org.hibernate.cache

Interface CacheConcurrencyStrategy

Known Implementing Classes:
NonstrictReadWriteCache, ReadOnlyCache, ReadWriteCache, TransactionalCache

public interface CacheConcurrencyStrategy

Implementors manage transactional access to cached data. Transactions pass in a timestamp indicating transaction start time. Two different implementation patterns are provided for.

In terms of entity caches, the expected call sequences are:

In terms of collection caches, all modification actions actually just invalidate the entry(s). The call sequence here is: lock(Object,Object) -> evict(Object) -> release(Object,SoftLock)

Note that, for an asynchronous cache, cache invalidation must be a two step process (lock->release, or lock-afterUpdate), since this is the only way to guarantee consistency with the database for a nontransactional cache implementation. For a synchronous cache, cache invalidation is a single step process (evict, or update). Hence, this interface defines a three step process, to cater for both models.

Note that query result caching does not go through a concurrency strategy; they are managed directly against the underlying cache regions.

Method Summary

boolean
afterInsert(Object key, Object value, Object version)
Called after an item has been inserted (after the transaction completes), instead of calling release().
boolean
afterUpdate(Object key, Object value, Object version, SoftLock lock)
Called after an item has been updated (after the transaction completes), instead of calling release().
void
clear()
Evict all items from the cache immediately.
void
destroy()
Clean up all resources.
void
evict(Object key)
Called after an item has become stale (before the transaction completes).
Object
get(Object key, long txTimestamp)
Attempt to retrieve an object from the cache.
Cache
getCache()
Get the wrapped cache implementation
String
getRegionName()
Get the cache region name
boolean
insert(Object key, Object value, Object currentVersion)
Called after an item has been inserted (before the transaction completes), instead of calling evict().
SoftLock
lock(Object key, Object version)
We are going to attempt to update/delete the keyed object.
boolean
put(Object key, Object value, long txTimestamp, Object version, Comparator versionComparator, boolean minimalPut)
Attempt to cache an object, after loading from the database.
void
release(Object key, SoftLock lock)
Called when we have finished the attempted update/delete (which may or may not have been successful), after transaction completion.
void
remove(Object key)
Evict an item from the cache immediately (without regard for transaction isolation).
void
setCache(Cache cache)
Set the underlying cache implementation.
boolean
update(Object key, Object value, Object currentVersion, Object previousVersion)
Called after an item has been updated (before the transaction completes), instead of calling evict().

Method Details

afterInsert

public boolean afterInsert(Object key,
                           Object value,
                           Object version)
            throws CacheException
Called after an item has been inserted (after the transaction completes), instead of calling release(). This method is used by "asynchronous" concurrency strategies.

afterUpdate

public boolean afterUpdate(Object key,
                           Object value,
                           Object version,
                           SoftLock lock)
            throws CacheException
Called after an item has been updated (after the transaction completes), instead of calling release(). This method is used by "asynchronous" concurrency strategies.

clear

public void clear()
            throws CacheException
Evict all items from the cache immediately.
Throws:
CacheException -

destroy

public void destroy()
Clean up all resources.

evict

public void evict(Object key)
            throws CacheException
Called after an item has become stale (before the transaction completes). This method is used by "synchronous" concurrency strategies.

get

public Object get(Object key,
                  long txTimestamp)
            throws CacheException
Attempt to retrieve an object from the cache. Mainly used in attempting to resolve entities/collections from the second level cache.
Parameters:
key -
txTimestamp - a timestamp prior to the transaction start time
Returns:
the cached object or null
Throws:
CacheException -

getCache

public Cache getCache()
Get the wrapped cache implementation

getRegionName

public String getRegionName()
Get the cache region name

insert

public boolean insert(Object key,
                      Object value,
                      Object currentVersion)
            throws CacheException
Called after an item has been inserted (before the transaction completes), instead of calling evict(). This method is used by "synchronous" concurrency strategies.

lock

public SoftLock lock(Object key,
                     Object version)
            throws CacheException
We are going to attempt to update/delete the keyed object. This method is used by "asynchronous" concurrency strategies.

The returned object must be passed back to release(), to release the lock. Concurrency strategies which do not support client-visible locks may silently return null.

Parameters:
key -
version -
Throws:
CacheException -

put

public boolean put(Object key,
                   Object value,
                   long txTimestamp,
                   Object version,
                   Comparator versionComparator,
                   boolean minimalPut)
            throws CacheException
Attempt to cache an object, after loading from the database.
Parameters:
key -
value -
txTimestamp - a timestamp prior to the transaction start time
version - the item version number
versionComparator - a comparator used to compare version numbers
minimalPut - indicates that the cache should avoid a put is the item is already cached
Returns:
true if the object was successfully cached
Throws:
CacheException -

release

public void release(Object key,
                    SoftLock lock)
            throws CacheException
Called when we have finished the attempted update/delete (which may or may not have been successful), after transaction completion. This method is used by "asynchronous" concurrency strategies.
Parameters:
key -
Throws:
CacheException -

remove

public void remove(Object key)
            throws CacheException
Evict an item from the cache immediately (without regard for transaction isolation).
Parameters:
key -
Throws:
CacheException -

setCache

public void setCache(Cache cache)
Set the underlying cache implementation.
Parameters:
cache -

update

public boolean update(Object key,
                      Object value,
                      Object currentVersion,
                      Object previousVersion)
            throws CacheException
Called after an item has been updated (before the transaction completes), instead of calling evict(). This method is used by "synchronous" concurrency strategies.