note that this identity-check is intentional. We don't *want* to call actualValue.equals()
// since that defeats the purpose.
// the implicit "versioning" we have in R_R creates a new wrapper "value" instance for every
// update.
if (actualValue != null && actualValue != value) {
String errormsg =
new StringBuilder()
.append("Detected write skew on key [")
.append(getKey())
.append("]. Another process has changed the entry since we last read it!")
.toString();
if (log.isWarnEnabled()) log.warn(errormsg + ". Unable to copy entry for update.");
throw new CacheException(errormsg);
}
}
// make a backup copy
oldValue = value;
}
