org.shoal.ha.cache.api
Interface DataStore<K,V>

All Known Implementing Classes:

ReplicatedDataStore

public interface DataStore<K,V>

A DataStore allows (#{Serializable} / #{Storable}) objects to be placed in the cache. The cache itself is created and configured using a #{DataStoreFactory}.

Author:

Mahesh Kannan

Method Summary

void	close() Close this datastore.
java.util.Collection	find(DataStoreEntryEvaluator<K,V> evaluator) Finds / Retrieves values that satisfy a criteria as dictated by the evaluator.
V	get(K k) Returns the value to which the specified key is mapped in this cache.
java.lang.String	put(K k, V v) Creates or Replaces the object associated with key k.
void	remove(K k) Removes the mapping between the key and the object.
int	removeIdleEntries(long idleFor) Removes all entries that were not accessed for more than 'idlefor' millis
java.lang.String	touch(K k, long version, long timeStamp, long ttl) Updates the timestamp associated with this entry.
void	update(DataStoreEntryEvaluator<K,V> evaluator) Updates all existing values associated with a key using the evaluator.
java.lang.String	updateDelta(K k, V delta) Performs an incremental update of the value associated with this key.

Method Detail

put

java.lang.String put(K k,
                     V v)
                     throws DataStoreException

Creates or Replaces the object associated with key k.

Parameters:

k - The Key

v - The value. The value must be either serializable of the DataStoreEntryHelper that is associated with this cache must be able to transform this into a serializable.

Throws:

DataStoreException

get

V get(K k)
      throws DataStoreException

Returns the value to which the specified key is mapped in this cache.

Parameters:

k - The key

Returns:

The value if the association exists or null.

Throws:

DataStoreException

remove

void remove(K k)
            throws DataStoreException

Removes the mapping between the key and the object.

Parameters:

k - The key

Throws:

DataStoreException

touch

java.lang.String touch(K k,
                       long version,
                       long timeStamp,
                       long ttl)
                       throws DataStoreException

Updates the timestamp associated with this entry. see #{removeIdleEntries}

Parameters:

k - The key

Throws:

DataStoreException

updateDelta

java.lang.String updateDelta(K k,
                             V delta)
                             throws DataStoreException

Performs an incremental update of the value associated with this key. The DataStore's DataStoreEntryHelper.updateState() method will be called with the key, the DataStoreEnrty and the delta. If no value is associated with K, then a hollow DataStoreEntry will be passed to DataStoreEntryHelper.updateState().

Parameters:

k - The key

delta - The object whose eval() method will be called.

Throws:

DataStoreException

See Also:

#{DataStoreEntryEvaluator.eval}

find

java.util.Collection find(DataStoreEntryEvaluator<K,V> evaluator)

Finds / Retrieves values that satisfy a criteria as dictated by the evaluator. The evaluator's eval() method will be called with both the key and the existing value.

Parameters:

evaluator - The StoreEntryEvaluator whose eval() method will be called.

See Also:

#{DataStoreEntryEvaluator.eval}

update

void update(DataStoreEntryEvaluator<K,V> evaluator)

Updates all existing values associated with a key using the evaluator. The evaluator's eval() method will be called with both the key and the existing value.

Parameters:

evaluator - The StoreEntryEvaluator whose eval() method will be called.

See Also:

#{DataStoreEntryEvaluator.eval}

removeIdleEntries

int removeIdleEntries(long idleFor)

Removes all entries that were not accessed for more than 'idlefor' millis

Parameters:

idleFor - Time in milli seconds

close

void close()

Close this datastore. This causes all data to be removed(?)