com.hazelcast.mapreduce.impl

Class MultiMapKeyValueSource<K,V>

java.lang.Object

com.hazelcast.mapreduce.KeyValueSource<K,V>

com.hazelcast.mapreduce.impl.MultiMapKeyValueSource<K,V>

Type Parameters:

K - type of the key of the MultiMap

V - type of the value of the MultiMap

All Implemented Interfaces:

PartitionIdAware, DataSerializable, IdentifiedDataSerializable, Closeable, AutoCloseable

public class MultiMapKeyValueSource<K,V>
extends KeyValueSource<K,V>
implements IdentifiedDataSerializable, PartitionIdAware

This KeyValueSource implementation is used in KeyValueSource.fromMultiMap(com.hazelcast.core.MultiMap) to generate a default implementation based on a Hazelcast MultiMap.

Constructor Summary

Constructors

Constructor and Description
MultiMapKeyValueSource(String multiMapName)

Method Summary

Modifier and Type	Method and Description
void	close()
Map.Entry<K,V>	element() Returns the current index' element
int	getFactoryId()
int	getId()
boolean	hasNext() Called to request if at least one more key-value pair is available from this data source.
K	key() Returns the current index' key for KeyPredicate analysis.
boolean	open(NodeEngine nodeEngine) This method is called before accessing the key-value pairs of this KeyValueSource
void	readData(ObjectDataInput in)
boolean	reset() This method need to reset all internal state as it would be a new instance at all.
void	setPartitionId(int partitionId) Sets the partition id the implementing instance is executed against
void	writeData(ObjectDataOutput out)

Methods inherited from class com.hazelcast.mapreduce.KeyValueSource

fromList, fromMap, fromMultiMap, fromSet, getAllKeys, getAllKeys0, isAllKeysSupported

Methods inherited from class java.lang.Object

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

Constructor Detail

MultiMapKeyValueSource

public MultiMapKeyValueSource(String multiMapName)

Method Detail

open

public boolean open(NodeEngine nodeEngine)

Description copied from class: KeyValueSource

This method is called before accessing the key-value pairs of this KeyValueSource

Specified by:

open in class KeyValueSource<K,V>

Parameters:

nodeEngine - nodeEngine of this cluster node

Returns:

true if operation succeed otherwise false

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException

hasNext

public boolean hasNext()

Description copied from class: KeyValueSource

Called to request if at least one more key-value pair is available from this data source. If so this method returns true otherwise it false.

Specified by:

hasNext in class KeyValueSource<K,V>

Returns:

true if at least one more value is available otherwise false

key

public K key()

Description copied from class: KeyValueSource

Returns the current index' key for KeyPredicate analysis. This is called to prevent a possible deserialization of unneeded values because the key is not interesting for the running mapreduce algorithm.

Specified by:

key in class KeyValueSource<K,V>

Returns:

current index' key

element

public Map.Entry<K,V> element()

Description copied from class: KeyValueSource

Returns the current index' element

Specified by:

element in class KeyValueSource<K,V>

Returns:

current index' element

reset

public boolean reset()

Description copied from class: KeyValueSource

This method need to reset all internal state as it would be a new instance at all. The same instance of the KeyValueSource may be used multiple times in a row depending on the internal implementation, especially when the KeyValueSource implements PartitionIdAware.
If the instance is reused a sequence of KeyValueSource.reset(), KeyValueSource.open(com.hazelcast.spi.NodeEngine) and Closeable.close() is called multiple times with the other methods between open(...) and close().

Specified by:

reset in class KeyValueSource<K,V>

Returns:

true if reset was successful otherwise false

setPartitionId

public void setPartitionId(int partitionId)

Description copied from interface: PartitionIdAware

Sets the partition id the implementing instance is executed against

Specified by:

setPartitionId in interface PartitionIdAware

Parameters:

partitionId - current partitionId

writeData

public void writeData(ObjectDataOutput out)
               throws IOException

Specified by:

writeData in interface DataSerializable

Throws:

IOException

readData

public void readData(ObjectDataInput in)
              throws IOException

Specified by:

readData in interface DataSerializable

Throws:

IOException

getFactoryId

public int getFactoryId()

Specified by:

getFactoryId in interface IdentifiedDataSerializable

getId

public int getId()

Specified by:

getId in interface IdentifiedDataSerializable