org.apache.giraph.function

Class ObjectTransfer<T>

java.lang.Object

org.apache.giraph.function.ObjectTransfer<T>

Type Parameters:

T - Type of object to transfer.

All Implemented Interfaces:

Serializable, Consumer<T>, Supplier<T>

public class ObjectTransfer<T>
extends Object
implements Supplier<T>, Consumer<T>

Default object transfer, intermediary between producers and consumers. Holds value temporarily in memory, so can be used only when producer and consumer are in the same context. Nulls it out after supplying, so each object is returned only once, and second consecutive call to 'get' will return null. Useful for both: - passing data from vertexReceive function of WorkerReceivePiece of previous Piece to vertexSend function WorkerSendPiece of next Piece, of the same vertex. - when value is set on the master, and later read in block logic (RepeatUntilBlock), or in a different Piece, either on worker or master. If it is read within the same piece - just use local field.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
ObjectTransfer() Constructor
ObjectTransfer(T value) Constructor

Method Summary

Modifier and Type	Method and Description
void	apply(T value) Applies this function to input
<I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable> ConsumerWithVertex<I,V,E,T>	castToConsumer() To be called when needing to pass it as a Consumer - making it obvious that K, V and E on consumer side can be any types, and to make code work without compile errors/warnings.
<I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable> SupplierFromVertex<I,V,E,T>	castToSupplier() To be called when needing to pass it as a Supplier - making it obvious that K, V and E on supplier side can be any types, and to make code work without compile errors/warnings.
T	get() Retrieves an instance of the appropriate type.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

ObjectTransfer

public ObjectTransfer(T value)

Constructor

Parameters:

value - initial value

ObjectTransfer

public ObjectTransfer()

Constructor

Method Detail

get

public T get()

Description copied from interface: Supplier

Retrieves an instance of the appropriate type. The returned object may or may not be a new instance, depending on the implementation.

Specified by:

get in interface Supplier<T>

Returns:

result

apply

public void apply(T value)

Description copied from interface: Consumer

Applies this function to input

Specified by:

apply in interface Consumer<T>

Parameters:

value - Input

toString

public String toString()

Overrides:

toString in class Object

castToSupplier

public <I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable> SupplierFromVertex<I,V,E,T> castToSupplier()

To be called when needing to pass it as a Supplier - making it obvious that K, V and E on supplier side can be any types, and to make code work without compile errors/warnings. In Java7, some callsites might need explicit types: object.<LongWritable, DoubleWritable, Writable>castToSupplier() In Java8, object.castToSupplier() is always going to be enough.

Type Parameters:

I - Vertex id type

V - Vertex value type

E - Edge value type

Returns:

supplier from vertex

castToConsumer

public <I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable> ConsumerWithVertex<I,V,E,T> castToConsumer()

To be called when needing to pass it as a Consumer - making it obvious that K, V and E on consumer side can be any types, and to make code work without compile errors/warnings. In Java7, some callsites might need explicit types: object.<LongWritable, DoubleWritable, Writable>castToConsumer() In Java8, object.castToConsumer() is always going to be enough.

Type Parameters:

I - Vertex id type

V - Vertex value type

E - Edge value type

Returns:

consumer with vertex