Package lejos.robotics.objectdetection

Class FusorDetector

java.lang.Object

lejos.robotics.objectdetection.FusorDetector

All Implemented Interfaces:

FeatureDetector, FeatureListener

public class FusorDetector
extends java.lang.Object
implements FeatureDetector, FeatureListener

If you have a robot with multiple sensors (touch and range) and would like them to report to one listener, or if you want to control them at the same time (such as disabling them all at once) you can use this class.

This class maintains its own thread for checking the FeatureDetectors.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private class	FusorDetector.NotifyThread Thread to periodically notify listeners.

Field Summary

Fields

Modifier and Type	Field and Description
private int	delay The delay (in ms) between notifying listeners of detected features (if any are detected).
private java.util.ArrayList<FeatureDetector>	detectors
private boolean	enabled
private java.util.ArrayList<FeatureListener>	listeners
private java.util.ArrayList<RangeReadings>	readings

Constructor Summary

Constructors

Constructor and Description
FusorDetector()

Method Summary

Modifier and Type	Method and Description
void	addDetector(FeatureDetector detector) This method adds another FeatureDetector to the FusorDetector.
void	addListener(FeatureListener listener) Adds a listener to the FeatureDetector.
void	enableDetection(boolean on) This method enables/disables automatic scanning and listener reporting for this object and all FeatureDetectors used in this FusorDetector object.
void	featureDetected(Feature feature, FeatureDetector detector) This method must deal with different delays from different sensors.
int	getDelay() The minimum delay between notification of readings from the feature detector.
boolean	isEnabled() Indicates if automatic scanning mode and listener notification is currently enabled.
private void	notifyListeners(Feature feature)
Feature	scan() This method scans all the sensors added to this object and returns the amalgamated results.
void	setDelay(int delay) Sets the minimum delay between readings from the feature detector.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

detectors

private java.util.ArrayList<FeatureDetector> detectors

readings

private java.util.ArrayList<RangeReadings> readings

delay

private int delay

The delay (in ms) between notifying listeners of detected features (if any are detected).

enabled

private boolean enabled

listeners

private java.util.ArrayList<FeatureListener> listeners

Constructor Detail

FusorDetector

public FusorDetector()

Method Detail

addDetector

public void addDetector(FeatureDetector detector)

This method adds another FeatureDetector to the FusorDetector. This method will set the delay for this class to the largest delay if comes across from all the FeatureDetector objects added to it.

Parameters:

detector -

scan

public Feature scan()

This method scans all the sensors added to this object and returns the amalgamated results. NOTE: This method is not called by the thread code.

Specified by:

scan in interface FeatureDetector

Returns:

A feature it has detected. null if nothing found.

featureDetected

public void featureDetected(Feature feature,
                            FeatureDetector detector)

This method must deal with different delays from different sensors. e.g. Touch is 50 ms, while ultrasonic is 250 ms. But must amalgamate readings that are captured over same period. SOLUTION: Use listeners. Get max scan time (e.g. 250 ms) and wait that long for each listener to report in before reporting all at once.

Specified by:

featureDetected in interface FeatureListener

Parameters:

feature - The RangeReading, which contains angle and range.

notifyListeners

private void notifyListeners(Feature feature)

addListener

public void addListener(FeatureListener listener)

Description copied from interface: FeatureDetector

Adds a listener to the FeatureDetector. The FeatureListener will be notified when objects are detected.

Specified by:

addListener in interface FeatureDetector

Parameters:

listener - The FeatureListener that is notified every time a feature is detected.

enableDetection

public void enableDetection(boolean on)

This method enables/disables automatic scanning and listener reporting for this object and all FeatureDetectors used in this FusorDetector object.

Specified by:

enableDetection in interface FeatureDetector

Parameters:

on - true enables detection and notifications, false disables this class until it is enabled again.

getDelay

public int getDelay()

Description copied from interface: FeatureDetector

The minimum delay between notification of readings from the feature detector. If no objects are detected, no notification will occur. Some sensors, such as touch sensors, check the sensor more frequently than other sensors, such as range sensors.

Specified by:

getDelay in interface FeatureDetector

Returns:

The delay between sensor readings.

isEnabled

public boolean isEnabled()

Description copied from interface: FeatureDetector

Indicates if automatic scanning mode and listener notification is currently enabled. (true by default)

Specified by:

isEnabled in interface FeatureDetector

Returns:

true if enabled, false if not

setDelay

public void setDelay(int delay)

Description copied from interface: FeatureDetector

Sets the minimum delay between readings from the feature detector. The notification thread will notify FeatureListener objects every delay milliseconds, unless it takes longer to retrieve readings from the sensor.

Specified by:

setDelay in interface FeatureDetector

Parameters:

delay - The FeatureDetector will return one new set of readings every delay milliseconds.