org.apache.ignite.cache.store

Class CacheLoadOnlyStoreAdapter<K,V,I>

java.lang.Object

org.apache.ignite.cache.store.CacheLoadOnlyStoreAdapter<K,V,I>

Type Parameters:

K - Key type.

V - Value type.

I - Input type.

All Implemented Interfaces:

javax.cache.integration.CacheLoader<K,V>, javax.cache.integration.CacheWriter<K,V>, CacheStore<K,V>

public abstract class CacheLoadOnlyStoreAdapter<K,V,I>
extends Object
implements CacheStore<K,V>

This adapter designed to support stores with bulk loading from stream-like source.

This class processes input data in the following way:

• Iterator of input record obtained from user-defined inputIterator(Object...).
• Iterator continuously queried for input records and they are grouped into batches of batchSize.
• Batch is placed into processing queue and puled by one of threadsCnt working threads.
• Each record in batch is passed to user-defined parse(Object, Object...) method and result is stored into cache.

Two methods should be implemented by inheritants:

• inputIterator(Object...). It should open underlying data source and iterate all record available in it. Individual records could be in very raw form, like text lines for CSV files.
• parse(Object, Object...). This method should process input records and transform them into key-value pairs for cache.

Field Summary

Fields

Modifier and Type	Field and Description
static int	DFLT_BATCH_QUEUE_SIZE Default batch queue size (max batches count to limit memory usage).
static int	DFLT_BATCH_SIZE Default batch size (number of records read with inputIterator(Object...)
static int	DFLT_THREADS_COUNT Default number of working threads (equal to the number of available processors).

Constructor Summary

Constructors

Constructor and Description
CacheLoadOnlyStoreAdapter()

Method Summary

Modifier and Type	Method and Description
void	delete(Object key)
void	deleteAll(Collection<?> keys)
int	getBatchQueueSize() Returns batch queue size.
int	getBatchSize() Returns batch size.
int	getThreadsCount() Returns number of worker threads.
protected abstract Iterator<I>	inputIterator(Object... args) Returns iterator of input records.
V	load(K key)
Map<K,V>	loadAll(Iterable<? extends K> keys)
void	loadCache(IgniteBiInClosure<K,V> c, Object... args) Loads all values from underlying persistent storage.
protected abstract IgniteBiTuple<K,V>	parse(I rec, Object... args) This method should transform raw data records into valid key-value pairs to be stored into cache.
void	sessionEnd(boolean commit) Tells store to commit or rollback a transaction depending on the value of the 'commit' parameter.
void	setBatchQueueSize(int batchQueueSize) Sets batch queue size.
void	setBatchSize(int batchSize) Sets batch size.
void	setThreadsCount(int threadsCnt) Sets number of worker threads.
void	write(javax.cache.Cache.Entry<? extends K,? extends V> entry)
void	writeAll(Collection<javax.cache.Cache.Entry<? extends K,? extends V>> entries)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DFLT_BATCH_SIZE

public static final int DFLT_BATCH_SIZE

Default batch size (number of records read with inputIterator(Object...) and then submitted to internal pool at a time).

See Also:

Constant Field Values

DFLT_BATCH_QUEUE_SIZE

public static final int DFLT_BATCH_QUEUE_SIZE

Default batch queue size (max batches count to limit memory usage).

See Also:

Constant Field Values

DFLT_THREADS_COUNT

public static final int DFLT_THREADS_COUNT

Default number of working threads (equal to the number of available processors).

Constructor Detail

CacheLoadOnlyStoreAdapter

public CacheLoadOnlyStoreAdapter()

Method Detail

inputIterator

protected abstract Iterator<I> inputIterator(@Nullable
                                             Object... args)
                                      throws javax.cache.integration.CacheLoaderException

Returns iterator of input records.

Note that returned iterator doesn't have to be thread-safe. Thus it could operate on raw streams, DB connections, etc. without additional synchronization.

Parameters:

args - Arguments passes into IgniteCache.loadCache(IgniteBiPredicate, Object...) method.

Returns:

Iterator over input records.

Throws:

javax.cache.integration.CacheLoaderException - If iterator can't be created with the given arguments.

parse

@Nullable
protected abstract IgniteBiTuple<K,V> parse(I rec,
                                                      @Nullable
                                                      Object... args)

This method should transform raw data records into valid key-value pairs to be stored into cache.

If null is returned then this record will be just skipped.

Parameters:

rec - A raw data record.

args - Arguments passed into IgniteCache.loadCache(IgniteBiPredicate, Object...) method.

Returns:

Cache entry to be saved in cache or null if no entry could be produced from this record.

loadCache

public void loadCache(IgniteBiInClosure<K,V> c,
                      @Nullable
                      Object... args)

Loads all values from underlying persistent storage. Note that keys are not passed, so it is up to implementation to figure out what to load. This method is called whenever IgniteCache.loadCache(IgniteBiPredicate, Object...) method is invoked which is usually to preload the cache from persistent storage.

This method is optional, and cache implementation does not depend on this method to do anything. Default implementation of this method in CacheStoreAdapter does nothing.

For every loaded value method IgniteBiInClosure.apply(Object, Object) should be called on the passed in closure. The closure will then make sure that the loaded value is stored in cache.

Specified by:

loadCache in interface CacheStore<K,V>

Parameters:

c - Closure for loaded values.

args - Arguments passes into IgniteCache.loadCache(IgniteBiPredicate, Object...) method.

getBatchSize

public int getBatchSize()

Returns batch size.

Returns:

Batch size.

setBatchSize

public void setBatchSize(int batchSize)

Sets batch size.

Parameters:

batchSize - Batch size.

getBatchQueueSize

public int getBatchQueueSize()

Returns batch queue size.

Returns:

Batch queue size.

setBatchQueueSize

public void setBatchQueueSize(int batchQueueSize)

Sets batch queue size.

Parameters:

batchQueueSize - Batch queue size.

getThreadsCount

public int getThreadsCount()

Returns number of worker threads.

Returns:

Number of worker threads.

setThreadsCount

public void setThreadsCount(int threadsCnt)

Sets number of worker threads.

Parameters:

threadsCnt - Number of worker threads.

load

public V load(K key)

Specified by:

load in interface javax.cache.integration.CacheLoader<K,V>

loadAll

public Map<K,V> loadAll(Iterable<? extends K> keys)

Specified by:

loadAll in interface javax.cache.integration.CacheLoader<K,V>

write

public void write(javax.cache.Cache.Entry<? extends K,? extends V> entry)

Specified by:

write in interface javax.cache.integration.CacheWriter<K,V>

writeAll

public void writeAll(Collection<javax.cache.Cache.Entry<? extends K,? extends V>> entries)

Specified by:

writeAll in interface javax.cache.integration.CacheWriter<K,V>

delete

public void delete(Object key)

Specified by:

delete in interface javax.cache.integration.CacheWriter<K,V>

deleteAll

public void deleteAll(Collection<?> keys)

Specified by:

deleteAll in interface javax.cache.integration.CacheWriter<K,V>

sessionEnd

public void sessionEnd(boolean commit)

Tells store to commit or rollback a transaction depending on the value of the 'commit' parameter.

Specified by:

sessionEnd in interface CacheStore<K,V>

Parameters:

commit - True if transaction should commit, false for rollback.