Interface JetInstance


public interface JetInstance
Represents either an instance of a Jet server node or a Jet client instance that connects to a remote cluster.
Since:
3.0
  • Method Details

    • getName

      @Nonnull String getName()
      Returns the name of the Jet instance.
    • getHazelcastInstance

      @Nonnull HazelcastInstance getHazelcastInstance()
      Returns the underlying Hazelcast IMDG instance used by Jet. It will be either a server node or a client, depending on the type of this JetInstance.
    • getCluster

      @Nonnull Cluster getCluster()
      Returns information about the cluster this Jet instance is part of.
    • 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).

    • getJobs

      @Nonnull List<Job> getJobs()
      Returns all submitted jobs including running and completed ones.
    • getJob

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

      @Nonnull List<Job> getJobs​(@Nonnull 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 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 default JobStateSnapshot getJobStateSnapshot​(@Nonnull String name)
      Returns the JobStateSnapshot object representing an exported snapshot with the given name. Returns null if no such snapshot exists.
    • getJobStateSnapshots

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

      @Nonnull <K,​ V> IMap<K,​V> getMap​(@Nonnull String name)
      Returns the distributed map instance with the specified name.

      It's possible to use the map as a data source or sink in a Jet Pipeline, using Sources.map(String) or Sinks.map(String) and the change stream of the map can be read using Sources.mapJournal(String, JournalInitialPosition).

      Parameters:
      name - name of the distributed map
      Returns:
      distributed map instance with the specified name
    • getReplicatedMap

      @Nonnull <K,​ V> ReplicatedMap<K,​V> getReplicatedMap​(@Nonnull String name)
      Returns the replicated map instance with the specified name.

      A replicated map can be used for enriching a stream, see GeneralStage.mapUsingReplicatedMap(String, FunctionEx, BiFunctionEx).

      Parameters:
      name - name of the distributed map
      Returns:
      distributed map instance with the specified name
    • getList

      @Nonnull <E> IList<E> getList​(@Nonnull String name)
      Returns the distributed list instance with the specified name.

      It's possible to use the link as a data source or sink in a Jet Pipeline, using Sources.list(String) or Sinks.list(String).

      Parameters:
      name - name of the distributed list
      Returns:
      distributed list instance with the specified name
    • getReliableTopic

      @Nonnull <E> ITopic<E> getReliableTopic​(@Nonnull String name)
      Returns a distributed reliable topic instance with the specified name.
      Parameters:
      name - name of the distributed topic
      Returns:
      distributed reliable topic instance with the specified name
      Since:
      4.0
    • getCacheManager

      @Nonnull JetCacheManager getCacheManager()
      Obtain the JetCacheManager that provides access to JSR-107 (JCache) caches configured on a Hazelcast Jet cluster.

      Note that this method does not return a JCache CacheManager

      Returns:
      the Hazelcast Jet JetCacheManager
      See Also:
      JetCacheManager
    • getObservable

      @Nonnull <T> Observable<T> getObservable​(@Nonnull 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:
      4.0
    • newObservable

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

      @Nonnull 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.
    • shutdown

      void shutdown()
      Shuts down the current instance. If this is a client instance, it disconnects the client. If this is a member instance, it gracefully terminates the jobs running on it and, if so configured, restarts them after this instance has shut down. When shutting down the entire cluster, it is a good practice to manually suspend all the jobs so that they don't get restarted multiple times as each member shuts down.

      The call blocks until the instance is actually down.

      Note: If you call this.getHazelcastInstance().shutdown(), it will cause all the jobs that run on this member to be forcefully terminated, without creating a terminal snapshot. After the cluster stabilizes again, Jet will restart them from the last snapshot that was created some time ago.