ChangeSet () { if (currentBlock == null) { synchronized (ChangeList.this) { if (myCurrentChangeSet != null) { currentBlock = new ChangeSetHolder(-1, myCurrentChangeSet); } else { currentBlock = myStorage.readPrevious(-1, recursionGuard); } } } else { synchronized (ChangeList.this) { currentBlock = myStorage.readPrevious(currentBlock.id(), recursionGuard); } } if (currentBlock == null) return null; return currentBlock.changeSet(); }