javax.realtime
Class ImportanceParameters

java.lang.Object
  |
  +--javax.realtime.SchedulingParameters
        |
        +--javax.realtime.PriorityParameters
              |
              +--javax.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 differenciate 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.

Field Summary

private int

importance

Fields inherited from class javax.realtime.PriorityParameters

Constructor Summary

ImportanceParameters(int priority, int importance)
Create an instance of ImportanceParameters.

Method Summary

int	getImportance() Gets the importance value.
void	setImportance(int importance) Sets the importance.
java.lang.String	toString() Print the value of the importance value of the associated instance of Schedulable.

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

importance

private int importance

Constructor Detail

ImportanceParameters

public ImportanceParameters(int priority,
                            int importance)

Create an instance of ImportanceParameters.

Parameters:

priority - The priority assigned to an instance of Schedulable. This value is used in place of java.lang.Thread.priority.

importance - The importance value assigned to an instance of Schedulable.

Method Detail

getImportance

public int getImportance()

Gets the importance value.

Returns:

The value of importance for the associated instance of Schedulable.

setImportance

public void setImportance(int importance)

Sets the importance.

toString

public java.lang.String toString()

Print the value of the importance value of the associated instance of Schedulable.

Overrides:

toString in class PriorityParameters

Returns:

The string representing the value of priority.