使用session.save保存对象时，Hibernate不会刷新会话？

Question

First of all take a look at below code, I have three main model to manage StoreHouse and StoreHouseInvetory 's and have other model named StoreHouseInventoryLock to temporary lock/unlock some amount of StoreHouseInvetory 's when other processes wants to use these models:

public class StoreHouse {
    private String  name;
    private Double  currentAmount;
}

public class StoreHouseInventory {
    private StoreHouse  storeHouse;
    private Good        good;
    private Double      amount;
}

public class StoreHouseInventoryLock {
    private StoreHouseInventory     inventory;
    private Double                  amount;
}

@Service
public class PermitService implements IPermitService {

    @Autowired
    private IStoreHouseInventoryLockService storeHouseInventoryLockService;

    @Autowired
    private IStoreHouseService storeHouseService;

    @Override
    @Transactional
    public void addDetailToPermitFromStoreHouseInventory(long permitId, long storeHouseId, long inventoryId, double amount) {

        // do some business logic here

        /* save is simple method
         * and uses Session.save(object)
        */
        storeHouseInventoryLockService.add(inventoryId, +amount);

        // do some business logic here
        storeHouseService.syncCurrentInventory(storeHouseId);   
    }
}

@Service
public class StoreHouseService implements IStoreHouseService {

    @Autowired
    private IStoreHouseInventoryService storeHouseInventoryService;

    @Autowired
    private IStoreHouseInventoryLockService storeHouseInventoryLockService;

    @Transactional
    public void syncCurrentInventory(storeHouseId) {
        /* is a simeple method that use query like below
         * select sum(e.amount)
         *   from StoreHouseInventory
         *  where e.storeHouse.id = :storeHouseId
         */
        Double sumOfInventory = storeHouseInventoryService.sumOfInventory(storeHouseId);
        /* is a simeple method that use query like below
         * select sum(e.amount)
         *   from StoreHouseInventoryLock
         *  where e.storeHouseInventory.storeHouse.id = :storeHouseId
         */
        Double sumOfLock = storeHouseInventoryService.sumOfLock(storeHouseId);

        // load method is a simple method to load object by it's id
        // and used from Session.get(String entityName, Serializable id)
        StoreHouse storeHouse = this.load(storeHouseId);
        storeHouse.setCurrentAmount(sumOfInventory - sumOfLock);

        this.save(storeHouse);
    }
}

the problem is that when storeHouseInventoryService.sumOfLock is called in StoreHouseService.syncCurrentInventory , it does not be aware change of storeHouseInventoryLockService.add method in PermitService.addDetailToPermitFromStoreHouseInventory method, and calcuates sum of locks incorrectly.

I think this is because of session was not flushed when I call storeHouseInventoryLockService.add . If it's true, why hibernate does not flsuh session during this changes? If not, what should I do?

Answer 1

As IStoreHouseInventoryLockService.add is called from within a method which already has a transaction attached to it, then the same transaction is propagated to the add method, thus the flush does not happen until the outer addDetailToPermitFromStoreHouseInventory finishes.

A quick solution for you would be to mark the add method with a REQUIRES_NEW transaction propagation type:

@Transactional(propagation=Propagation.REQUIRES_NEW)
public void add(..){..}

Now after that method finishes, even though there is an outer transaction, all the persistence changes will be flushed to the database on exit.

Answer 2

如果当前正在执行的查询与未刷新的表语句不重叠，则可以安全地忽略刷新。