public class JdbcStringBasedStore extends Object implements AdvancedLoadWriteStore
AdvancedCacheLoader implementation that stores the entries in a database. In contrast to the
JdbcBinaryStore, this cache store will store each entry within a row
in the table (rather than grouping multiple entries into an row). This assures a finer grained granularity for all
operation, and better performance. In order to be able to store non-string keys, it relies on an Key2StringMapper.
Note that only the keys are stored as strings, the values are still saved as binary data. Using a character
data type for the value column will result in unmarshalling errors.
The actual storage table is defined through configuration JdbcStringBasedStoreConfiguration. The table can
be
created/dropped on-the-fly, at deployment time. For more details consult javadoc for JdbcStringBasedStoreConfiguration.
It is recommended to use JdbcStringBasedStore} over
JdbcBinaryStore} whenever it is possible, as is has a better performance.
One scenario in which this is not possible to use it though, is when you can't write an Key2StringMapper} to map the
keys to to string objects (e.g. when you don't have control over the types of the keys, for whatever reason).
Preload.In order to support preload functionality the store needs to read the string keys from the database and transform them
into the corresponding key objects. Key2StringMapper only supports
key to string transformation(one way); in order to be able to use preload one needs to specify an
TwoWayKey2StringMapper, which extends Key2StringMapper and
allows bidirectional transformation.
Rehashing. When a node leaves/joins, Infinispan moves around persistent state as part of rehashing process.
For this it needs access to the underlaying key objects, so if distribution is used, the mapper needs to be an
TwoWayKey2StringMapper otherwise the cache won't start (same constraint as with preloading).Key2StringMapper,
DefaultTwoWayKey2StringMapperAdvancedCacheLoader.CacheLoaderTask<K,V>, AdvancedCacheLoader.TaskContextAdvancedCacheWriter.PurgeListener<K>| Constructor and Description |
|---|
JdbcStringBasedStore() |
| Modifier and Type | Method and Description |
|---|---|
void |
clear()
Removes all the data from the storage.
|
boolean |
contains(Object key)
Returns true if the storage contains an entry associated with the given key.
|
boolean |
delete(Object key) |
ConnectionFactory |
getConnectionFactory() |
TableManipulation |
getTableManipulation() |
void |
init(InitializationContext ctx)
Used to initialize a cache loader.
|
void |
initializeConnectionFactory(ConnectionFactory connectionFactory)
Keeps a reference to the connection factory for further use.
|
boolean |
isDistributed() |
MarshalledEntry |
load(Object key)
Fetches an entry from the storage.
|
void |
process(KeyFilter filter,
AdvancedCacheLoader.CacheLoaderTask task,
Executor executor,
boolean fetchValue,
boolean fetchMetadata)
Iterates in parallel over the entries in the storage using the threads from the executor pool.
|
void |
purge(Executor executor,
AdvancedCacheWriter.PurgeListener task)
Using the thread in the pool, removed all the expired data from the persistence storage.
|
int |
size()
Returns the number of elements in the store.
|
void |
start()
Invoked on component start
|
void |
stop()
Invoked on component stop
|
boolean |
supportsKey(Class<?> keyType) |
void |
write(MarshalledEntry entry)
Persists the entry to the storage.
|
public void init(InitializationContext ctx)
CacheLoaderPersistenceManager
when setting up cache loaders.init in interface CacheLoaderinit in interface CacheWriterpublic void start()
Lifecyclepublic void stop()
Lifecyclepublic void write(MarshalledEntry entry)
CacheWriterwrite in interface CacheWriterMarshalledEntrypublic MarshalledEntry load(Object key)
CacheLoaderMarshalledEntry needs to be created here, InitializationContext.getMarshalledEntryFactory() and InitializationContext.getByteBufferFactory() should be used.load in interface CacheLoaderpublic boolean delete(Object key)
delete in interface CacheWriterpublic void clear()
throws PersistenceException
AdvancedCacheWriterclear in interface AdvancedCacheWriterPersistenceException - in case of an error, e.g. communicating with the external storagepublic void purge(Executor executor, AdvancedCacheWriter.PurgeListener task)
AdvancedCacheWriterpurge in interface AdvancedCacheWriterpublic boolean contains(Object key)
CacheLoadercontains in interface CacheLoaderpublic void process(KeyFilter filter, AdvancedCacheLoader.CacheLoaderTask task, Executor executor, boolean fetchValue, boolean fetchMetadata)
AdvancedCacheLoaderCacheLoaderTask#processEntry(MarshalledEntry, TaskContext) is
invoked. Before passing an entry to the callback task, the entry should be validated against the filter.
Implementors should build an AdvancedCacheLoader.TaskContext instance (implementation) that is fed to the AdvancedCacheLoader.CacheLoaderTask on every invocation. The AdvancedCacheLoader.CacheLoaderTask might invoke AdvancedCacheLoader.TaskContext.stop() at any time, so implementors of this method
should verify TaskContext's state for early termination of iteration. The method should only return once the
iteration is complete or as soon as possible in the case TaskContext.stop() is invoked.process in interface AdvancedCacheLoaderfilter - to validate which entries should be feed into the task. Might be null.task - callback to be invoked in parallel for each stored entry that passes the filter checkexecutor - an external thread pool to be used for parallel iterationfetchValue - whether or not to fetch the value from the persistent store. E.g. if the iteration is
intended only over the key set, no point fetching the values from the persistent store as
wellfetchMetadata - whether or not to fetch the metadata from the persistent store. E.g. if the iteration is
intended only ove the key set, then no pint fetching the metadata from the persistent store
as wellpublic int size()
AdvancedCacheLoadersize in interface AdvancedCacheLoaderpublic boolean supportsKey(Class<?> keyType)
public void initializeConnectionFactory(ConnectionFactory connectionFactory) throws PersistenceException
TableManipulation that needs connections. This method should be called when you don't
want the store to manage the connection factory, perhaps because it is using an shared connection factory: see
JdbcMixedStore for such an example of this.PersistenceExceptionpublic ConnectionFactory getConnectionFactory()
public TableManipulation getTableManipulation()
public boolean isDistributed()
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