## org.ggf.drmaa
Interface Session

All Known Implementing Classes:
  SessionImpl

public interface Session

This interface represents a the operations available for interacting with the DRM. In DRMAA, (almost) all DRM interaction occur within the context of a session. The spec also strongly recommends that a DRMAA implementation not allow concurrent sessions. Since DRMAA has no facility for user authentication or authorization, most DRMAA implementations will likely only support one session per implementation instance.

In order to use a Session, it must first be initialized. Once initialized it is the responsibility of the programmer to ensure that the session also be explicitly terminated. Otherwise, session artifacts may be left behind on the client and/or server. A handy way to make sure the Session is terminated is to set up a shutdown hook to call the exit() method on the active session.

To get a Session implementation appropriate for the DRM in use, one uses the SessionFactory.getSession() method.

Example:

    public static void main (String[] args) throws Exception {
       SessionFactory factory = SessionFactory.getFactory ();
       Session session = factory.getSession ();

       try {
          session.init (null);
          JobTemplate jt = session.createJobTemplate ();
          jt.setRemoteCommand ("sleeper.sh");
          jt.setArgs (new String[] {"5"});

          String id = session.runJob (jt);

          session.deleteJobTemplate (jt);

          while (session.getJobProgramStatus (id) != Session.RUNNING) {
             Thread.sleep (1000);
          }

          System.out.println ("Job " + id + " is now running.");

          session.control (id, Session.SUSPEND);
          Thread.sleep (1000);
          session.control (id, Session.RELEASE);

          JobInfo info = session.wait (id, Session.TIMEOUT_WAIT_FOREVER);

          System.out.println ("Job " + info.getJobId () + " exited with status: " +
                              info.getExitStatus ());

          session.exit ();
       }
       catch (DrmaaException e) {
          System.out.println ("Error: " + e.getMessage ());
       }
     }

Since:
  0.5
Author:
  dan.templeton@sun.com
See Also:
  `Runtime.addShutdownHook(java.lang.Thread)`, `SessionFactory`, Grid Engine DRMAA Java[TM] Language Binding HowTo

Field Summary
`static int` `DONE` Job has finished normally
`static int` `FAILED` Job finished, but terminated abnormally
`static int` `HOLD` Put the job on hold
`static java.lang.String` `JOB_IDS_SESSION_ALL` All jobs submitted during this DRMAA session
`static java.lang.String` `JOB_IDS_SESSION_ANY` Any job from the session
`static int` `QUEUED_ACTIVE` Job is queued and active
`static int` `RELEASE` Release the hold on the job
`static int` `RESUME` Resume the job
`static int` `RUNNING` Job is running
`static int` `SUSPEND` Suspend the job
`static int` `SYSTEM_ON_HOLD` Job is queued and in system hold
`static int` `SYSTEM_SUSPENDED` Job is system suspended
`static int` `TERMINATE` Kill the job
`static long` `TIMEOUT_NO_WAIT` Return immediately if no result is available
`static long` `TIMEOUT_WAIT_FOREVER` Wait indefinitely for a result
`static int` `UNDETERMINED` Job status cannot be determined
`static int` `USER_ON_HOLD` Job is queued and in user hold
`static int` `USER_SUSPENDED` Job is user suspended
`static int` `USER_SYSTEM_ON_HOLD` Job is queued and in user and system hold
`static int` `USER_SYSTEM_SUSPENDED` Job is user suspended

Method Summary
`void` `control(java.lang.String jobId, int action)` Hold, release, suspend, resume, or kill the job identified by jobId.
`JobTemplate` `createJobTemplate()` Get a new job template.
`void` `deleteJobTemplate(JobTemplate jt)` Deallocate a job template.
`void` `exit()` Disengage from DRM and allow the DRMAA implementation to perform any necessary internal cleanup.
`java.lang.String` `getContact()` If called before init(), this method returns a comma delimited String containing the contact Strings available from the default DRMAA implementation, one element per DRM system available.
`java.lang.String` `getDrmaaImplementation()` If called before init(), this method returns a comma delimited list of DRMAA implementations, one element for each DRMAA implementation provided.
`java.lang.String` `getDrmSystem()` If called before init(), this method returns a comma delimited list of DRM systems, one element per DRM system implementation provided.
`int` `getJobProgramStatus(java.lang.String jobId)` Get the program status of the job identified by jobId.
`Version` `getVersion()` Returns a Version object containing the major and minor version numbers of the DRMAA library.
`void` `init(java.lang.String contact)` Initialize the DRMAA implementation.
`java.util.List` `runBulkJobs(JobTemplate jt, int start, int end, int incr)` Submit a set of parametric jobs, dependent on the implied loop index, each with attributes defined in the job template, jt.
`java.lang.String` `runJob(JobTemplate jt)` Submit a job with attributes defined in the job template, jt.
`void` `synchronize(java.util.List jobIds, long timeout, boolean dispose)` Wait until all jobs specified by jobIds have finished execution.
`JobInfo` `wait(java.lang.String jobId, long timeout)` This method will wait for a job with jobId to finish execution or fail.

Field Detail

### SUSPEND

    public static final int SUSPEND

  Suspend the job

  See Also:
    Constant Field Values

### RESUME

    public static final int RESUME

  Resume the job

  See Also:
    Constant Field Values

### HOLD

    public static final int HOLD

  Put the job on hold

  See Also:
    Constant Field Values

### RELEASE

    public static final int RELEASE

  Release the hold on the job

  See Also:
    Constant Field Values

### TERMINATE

    public static final int TERMINATE

  Kill the job

  See Also:
    Constant Field Values

### JOB_IDS_SESSION_ALL

    public static final java.lang.String JOB_IDS_SESSION_ALL

  All jobs submitted during this DRMAA session

  See Also:
    Constant Field Values

### JOB_IDS_SESSION_ANY

    public static final java.lang.String JOB_IDS_SESSION_ANY

  Any job from the session

  See Also:
    Constant Field Values

### TIMEOUT_WAIT_FOREVER

    public static final long TIMEOUT_WAIT_FOREVER

  Wait indefinitely for a result

  See Also:
    Constant Field Values

### TIMEOUT_NO_WAIT

    public static final long TIMEOUT_NO_WAIT

  Return immediately if no result is available

  See Also:
    Constant Field Values

### UNDETERMINED

    public static final int UNDETERMINED

  Job status cannot be determined

  See Also:
    Constant Field Values

### QUEUED_ACTIVE

    public static final int QUEUED_ACTIVE

  Job is queued and active

  See Also:
    Constant Field Values

### SYSTEM_ON_HOLD

    public static final int SYSTEM_ON_HOLD

  Job is queued and in system hold

  See Also:
    Constant Field Values

### USER_ON_HOLD

    public static final int USER_ON_HOLD

  Job is queued and in user hold

  See Also:
    Constant Field Values

### USER_SYSTEM_ON_HOLD

    public static final int USER_SYSTEM_ON_HOLD

  Job is queued and in user and system hold

  See Also:
    Constant Field Values

### RUNNING

    public static final int RUNNING

  Job is running

  See Also:
    Constant Field Values

### SYSTEM_SUSPENDED

    public static final int SYSTEM_SUSPENDED

  Job is system suspended

  See Also:
    Constant Field Values

### USER_SUSPENDED

    public static final int USER_SUSPENDED

  Job is user suspended

  See Also:
    Constant Field Values

### USER_SYSTEM_SUSPENDED

    public static final int USER_SYSTEM_SUSPENDED

  Job is user suspended

  See Also:
    Constant Field Values

### DONE

    public static final int DONE

  Job has finished normally

  See Also:
    Constant Field Values

### FAILED

    public static final int FAILED

  Job finished, but terminated abnormally

  See Also:
    Constant Field Values

Method Detail

### init

    public void init(java.lang.String contact)
              throws DrmaaException

  Initialize the DRMAA implementation. contact is an implementation-dependent string that may be used to specify which DRM system to use. This routine must be called before any other DRMAA calls, except for getVersion(), getDRMSystem(), getDRMAAImplementation(), or getContact().

  If contact is `null`, the default DRM system is used, provided there is only one DRMAA implementation in the module. If there is more than one DRMAA implementation in the module, init() throws a NoDefaultContactStringSelectedException. init() should be called only once, by only one of the threads. The main thread is recommended. A call to init() by another thread or additional calls to init() by the same thread with throw a SessionAlreadyActiveException.

  Parameters:
    `contact` - implementation-dependent string that may be used to specify which DRM system to use. If null, will select the default DRM if there is only one DRMAA implementation available.
  Throws:
    `DrmaaException` - May be be one of the following:
    - InvalidContactStringException
    - AlreadyActiveSessionException
    - DefaultContactStringException
    - NoDefaultContactStringSelectedException

### exit

    public void exit()
              throws DrmaaException

  Disengage from DRM and allow the DRMAA implementation to perform any necessary internal cleanup. This routine ends the current DRMAA session but doesn't affect any jobs (e.g., queued and running jobs remain queued and running). exit() should be called only once, by only one of the threads. Additional calls to exit() beyond the first will throw a NoActiveSessionException.

  Throws:
    `DrmaaException` - May be one of the following:
    - DrmsExitException
    - NoActiveSessionException

### createJobTemplate

    public JobTemplate createJobTemplate()
                                  throws DrmaaException

  Get a new job template. The job template is used to set the environment for jobs to be submitted. Once the job template has been created, it should also be deleted (via deleteJobTemplate()) when no longer needed. Failure to do so may result in a memory leak.

  Returns:
    a blank JobTemplate object
  Throws:
    `DrmaaException` - May be one of the following:
    - DrmCommunicationException
  See Also:
    `JobTemplate`

### deleteJobTemplate

    public void deleteJobTemplate(JobTemplate jt)
                           throws DrmaaException

  Deallocate a job template. This routine has no effect on running jobs.

  Parameters:
    `jt` - the JobTemplate to delete
  Throws:
    `DrmaaException` - May be one of the following:
    - DrmCommunicationException
    - InvalidJobTemplateException

### runJob

    public java.lang.String runJob(JobTemplate jt)
                            throws DrmaaException

  Submit a job with attributes defined in the job template, jt. The returned job identifier is a String identical to that returned from the underlying DRM system.

  Parameters:
    `jt` - the job template to be used to create the job
  Returns:
    job identifier String identical to that returned from the underlying DRM system
  Throws:
    `DrmaaException` - May be one of the following:
    - TryLaterException
    - DeniedByDrmException
    - DrmCommunicationException
    - AuthorizationException
    - InvalidJobTemplateException

### runBulkJobs

    public java.util.List runBulkJobs(JobTemplate jt,
                                      int start,
                                      int end,
                                      int incr)
                               throws DrmaaException

  Submit a set of parametric jobs, dependent on the implied loop index, each with attributes defined in the job template, jt. The returned job identifiers are Strings identical to those returned from the underlying DRM system.

  The JobTemplate class defines a `PARAMETRIC_INDEX` placeholder for use in specifying paths. This placeholder is used to represent the individual identifiers of the tasks submitted through this method.

  Parameters:
    `start` - the starting value for the loop index
    `end` - the terminating value for the loop index
    `incr` - the value by which to increment the loop index each iteration
    `jt` - the job template to be used to create the job
  Returns:
    job identifier Strings identical to that returned by the underlying DRM system
  Throws:
    `DrmaaException` - May be one of the following:
    - TryLaterException
    - DeniedByDrmException
    - DrmCommunicationException
    - AuthorizationException
    - InvalidJobTemplateException

### control

    public void control(java.lang.String jobId,
                        int action)
                 throws DrmaaException

  Hold, release, suspend, resume, or kill the job identified by jobId. If jobId is `JOB_IDS_SESSION_ALL`, then this routine acts on all jobs submitted during this DRMAA session up to the moment control() is called. To avoid thread races in multithreaded applications, the DRMAA implementation user should explicitly synchronize this call with any other job submission calls or control calls that may change the number of remote jobs.

  The legal values for action and their meanings are:

  - `SUSPEND`: stop the job,
  - `RESUME`: (re)start the job,
  - `HOLD`: put the job on-hold,
  - `RELEASE`: release the hold on the job, and
  - `TERMINATE`: kill the job.

  This method returns once the action has been acknowledged by the DRM system, but does not necessarily wait until the action has been completed.

  Some DRMAA implementations may allow this method to be used to control jobs submitted external to the DRMAA session, such as jobs submitted by other DRMAA session in other DRMAA implementations or jobs submitted via native utilities.

  Parameters:
    `jobId` - The id of the job to control
    `action` - the control action to be taken
  Throws:
    `DrmaaException` - May be one of the following:
    - DrmCommunicationException
    - AuthorizationException
    - ResumeInconsistentStateException
    - SuspendInconsistentStateException
    - HoldInconsistentStateException
    - ReleaseInconsistentStateException
    - InvalidJobException

### synchronize

    public void synchronize(java.util.List jobIds,
                            long timeout,
                            boolean dispose)
                     throws DrmaaException

  Wait until all jobs specified by jobIds have finished execution. If jobIds contains `JOB_IDS_SESSION_ALL`, then this method waits for all jobs submitted during this DRMAA session up to the moment synchronize() is called. To avoid thread race conditions in multithreaded applications, the DRMAA implementation user should explicitly synchronize this call with any other job submission calls or control calls that may change the number of remote jobs.

  To prevent blocking indefinitely in this call, the caller may use a timeout specifying after how many seconds to block in this call. The value `TIMEOUT_WAIT_FOREVER MAY` be specified to wait indefinitely for a result. The value `TIMEOUT_NO_WAIT MAY` be specified to return immediately if no result is available. If the call exits before the timeout has elapsed, all the jobs have been waited on or there was an interrupt. If the invocation exits on timeout, an ExitTimeException is thrown. The caller should check system time before and after this call in order to be sure of how much time has passed.

  The dispose parameter specifies how to treat the reaping of the remote job's internal data record, which includes a record of the job's consumption of system resources during its execution and other statistical information. If set to `true`, the DRM will dispose of the job's data record at the end of the synchroniize() call. If set to `false`, the data record will be left for future access via the wait() method.

  Parameters:
    `jobIds` - the ids of the jobs to synchronize
    `timeout` - the maximum number of seconds to wait
    `dispose` - specifies how to treat reaping information
  Throws:
    `DrmaaException` - May be one of the following:
    - DrmCommunicationException
    - AuthorizationException
    - ExitTimeoutException
    - InvalidJobException
  See Also:
    `wait(java.lang.String, long)`

### wait

    public JobInfo wait(java.lang.String jobId,
                        long timeout)
                 throws DrmaaException

  This method will wait for a job with jobId to finish execution or fail. If the special string, `JOB_IDS_SESSION_ANY`, is provided as the jobId, this routine will wait for any job from the session. This routine is modeled on the wait3 POSIX routine.

  The timeout value is used to specify the desired behavior when a result is not immediately available. The value, `TIMEOUT_WAIT_FOREVER`, may be specified to wait indefinitely for a result. The value, `TIMEOUT_NO_WAIT`, may be specified to return immediately if no result is available. Alternatively, a number of seconds may be specified to indicate how long to wait for a result to become available.````

  If the call exits before timeout, either the job has been waited on successfully or there was an interrupt. If the invocation exits on timeout, an ExitTimeoutException is thrown. The caller should check system time before and after this call in order to be sure how much time has passed.

  The routine reaps job data records on a successful call, so any subsequent calls to wait() will fail, throwing an InvalidJobException, meaning that the job's data record has been already reaped. This exception is the same as if the job was unknown. (The only case where wait() can be successfully called on a single job more than once is when the previous call to wait() timed out before the job finished.)

  When successful, the resource usage information for the job is provided as a Map of usage parameter names and their values. The values contain the amount of resources consumed by the job and are implementation defined.

  Parameters:
    `jobId` - the id of the job for which to wait
    `timeout` - the maximum number of seconds to wait
  Returns:
    the resource usage and status information
  Throws:
    `DrmaaException` - May be one of the following:
    - DrmCommunicationException
    - AuthorizationException
    - NoResourceUsageDataException
    - ExitTimeoutException
    - InvalidJobException

### getJobProgramStatus

    public int getJobProgramStatus(java.lang.String jobId)
                            throws DrmaaException

  Get the program status of the job identified by jobId. The possible values returned from this method are:
  - `UNDETERMINED`: process status cannot be determined
  - `QUEUED_ACTIVE`: job is queued and active
  - `SYSTEM_ON_HOLD`: job is queued and in system hold
  - `USER_ON_HOLD`: job is queued and in user hold
  - `USER_SYSTEM_ON_HOLD`: job is queued and in user and system hold
  - `RUNNING`: job is running
  - `SYSTEM_SUSPENDED`: job is system suspended
  - `USER_SUSPENDED`: job is user suspended
  - `DONE`: job finished normally
  - `FAILED`: job finished, but failed.
  The DRMAA implementation should always get the status of jobId from DRM system unless the status has already been determined to be `FAILED` or `DONE` and the status has been successfully cached. Terminated jobs return a `FAILED` status.

  Parameters:
    `jobId` - the id of the job whose status is to be retrieved
  Returns:
    the program status
  Throws:
    `DrmaaException` - May be one of the following:
    - DrmCommunicationException
    - AuthorizationException
    - InvalidJobException

### getContact

    public java.lang.String getContact()

  If called before init(), this method returns a comma delimited String containing the contact Strings available from the default DRMAA implementation, one element per DRM system available. If called after init(), this method returns the contact String for the DRM system to which the session is attached. The returned String is implementation dependent.

  Returns:
    current contact information for DRM system or a comma delimited list of possible contact Strings

### getVersion

    public Version getVersion()

  Returns a Version object containing the major and minor version numbers of the DRMAA library. For DRMAA 0.5, major is 0 and minor is 5.

  Returns:
    the version number as a Version object
  See Also:
    `Version`

### getDrmSystem

    public java.lang.String getDrmSystem()

  If called before init(), this method returns a comma delimited list of DRM systems, one element per DRM system implementation provided. If called after init(), this method returns the selected DRM system. The returned String is implementation dependent.

  Returns:
    DRM system implementation information

### getDrmaaImplementation

    public java.lang.String getDrmaaImplementation()

  If called before init(), this method returns a comma delimited list of DRMAA implementations, one element for each DRMAA implementation provided. If called after init(), this method returns the selected DRMAA implementation. The returned String is implementation dependent and may contain the DRM system as a component.

  Returns:
    DRMAA implementation information