Package com.hazelcast.jet

Interface JetService

  • All Known Subinterfaces:
    JetInstance
    public interface JetService
    Jet is a component of Hazelcast to execute streaming or batch computations.
    Since:
    5.0

    • Method Detail

      • getConfig

        @Nonnull
JetConfig getConfig()
        Returns the configuration for this Jet member. This method is not available on client instances.

      • newJob

        @Nonnull
default Job newJob​(@Nonnull
                   DAG dag)
        Creates and returns a Jet job based on the supplied DAG. Jet will asynchronously start executing the job.

      • newJob

        @Nonnull
default Job newJob​(@Nonnull
                   Pipeline pipeline)
        Creates and returns an executable job based on the supplied pipeline. Jet will asynchronously start executing the job.

      • newJob

        @Nonnull
Job newJob​(@Nonnull
           DAG dag,
           @Nonnull
           JobConfig config)
        Creates and returns a Jet job based on the supplied DAG and job configuration. Jet will asynchronously start executing the job.

        If the name in the JobConfig is non-null, Jet checks if there is an active job with equal name, in which case it throws JobAlreadyExistsException. Job is active if it is running, suspended or waiting to be run; that is it has not completed or failed. Thus, there can be at most one active job with a given name at a time, and you can re-use the job name after the previous job completed.

        See also newJobIfAbsent(com.hazelcast.jet.core.DAG, com.hazelcast.jet.config.JobConfig).

        Throws:
        JobAlreadyExistsException - if there is an active job with an equal name

      • newJob

        @Nonnull
Job newJob​(@Nonnull
           Pipeline pipeline,
           @Nonnull
           JobConfig config)
        Creates and returns a Jet job based on the supplied pipeline and job configuration. Jet will asynchronously start executing the job.

        If the name in the JobConfig is non-null, Jet checks if there is an active job with equal name, in which case it throws JobAlreadyExistsException. Job is active if it is running, suspended or waiting to be run; that is it has not completed or failed. Thus, there can be at most one active job with a given name at a time, and you can re-use the job name after the previous job completed.

        See also newJobIfAbsent(com.hazelcast.jet.core.DAG, com.hazelcast.jet.config.JobConfig).

        Throws:
        JobAlreadyExistsException - if there is an active job with an equal name

      • newJobIfAbsent

        @Nonnull
Job newJobIfAbsent​(@Nonnull
                   DAG dag,
                   @Nonnull
                   JobConfig config)
        Creates and returns a Jet job based on the supplied DAG and job configuration. Jet will asynchronously start executing the job.

        If the name in the JobConfig is non-null, Jet checks if there is an active job with equal name. If there is, it will join that job instead of submitting a new one. Job is active if it is running, suspended or waiting to be run; that is it has not completed or failed. In other words, this method ensures that the job with this name is running and is not running multiple times in parallel.

        This method is useful for microservices deployment when each package contains a jet member and the job, and you want the job to run only once. But if the job is a batch job and runs very quickly, it can happen that it executes multiple times, because the job name can be reused after a previous execution completed.

        If the job name is null, a new job is always submitted.

        See also newJob(com.hazelcast.jet.core.DAG).

      • newJobIfAbsent

        @Nonnull
Job newJobIfAbsent​(@Nonnull
                   Pipeline pipeline,
                   @Nonnull
                   JobConfig config)
        Creates and returns a Jet job based on the supplied pipeline and job configuration. Jet will asynchronously start executing the job.

        If the name in the JobConfig is non-null, Jet checks if there is an active job with equal name. If there is, it will join that job instead of submitting a new one. Job is active if it is running, suspended or waiting to be run; that is it has not completed or failed. In other words, this method ensures that the job with this name is running and is not running multiple times in parallel.

        This method is useful for microservices deployment when each package contains a jet member and the job, and you want the job to run only once. But if the job is a batch job and runs very quickly, it can happen that it executes multiple times, because the job name can be reused after a previous execution completed.

        If the job name is null, a new job is always submitted.

        See also newJob(com.hazelcast.jet.core.DAG).

      • newLightJob

        Job newLightJob​(@Nonnull
                Pipeline p,
                @Nonnull
                JobConfig config)
        Submits a light job for execution. This kind of job is focused on reducing the job startup and teardown time: only a single operation is used to deploy the job instead of 2 for normal jobs.

        Limitations of light jobs:

        • very limited job configuration: no processing guarantee, no custom classes or job resources - all job code must be available in the cluster. Refer to JobConfig for details.
        • metrics not available through Job.getMetrics(). However, light jobs are included in member metrics accessed through other means.
        • failures will be only reported to the caller and logged in the cluster logs, but no trace of the job will remain in the cluster after it's done
        • RestartableException doesn't restart the job, but it will fail

        It substantially reduces the overhead for jobs that take milliseconds to complete.

        A light job will not be cancelled if the client disconnects. Its potential failure will be only logged in member logs.

        You should not mutate the JobConfig or Pipeline instances after submitting them to this method.

      • newLightJob

        @Nonnull
default Job newLightJob​(@Nonnull
                        DAG dag)
        Submits a job defined in the Core API with a default config.

        See newLightJob(Pipeline, JobConfig) for more information.

      • getJobs

        @Nonnull
java.util.List<Job> getJobs()
        Returns all submitted jobs. The result includes completed normal jobs, but doesn't include completed light jobs - for light jobs the cluster doesn't retain any information after they complete.

      • getJob

        @Nullable
Job getJob​(long jobId)
        Returns the job with the given id or null if no such job could be found.

      • getJobs

        @Nonnull
java.util.List<Job> getJobs​(@Nonnull
                            java.lang.String name)
        Returns all jobs submitted with the given name, ordered in descending order by submission time. The active job is always first. Empty list will be returned if no job with the given name exists. The list includes completed jobs.

      • getJob

        @Nullable
default Job getJob​(@Nonnull
                   java.lang.String name)
        Returns the active or last submitted job with the given name or null if no such job could be found. The returned job can be already completed.

      • getJobStateSnapshot

        @Nullable
JobStateSnapshot getJobStateSnapshot​(@Nonnull
                                     java.lang.String name)
        Returns the JobStateSnapshot object representing an exported snapshot with the given name. Returns null if no such snapshot exists.

      • getJobStateSnapshots

        @Nonnull
java.util.Collection<JobStateSnapshot> getJobStateSnapshots()
        Returns the collection of exported job state snapshots stored in the cluster.

      • getObservable

        @Nonnull
<T> Observable<T> getObservable​(@Nonnull
                                java.lang.String name)
        Returns an Observable instance with the specified name. Represents a flowing sequence of events produced by jobs containing observable sinks.

        Multiple calls of this method with the same name return the same instance (unless it was destroyed in the meantime).

        In order to observe the events register an Observer on the Observable.

        Parameters:
        name - name of the observable
        Returns:
        observable with the specified name
        Since:
        Jet 4.0

      • newObservable

        @Nonnull
default <T> Observable<T> newObservable()
        Returns a new observable with a randomly generated name
        Since:
        Jet 4.0

      • getObservables

        @Nonnull
java.util.Collection<Observable<?>> getObservables()
        Returns a list of all the Observables that are active. By "active" we mean that their backing Ringbuffer has been created, which happens when either their first Observer is registered or when the job publishing their data (via observable sinks) starts executing.
        Since:
        Jet 4.0