Package com.hazelcast.jet.core

Class Vertex

  • All Implemented Interfaces:
    DataSerializable, IdentifiedDataSerializable
    public class Vertex
extends java.lang.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 Detail

    • Constructor Detail

      • Vertex

        public Vertex​(@Nonnull
              java.lang.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
              java.lang.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
              java.lang.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 java.lang.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
                               java.util.function.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 java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • writeData

        public void writeData​(@Nonnull
                      ObjectDataOutput out)
               throws java.io.IOException
        Description copied from interface: DataSerializable
        Writes object fields to output stream
        Specified by:
        writeData in interface DataSerializable
        Parameters:
        out - output
        Throws:
        java.io.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 java.io.IOException
        Description copied from interface: DataSerializable
        Reads fields from the input stream
        Specified by:
        readData in interface DataSerializable
        Parameters:
        in - input
        Throws:
        java.io.IOException - if an I/O error occurs. In particular, an IOException may be thrown if the input stream has been closed.