com.softwareag.tamino.db.api.common
Class TReschedulableTimer

java.lang.Object
  extended by com.softwareag.tamino.db.api.common.TReschedulableTimer

public class TReschedulableTimer
extends java.lang.Object

A facility to schedule and reschedule tasks for future execution in a background thread. Tasks may be scheduled for one-time execution, or for repeated execution at regular intervals.

This class uses the java.util.Timer and therefore it has the same conditions. Except that it allows to reschedule a task.

Version:
$Revision: 1.1 $
Author:
Stefan Liebig
See Also:
Timer

Constructor Summary
TReschedulableTimer()
          Creates a new timer.
TReschedulableTimer(boolean isDaemon)
          Creates a new timer whose associated thread may be specified to run as a daemon.
 
Method Summary
 void reschedule(TReschedulableTask task, java.util.Date time)
          Reschedules the specified task for execution at the specified time.
 void reschedule(TReschedulableTask task, java.util.Date time, long period)
          Reschedules the specified task for repeated fixed-delay execution, beginning after the specified delay.
 void reschedule(TReschedulableTask task, long delay)
          Reschedules the specified task for execution after the specified delay.
 void reschedule(TReschedulableTask task, long delay, long period)
          Reschedules the specified task for repeated fixed-delay execution, beginning after the specified delay.
 void schedule(TReschedulableTask task, java.util.Date time)
          Schedules the specified task for execution at the specified time.
 void schedule(TReschedulableTask task, java.util.Date firstTime, long period)
          Schedules the specified task for repeated fixed-delay execution, beginning at the specified time.
 void schedule(TReschedulableTask task, long delay)
          Schedules the specified task for execution after the specified delay.
 void schedule(TReschedulableTask task, long delay, long period)
          Schedules the specified task for repeated fixed-delay execution, beginning after the specified delay.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

TReschedulableTimer

public TReschedulableTimer()
Creates a new timer. The associated thread does not run as a daemon.


TReschedulableTimer

public TReschedulableTimer(boolean isDaemon)
Creates a new timer whose associated thread may be specified to run as a daemon. A deamon thread is called for if the timer will be used to schedule repeating "maintenance activities", which must be performed as long as the application is running, but should not prolong the lifetime of the application.

Parameters:
isDaemon - true if the associated thread should run as a daemon.
Method Detail

schedule

public void schedule(TReschedulableTask task,
                     long delay)
Schedules the specified task for execution after the specified delay.

Parameters:
task - task to be scheduled.
delay - delay in milliseconds before task is to be executed.
Throws:
java.lang.IllegalArgumentException - if delay is negative, or delay + System.currentTimeMillis() is negative.
java.lang.IllegalStateException - if task was already scheduled or cancelled, or timer was cancelled.

schedule

public void schedule(TReschedulableTask task,
                     long delay,
                     long period)
Schedules the specified task for repeated fixed-delay execution, beginning after the specified delay. Subsequent executions take place at approximately regular intervals separated by the specified period.

In fixed-delay execution, each execution is scheduled relative to the actual execution time of the previous execution. If an execution is delayed for any reason (such as garbage collection or other background activity), subsequent executions will be delayed as well. In the long run, the frequency of execution will generally be slightly lower than the reciprocal of the specified period (assuming the system clock underlying Object.wait(long) is accurate).

Fixed-delay execution is appropriate for recurring activities that require "smoothness." In other words, it is appropriate for activities where it is more important to keep the frequency accurate in the short run than in the long run. This includes most animation tasks, such as blinking a cursor at regular intervals. It also includes tasks wherein regular activity is performed in response to human input, such as automatically repeating a character as long as a key is held down.

Parameters:
task - task to be scheduled.
delay - delay in milliseconds before task is to be executed.
period - time in milliseconds between successive task executions.
Throws:
java.lang.IllegalArgumentException - if delay is negative, or delay + System.currentTimeMillis() is negative.
java.lang.IllegalStateException - if task was already scheduled or cancelled, timer was cancelled, or timer thread terminated.

schedule

public void schedule(TReschedulableTask task,
                     java.util.Date time)
Schedules the specified task for execution at the specified time. If the time is in the past, the task is scheduled for immediate execution.

Parameters:
task - task to be scheduled.
time - time at which task is to be executed.
Throws:
java.lang.IllegalArgumentException - if time.getTime() is negative.
java.lang.IllegalStateException - if task was already scheduled or cancelled, timer was cancelled, or timer thread terminated.

schedule

public void schedule(TReschedulableTask task,
                     java.util.Date firstTime,
                     long period)
Schedules the specified task for repeated fixed-delay execution, beginning at the specified time. Subsequent executions take place at approximately regular intervals, separated by the specified period.

In fixed-delay execution, each execution is scheduled relative to the actual execution time of the previous execution. If an execution is delayed for any reason (such as garbage collection or other background activity), subsequent executions will be delayed as well. In the long run, the frequency of execution will generally be slightly lower than the reciprocal of the specified period (assuming the system clock underlying Object.wait(long) is accurate).

Fixed-delay execution is appropriate for recurring activities that require "smoothness." In other words, it is appropriate for activities where it is more important to keep the frequency accurate in the short run than in the long run. This includes most animation tasks, such as blinking a cursor at regular intervals. It also includes tasks wherein regular activity is performed in response to human input, such as automatically repeating a character as long as a key is held down.

Parameters:
task - task to be scheduled.
firstTime - First time at which task is to be executed.
period - time in milliseconds between successive task executions.
Throws:
java.lang.IllegalArgumentException - if time.getTime() is negative.
java.lang.IllegalStateException - if task was already scheduled or cancelled, timer was cancelled, or timer thread terminated.

reschedule

public void reschedule(TReschedulableTask task,
                       long delay)
Reschedules the specified task for execution after the specified delay.

Parameters:
task - task to be scheduled.
delay - delay in milliseconds before task is to be executed.
Throws:
java.lang.IllegalArgumentException - if delay is negative, or delay + System.currentTimeMillis() is negative.
java.lang.IllegalStateException - timer was cancelled.

reschedule

public void reschedule(TReschedulableTask task,
                       long delay,
                       long period)
Reschedules the specified task for repeated fixed-delay execution, beginning after the specified delay. Subsequent executions take place at approximately regular intervals separated by the specified period.

In fixed-delay execution, each execution is scheduled relative to the actual execution time of the previous execution. If an execution is delayed for any reason (such as garbage collection or other background activity), subsequent executions will be delayed as well. In the long run, the frequency of execution will generally be slightly lower than the reciprocal of the specified period (assuming the system clock underlying Object.wait(long) is accurate).

Fixed-delay execution is appropriate for recurring activities that require "smoothness." In other words, it is appropriate for activities where it is more important to keep the frequency accurate in the short run than in the long run. This includes most animation tasks, such as blinking a cursor at regular intervals. It also includes tasks wherein regular activity is performed in response to human input, such as automatically repeating a character as long as a key is held down.

Parameters:
task - task to be scheduled.
delay - delay in milliseconds before task is to be executed.
period - time in milliseconds between successive task executions.
Throws:
java.lang.IllegalArgumentException - if delay is negative, or delay + System.currentTimeMillis() is negative.
java.lang.IllegalStateException - if timer was cancelled, or timer thread terminated.

reschedule

public void reschedule(TReschedulableTask task,
                       java.util.Date time)
Reschedules the specified task for execution at the specified time. If the time is in the past, the task is scheduled for immediate execution.

Parameters:
task - task to be scheduled.
time - time at which task is to be executed.
Throws:
java.lang.IllegalArgumentException - if time.getTime() is negative.
java.lang.IllegalStateException - if timer was cancelled, or timer thread terminated.

reschedule

public void reschedule(TReschedulableTask task,
                       java.util.Date time,
                       long period)
Reschedules the specified task for repeated fixed-delay execution, beginning after the specified delay. Subsequent executions take place at approximately regular intervals separated by the specified period.

In fixed-delay execution, each execution is scheduled relative to the actual execution time of the previous execution. If an execution is delayed for any reason (such as garbage collection or other background activity), subsequent executions will be delayed as well. In the long run, the frequency of execution will generally be slightly lower than the reciprocal of the specified period (assuming the system clock underlying Object.wait(long) is accurate).

Fixed-delay execution is appropriate for recurring activities that require "smoothness." In other words, it is appropriate for activities where it is more important to keep the frequency accurate in the short run than in the long run. This includes most animation tasks, such as blinking a cursor at regular intervals. It also includes tasks wherein regular activity is performed in response to human input, such as automatically repeating a character as long as a key is held down.

Parameters:
task - task to be scheduled.
delay - delay in milliseconds before task is to be executed.
period - time in milliseconds between successive task executions.
Throws:
java.lang.IllegalArgumentException - if delay is negative, or delay + System.currentTimeMillis() is negative.
java.lang.IllegalStateException - if timer was cancelled, or timer thread terminated.


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