com.ibm.websphere.scheduler

Interface Scheduler


  • public interface Scheduler
    Scheduler is the central interface for managing and creating tasks.

    Instances of a Scheduler are defined using the administrative console, and located by performing a lookup in the WebSphere JNDI name space. For example:

    InitialContext ic = new InitialContext();
Scheduler scheduler = (Scheduler)ic.lookup("java:comp/env/Scheduler");
    (A resource reference to a scheduler is assumed to be bound to the name 'java:comp/env/Scheduler' here)

    Each Scheduler has an associated daemon thread that is responsible for executing tasks created within it's scope using the Scheduler.create method. Once tasks are created, the same application can then use the task's ID (retrieved from the create method's resulting TaskStatus) to cancel, suspend, resume or purge the task. Since all tasks are persistent, if the application server is restarted, the daemon for the Scheduler will automatically start and begin executing the tasks. Likewise, you can continue to lookup tasks previously created and view their status or alter their state.

    Since:
    5.0
    Version:
    5.0

    • Method Summary

      Methods 
      Modifier and Type Method and Description
      TaskStatus cancel(java.lang.String taskId, boolean purgeAlso)
      Cancels a task.
      TaskStatus create(TaskInfo taskInfo)
      Creates a task in the persistent store based upon the data found in the TaskInfo.
      BeanTaskInfo createBeanTaskInfo()
      Deprecated. 
      Use the createTaskInfo method.
      MessageTaskInfo createMessageTaskInfo()
      Deprecated. 
      Use the createTaskInfo method.
      java.lang.Object createTaskInfo(java.lang.Class taskInfoInterface)
      Creates an instance of the specified TaskInfo interface class.
      java.util.Iterator findTasksByName(java.lang.String name)
      Finds all TaskInfo records with a specified name that were created by the caller's application.
      TaskInfo[] findTasksByName(java.lang.String name, int beginIndex, int endIndex)
      Returns the subset of TaskInfo records between beginIndex and endIndex (0-based) that match the specified name and were created by the caller's application.
      java.util.Iterator findTaskStatusByName(java.lang.String name)
      Finds all TaskStatus records which have the specified name and were created by the caller's application.
      TaskStatus[] findTaskStatusByName(java.lang.String name, int beginIndex, int endIndex)
      Returns the subset of TaskStatus records between beginIndex and endIndex that match the specified name and were created by the caller's application.
      TaskStatus getStatus(java.lang.String taskId)
      Retrieves the current status of a task.
      TaskInfo getTask(java.lang.String taskId)
      Retrieves the current task.
      TaskStatus purge(java.lang.String taskId)
      Deletes a completed or cancelled task from the persistent store.
      TaskStatus resume(java.lang.String taskId)
      Resumes a suspended task.
      TaskStatus suspend(java.lang.String taskId)
      Suspends a task.

    • Method Detail

      • createBeanTaskInfo

        BeanTaskInfo createBeanTaskInfo()
        Deprecated. Use the createTaskInfo method.
        Creates an instance of BeanTaskInfo. Once created, use the BeanTaskInfo interface methods to configure the BeanTaskInfo and use the Scheduler.create method to schedule the BeanTaskInfo task.
        Since:
        5.0
        See Also:
        createTaskInfo(java.lang.Class), BeanTaskInfo

      • createMessageTaskInfo

        MessageTaskInfo createMessageTaskInfo()
        Deprecated. Use the createTaskInfo method.
        Creates an instance of MessageTaskInfo. Once created, use the MessageTaskInfo interface methods to configure the MessageTaskInfo and use the Scheduler.create method to schedule the MessageTaskInfo task.
        Since:
        5.0
        See Also:
        createTaskInfo(java.lang.Class), MessageTaskInfo

      • createTaskInfo

        java.lang.Object createTaskInfo(java.lang.Class taskInfoInterface)
                                throws TaskInfoInvalid
        Creates an instance of the specified TaskInfo interface class. Once created, use the associated methods on the interface to configure the TaskInfo and use the Scheduler.create method to schedule the task.

        For example: BeanTaskInfo myTask = (BeanTaskInfo)scheduler.createTaskInfo(BeanTaskInfo.class); myTask.setTaskHandler(myHandlerHome); scheduler.create(myTask);

        Parameters:
        taskInfoInterface - the interface of the TaskInfo implementation you would like to create.
        Returns:
        the instance of the specified interface.
        Throws:
        TaskInfoInvalid - the specified TaskInfo interface class is not available or registered.

      • cancel

        TaskStatus cancel(java.lang.String taskId,
                boolean purgeAlso)
                  throws SchedulerNotAvailableException,
                         TaskInvalid,
                         TaskPending,
                         NotificationException
        Cancels a task. When a task is cancelled, it remains in the persistent store until purged. In addition to the declared exceptions, it is also possible for this method to raise SchedulerRuntimeException, in which case the transaction is rolled back.
        Parameters:
        taskId - The Task ID of the task which is to be canceled.
        purgeAlso - Specifies that the task should be purged immediately.
        Returns:
        the current TaskStatus of the task.
        Throws:
        SchedulerNotAvailableException - Transaction is rolled-back or marked to roll-back. Thrown when there was a problem accessing the persistent store.
        TaskInvalid - No transaction rollback occurs. The task id is invalid or has been purged.
        TaskPending - No transaction rollback occurs. Thrown when another thread is currently modifying this row.
        NotificationException - No transaction rollback occurs. Thrown when the NotificationSink fails to fire due to an exception.
        Since:
        5.0
        See Also:
        TaskStatus.getTaskId()

      • suspend

        TaskStatus suspend(java.lang.String taskId)
                   throws SchedulerNotAvailableException,
                          TaskInvalid,
                          TaskPending,
                          IllegalTaskState,
                          NotificationException
        Suspends a task. A suspended task will not run until it has been resumed using the resume method. If the task is already in the suspended state, this has no effect.
        Parameters:
        taskId - The Task ID of the task to be suspended.
        Returns:
        the current TaskStatus of the task.
        Throws:
        SchedulerNotAvailableException - Transaction is rolled-back or marked to roll-back. Thrown when there was a problem accessing the persistent store.
        TaskInvalid - No transaction rollback occurs. The task id is invalid or has been purged.
        TaskPending - No transaction rollback occurs. Thrown when another thread is currently modifying this row.
        IllegalTaskState - No transaction rollback occurs. The task has been cancelled or completed. Cancelled and completed tasks cannot be suspended.
        NotificationException - No transaction rollback occurs. Thrown when the NotificationSink fails to fire due to an exception.
        Since:
        5.0
        See Also:
        TaskStatus.getTaskId()

      • resume

        TaskStatus resume(java.lang.String taskId)
                  throws SchedulerNotAvailableException,
                         TaskInvalid,
                         TaskPending,
                         IllegalTaskState,
                         NotificationException
        Resumes a suspended task.

        When a non-repeating task is resumed and the task fire time has elapsed, it will run immediately. If the fire time did not elapse, it will run at the scheduled time.

        When a repeating task is resumed, it will not fire immediately, but at the next scheduled fire time based on the previous scheduled fire time. If a custom UserCalendar is used, the UserCalendar will be called continually until a date greater or equal to the current time is generated.

        For example: A task is to run every hour using the SIMPLE calendar. The task's next fire time is 2:05, but was suspended at 1:30. If the task was resumed a week later at 5:30, the task would run at 6:05.

        Parameters:
        taskId - The Task ID of the task to be suspended.
        Returns:
        the current TaskStatus of the task.
        Throws:
        SchedulerNotAvailableException - Transaction is rolled-back or marked to roll-back. Thrown when there was a problem accessing the persistent store.
        TaskInvalid - No transaction rollback occurs. The task id is invalid or has been purged.
        TaskPending - No transaction rollback occurs. Thrown when another thread is currently modifying this row.
        IllegalTaskState - No transaction rollback occurs. The task has been cancelled or completed. Only suspended tasks can be resumed.
        NotificationException - No transaction rollback occurs. Thrown when the NotificationSink fails to fire due to an exception.
        Since:
        5.0
        See Also:
        TaskStatus.getTaskId()

      • findTasksByName

        java.util.Iterator findTasksByName(java.lang.String name)
                                   throws SchedulerNotAvailableException
        Finds all TaskInfo records with a specified name that were created by the caller's application.

        The name can include SQL wildcards (depending on the database platform). Common wildcards include:

        • '%' - Match all characters
        • '?' - Match one character.
        For example: a name such as "AR_??_Sales" would return names like:
        "AR_01_Sales" and "AR_ZZ_Sales", but not "AR_AAA_Sales"

        A name such as "AR_%" would return all names that begin with "AR_".

        Parameters:
        name - the name of the task to be found.
        Returns:
        An iterator that can be used to retrieve the TaskInfo for the found tasks.
        Throws:
        SchedulerNotAvailableException - No transaction rollback occurs. Thrown when there was a problem accessing the persistent store.
        Since:
        5.0

      • findTaskStatusByName

        java.util.Iterator findTaskStatusByName(java.lang.String name)
                                        throws SchedulerNotAvailableException
        Finds all TaskStatus records which have the specified name and were created by the caller's application.

        See the findTasksByName(java.lang.String name) method for a more detailed description of the name parameter.

        Parameters:
        name - the name of the task to be found.
        Returns:
        An iterator that can be used to retrieve the TaskStatus for the found tasks. These TaskStatus records are the same as those returned by the Scheduler.getStatus method.
        Throws:
        SchedulerNotAvailableException - No transaction rollback occurs. Thrown when there was a problem accessing the persistent store.
        Since:
        5.0

      • findTasksByName

        TaskInfo[] findTasksByName(java.lang.String name,
                         int beginIndex,
                         int endIndex)
                           throws SchedulerNotAvailableException

        Returns the subset of TaskInfo records between beginIndex and endIndex (0-based) that match the specified name and were created by the caller's application.

        The name can include SQL wildcards (depending on the database platform). Common wildcards include:
        • '%' - Match all characters
        • '?' - Match one character.
        For example: a name such as "AR_??_Sales" would return names like:
        "AR_01_Sales" and "AR_ZZ_Sales", but not "AR_AAA_Sales"

        A name such as "AR_%" would return all names that begin with "AR_".

        Parameters:
        name - the name of the task to be found.
        beginIndex - the beginning index of the tasks to retrieve (0 is the first element)
        endIndex - the end index of the tasks to retrieve. If endIndex is greater than the total number of tasks, then the endIndex is ignored.
        Returns:
        An array of TaskInfo records
        Throws:
        SchedulerNotAvailableException - No transaction rollback occurs. Thrown when there was a problem accessing the persistent store.
        java.lang.IndexOutOfBoundsException - Thrown when the beginIndex or endIndex is negative or when the beginIndex is larger than the endIndex.
        Since:
        6.0

      • findTaskStatusByName

        TaskStatus[] findTaskStatusByName(java.lang.String name,
                                int beginIndex,
                                int endIndex)
                                  throws SchedulerNotAvailableException

        Returns the subset of TaskStatus records between beginIndex and endIndex that match the specified name and were created by the caller's application.

        See the findTasksByName(java.lang.String name) method for a more detailed description of the name parameter.
        Parameters:
        name - the name of the task to be found.
        beginIndex - the beginning index of the tasks to retrieve (0 is the first element)
        endIndex - the end index of the tasks to retrieve. If endIndex is greater than the total number of tasks, then the endIndex is ignored.
        Returns:
        An array of TaskStatus records. These TaskStatus records are the same as those returned by the Scheduler.getStatus method.
        Throws:
        SchedulerNotAvailableException - No transaction rollback occurs. Thrown when there was a problem accessing the persistent store.
        Since:
        6.0
IBM WebSphere Application ServerTM
Release 9.0
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