Class ImportanceParameters

  extended byjavax.realtime.SchedulingParameters
      extended byjavax.realtime.PriorityParameters
          extended byjavax.realtime.ImportanceParameters

public class ImportanceParameters
extends PriorityParameters

Importance is an additional scheduling metric that may be used by some priority-based scheduling algorithms during overload conditions to differentiate execution order among threads of the same priority. In some real-time systems an external physical process determines the period of many threads. If rate-monotonic priority assignment is used to assign priorities many of the threads in the system may have the same priority because their periods are the same. However, it is conceivable that some threads may be more important than others and in an overload situation importance can help the scheduler decide which threads to execute first. The base scheduling algorithm represented by PriorityScheduler is not required to use importance. However, the RTSJ strongly suggests to implementers that a fairly simple subclass of PriorityScheduler that uses importance can offer value to some real-time applications.

Angelo Corsaro

Field Summary
protected  int importance
Fields inherited from class javax.realtime.PriorityParameters
Constructor Summary
ImportanceParameters(int priority, int importance)
          Create aninstance of ImportanceParameters.
Method Summary
 int getImportance()
          Gets the importance value.
 void setImportance(int importance)
          Sets the importance value.
 String toString()
Methods inherited from class javax.realtime.PriorityParameters
getPriority, setPriority
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail


protected int importance
Constructor Detail


public ImportanceParameters(int priority,
                            int importance)
                     throws IllegalArgumentException
Create aninstance of ImportanceParameters.

priority - The priority assigned to a thread. This value is used in place of the value returned by java.lang.Thread.setPriority(int)
importance - The importance value assigned to a thread.
IllegalArgumentException - Thrown if the given priority value is less than the minimum priority of the scheduler of any of the associated threads or greater then the maximum priority of the scheduler of any of the associated threads.
Method Detail


public int getImportance()
Gets the importance value.

the importance value.


public void setImportance(int importance)
Sets the importance value.

importance - the new importance value.


public String toString()
toString in class PriorityParameters

jRate is developed and maintained by the jRate project development team.
Copyright (c) 2001-2005 Angelo Corsaro and Morgan Deters.