com.hazelcast.jet.core

Class Vertex

java.lang.Object

com.hazelcast.jet.core.Vertex

All Implemented Interfaces:

DataSerializable, IdentifiedDataSerializable

public class Vertex
extends Object
implements IdentifiedDataSerializable

Represents a unit of data processing in a Jet computation job. Conceptually, a vertex receives data items over its inbound edges and pushes data items to its outbound edges. Practically, a single vertex is represented by a set of instances of Processor. The localParallelism property determines the number of processor instances running on each cluster member.

Each processor is assigned a set of partition IDs it is responsible for. When an inbound edge is partitioned, the processor will receive only those data items whose partition ID it is responsible for. For data traveling over a partitioned edge which is also distributed, the whole cluster contains a single unique processor instance responsible for any given partition ID. For non-distributed edges, the processor is unique only within a member and each member has its own processor for any given partition ID. Finally, there is a guarantee of collation across all the partitioned edges impinging on a vertex: within each member, all the data with a given partition ID is received by the same processor.

A vertex is uniquely identified in a DAG by its name.

Since:

Jet 3.0

Field Summary

Fields

Modifier and Type	Field and Description
static int	LOCAL_PARALLELISM_USE_DEFAULT The value of localParallelism(int) with the meaning "use the default local parallelism".

Constructor Summary

Constructors

Constructor and Description
Vertex(String name, ProcessorMetaSupplier metaSupplier) Creates a vertex from a ProcessorMetaSupplier.
Vertex(String name, ProcessorSupplier processorSupplier) Creates a vertex from a ProcessorSupplier.
Vertex(String name, SupplierEx<? extends Processor> processorSupplier) Creates a vertex from a Supplier<Processor>.

Method Summary

Modifier and Type	Method and Description
static int	checkLocalParallelism(int parallelism) Says whether the given integer is valid as the value of localParallelism.
int	determineLocalParallelism(int defaultParallelism) Determines the local parallelism value for the vertex by looking at its local parallelism and meta supplier's preferred local parallelism.
int	getClassId() Returns type identifier for this class.
int	getFactoryId() Returns DataSerializableFactory factory ID for this class.
int	getLocalParallelism() Returns the number of processors corresponding to this vertex that will be created on each member.
ProcessorMetaSupplier	getMetaSupplier() Returns this vertex's meta-supplier of processors.
String	getName() Returns the name of this vertex.
Vertex	localParallelism(int localParallelism) Sets the number of processors corresponding to this vertex that will be created on each member.
void	readData(ObjectDataInput in) Reads fields from the input stream
String	toString()
void	updateMetaSupplier(UnaryOperator<ProcessorMetaSupplier> updateFn) Applies the provided operator function to the current processor meta-supplier and replaces it with the one it returns.
void	writeData(ObjectDataOutput out) Writes object fields to output stream

Methods inherited from class java.lang.Object

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

Field Detail

LOCAL_PARALLELISM_USE_DEFAULT

public static final int LOCAL_PARALLELISM_USE_DEFAULT

The value of localParallelism(int) with the meaning "use the default local parallelism".

See Also:

Constant Field Values

Constructor Detail

Vertex

public Vertex(@Nonnull
              String name,
              @Nonnull
              SupplierEx<? extends Processor> processorSupplier)

Creates a vertex from a Supplier<Processor>.

This is useful for vertices where all the Processor instances will be instantiated the same way.

NOTE: this constructor should not be abused with a stateful implementation which produces a different processor each time. In such a case the full ProcessorSupplier type should be implemented.

Parameters:

name - the unique name of the vertex. This name identifies the vertex in the snapshot

processorSupplier - the simple, parameterless supplier of Processor instances

Vertex

public Vertex(@Nonnull
              String name,
              @Nonnull
              ProcessorSupplier processorSupplier)

Creates a vertex from a ProcessorSupplier.

Parameters:

name - the unique name of the vertex. This name identifies the vertex in the snapshot

processorSupplier - the supplier of Processor instances which will be used on all members

Vertex

public Vertex(@Nonnull
              String name,
              @Nonnull
              ProcessorMetaSupplier metaSupplier)

Creates a vertex from a ProcessorMetaSupplier.

Parameters:

name - the unique name of the vertex. This name identifies the vertex in the snapshot

metaSupplier - the meta-supplier of ProcessorSuppliers for each member

Method Detail

checkLocalParallelism

public static int checkLocalParallelism(int parallelism)

Says whether the given integer is valid as the value of localParallelism.

determineLocalParallelism

public int determineLocalParallelism(int defaultParallelism)

Determines the local parallelism value for the vertex by looking at its local parallelism and meta supplier's preferred local parallelism.

If none of them is set, returns the provided default parallelism

localParallelism

@Nonnull
public Vertex localParallelism(int localParallelism)

Sets the number of processors corresponding to this vertex that will be created on each member.

If the value is -1, Jet will determine the vertex's local parallelism during job initialization from the global default and processor meta-supplier's preferred value.

getLocalParallelism

public int getLocalParallelism()

Returns the number of processors corresponding to this vertex that will be created on each member. A value of -1 means that this property is not set; in that case the default configured on the Jet instance will be used.

getName

@Nonnull
public String getName()

Returns the name of this vertex.

getMetaSupplier

@Nonnull
public ProcessorMetaSupplier getMetaSupplier()

Returns this vertex's meta-supplier of processors.

updateMetaSupplier

public void updateMetaSupplier(@Nonnull
                               UnaryOperator<ProcessorMetaSupplier> updateFn)

Applies the provided operator function to the current processor meta-supplier and replaces it with the one it returns. Typically used to decorate the existing meta-supplier.

toString

public String toString()

Overrides:

toString in class Object

writeData

public void writeData(@Nonnull
                      ObjectDataOutput out)
               throws IOException

Description copied from interface: DataSerializable

Writes object fields to output stream

Specified by:

writeData in interface DataSerializable

Parameters:

out - output

Throws:

IOException - if an I/O error occurs. In particular, an IOException may be thrown if the output stream has been closed.

readData

public void readData(@Nonnull
                     ObjectDataInput in)
              throws IOException

Description copied from interface: DataSerializable

Reads fields from the input stream

Specified by:

readData in interface DataSerializable

Parameters:

in - input

Throws:

IOException - if an I/O error occurs. In particular, an IOException may be thrown if the input stream has been closed.

getFactoryId

public int getFactoryId()

Description copied from interface: IdentifiedDataSerializable

Returns DataSerializableFactory factory ID for this class.

Specified by:

getFactoryId in interface IdentifiedDataSerializable

Returns:

factory ID

getClassId

public int getClassId()

Description copied from interface: IdentifiedDataSerializable

Returns type identifier for this class. It should be unique per DataSerializableFactory.

Specified by:

getClassId in interface IdentifiedDataSerializable

Returns:

type ID