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 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 mthreads 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 implementors that a fairly simple subclass of PriorityScheduler that uses importance can offer some value to some real-time applictions.

Field Summary

protected int

importance The importance

Fields inherited from class javax.realtime.PriorityParameters

priority

Constructor Summary

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

Method Summary

int	getImportance()
void	setImportance(int importance) Set the importance
java.lang.String	toString() Print the value of the priority and importance values 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

protected int importance

The importance

Constructor Detail

ImportanceParameters

public ImportanceParameters(int priority,
                            int importance)

Create an instance of .

Parameters:

priority - the priority assigned to a thread. This value is used in place of java.lang.Thread priority.

importance - the importance value assigned to a thread.

Method Detail

getImportance

public int getImportance()

Returns:

the importance

setImportance

public void setImportance(int importance)

Set the importance

Parameters:

importance - the new importance value

toString

public java.lang.String toString()

Print the value of the priority and importance values of the associated instance of Schedulable

Overrides:

toString in class PriorityParameters

Returns:

A string representing the value of priority.