Package jdk.dio.power

Interfaces and classes for power management of devices.

See: Description

Interface Summary

Interface	Description
PowerManaged	The PowerManaged interface provides methods that a Device class may implement to control how the underlying device hardware resource is managed by the power management facility of the device.
PowerManaged.Group	The Group interface provides methods for registering for power state changes of devices belonging to the same power management group.
PowerSavingHandler	The PowerSavingHandler interface defines methods for getting notified of power state change requests on a specific Device instance.

Package jdk.dio.power Description

Interfaces and classes for power management of devices.

A Device implementing class may implement the PowerManaged interface if the underlying device supports some form of power management and saving states that can be mapped to the states defined by this API.

The following sample code gives an examples of using the power saving/management API:

 class SignalLevelMonitor implements MonitoringListener, PowerSavingHandler {

     private ADCChannel channel = null;
     private boolean inRange = false;

     public void start(int channelID, int low, int high) throws IOException, UnavailableDeviceException,
             DeviceNotFoundException {
         channel = (ADCChannel) DeviceManager.open(channelID);
         channel.setSamplingInterval(1000); // every 1 seconds
         channel.startMonitoring(low, high, this);
         if (channel instanceof PowerManaged) {
             ((PowerManaged) channel).enablePowerSaving(PowerManaged.LOW_POWER, this); // Only enable LOW_POWER saving mode (POWER_ON is implicit)
         }
     }

     @Override
     public void thresholdReached(MonitoringEvent event) {
         inRange = (event.getType() == MonitoringEvent.BACK_TO_RANGE);
     }

     @Override
     public <P extends Device<? super P>> long handlePowerStateChangeRequest(P device,
             PowerManaged.Group group, int currentState, int requestedState, long duration) {
         if (requestedState == PowerManaged.LOW_POWER) {
             return inRange ? duration : 0; // Only accept to change to LOW_POWER if signal is back in range
         }
         return duration; // Accept returning to POWER_ON
     }

     @Override
     public <P extends Device<? super P>> void handlePowerStateChange(P device,
             PowerManaged.Group group, int currentState, int requestedState, long duration) {
         // Do nothing
     }

     public void stop() throws IOException {
         if (channel != null) {
             channel.stopMonitoring();
             if (channel instanceof PowerManaged) {
                 ((PowerManaged) channel).disablePowerSaving();
             }
             channel.close();
         }
     }
 }
 

Unless otherwise noted, passing a null argument to a constructor or method in any class or interface in this package will cause a NullPointerException to be thrown.