// need 'synchronized' to ensure atomic initialization of merged data
// because several threads that acquired read lock may simultaneously execute the method
private ValueContainerImpl<Value> getMergedData() {
ValueContainerImpl<Value> merged = myMerged;
if (merged != null) {
return merged;
}
synchronized (myInitializer.getLock()) {
merged = myMerged;
if (merged != null) {
return merged;
}
final ValueContainer<Value> fromDisk = myInitializer.compute();
final ValueContainerImpl<Value> newMerged;
if (fromDisk instanceof ValueContainerImpl) {
newMerged = ((ValueContainerImpl<Value>) fromDisk).copy();
} else {
newMerged = ((ChangeTrackingValueContainer<Value>) fromDisk).getMergedData().copy();
}
TIntHashSet invalidated = myInvalidated;
if (invalidated != null) {
invalidated.forEach(
new TIntProcedure() {
@Override
public boolean execute(int inputId) {
newMerged.removeAssociatedValue(inputId);
return true;
}
});
}
ValueContainerImpl<Value> added = myAdded;
if (added != null) {
added.forEach(
new ContainerAction<Value>() {
@Override
public boolean perform(final int id, final Value value) {
newMerged.removeAssociatedValue(
id); // enforcing "one-value-per-file for particular key" invariant
newMerged.addValue(id, value);
return true;
}
});
}
setNeedsCompacting(fromDisk.needsCompacting());
myMerged = newMerged;
return newMerged;
}
}
