Navigator

java.lang.Object
- lejos.robotics.navigation.Navigator

All Implemented Interfaces:

WaypointListener
```
public class Navigator
extends java.lang.Object
implements WaypointListener
```
This class controls a robot to traverse a Path, a sequence of Waypoints. It's default mode for a new path is continuous movement (no stopping at waypoints) but see also singleStep(boolean). To interrupt the path traversal, call stop(). It uses an inner class running its own thread to issue movement commands to its MoveController, which can be either a DifferentialPilot or lejos.robotics.navigation.SteeringPilot. It also uses a PoseProvider Calls its NavigationListeners when a Waypoint is reached or the robot stops. This class has only one blocking method: waitForStop() .

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

private class Navigator.Nav
This inner class runs the thread that processes the waypoint queue

Nested Classes
Modifier and Type	Class and Description
`private class`	`Navigator.Nav` This inner class runs the thread that processes the waypoint queue

Field Summary

Fields
Modifier and Type	Field and Description
`private Waypoint`	`_destination`
`private boolean`	`_interrupted` set by Stop, reset by followPath() , goTo() used by Nav.run(), callListeners
`private boolean`	`_keepGoing` frequently tested by Nav.run() to break out of primary control loop reset by stop(), and in Nav if _singleStep is set.
`private java.util.ArrayList<NavigationListener>`	`_listeners`
`private Navigator.Nav`	`_nav`
`private Path`	`_path`
`private MoveController`	`_pilot`
`private Pose`	`_pose`
`private double`	`_radius`
`private int`	`_sequenceNr`
`private boolean`	`_singleStep` if true, causes Nav.run to break whenever waypoint is reached.
`private PoseProvider`	`poseProvider`

Constructor Summary

Constructors
Constructor and Description
`Navigator(MoveController pilot)` Allocates a Navigator object, using pilot that implements the ArcMoveController interface.
`Navigator(MoveController pilot, PoseProvider poseProvider)` Allocates a Navigator object using a pilot and a custom poseProvider, rather than the default OdometryPoseProvider.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addNavigationListener(NavigationListener listener)` Adds a NavigationListener that is informed when a the robot stops or reaches a WayPoint.
`void`	`addWaypoint(float x, float y)` Constructs an new Waypoint from the parameters and adds it to the end of the path.
`void`	`addWaypoint(float x, float y, float heading)` Constructs an new Waypoint from the parameters and adds it to the end of the path.
`void`	`addWaypoint(Waypoint aWaypoint)` Adds a Waypoint to the end of the path.
`private void`	`callListeners()`
`void`	`clearPath()` Clears the current path.
`void`	`followPath()` Starts the robot traversing the current path.
`void`	`followPath(Path path)` Starts the robot traversing the path.
`MoveController`	`getMoveController()` Returns the MoveController belonging to this object.
`Path`	`getPath()` Gets the current path
`PoseProvider`	`getPoseProvider()` Returns the PoseProvider
`Waypoint`	`getWaypoint()` Returns the waypoint to which the robot is presently moving.
`void`	`goTo(float x, float y)` Starts the moving toward the destination Waypoint created from the parameters.
`void`	`goTo(float x, float y, float heading)` Starts the moving toward the destination Waypoint created from the parameters.
`void`	`goTo(Waypoint destination)` Starts the robot moving toward the destination.
`boolean`	`isMoving()` Returns `true if the robot is moving toward a waypoint.`
`boolean`	`pathCompleted()` Returns `true` if the the final waypoint has been reached
`void`	`pathGenerated()` Called when generation of the path is complete
`boolean`	`rotateTo(double angle)` Rotates the robot to a new absolute heading.
`void`	`setPath(Path path)` Sets the path that the Navigator will traverse.
`void`	`setPoseProvider(PoseProvider aProvider)` Sets the PoseProvider after construction of the Navigator
`void`	`singleStep(boolean yes)` Controls whether the robot stops at each Waypoint; applies to the current path only.
`void`	`stop()` Stops the robot.
`boolean`	`waitForStop()` Waits for the robot to stop for any reason ; returns `true` if the robot stopped at the final Waypoint of the path.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - _nav
```
private Navigator.Nav _nav
```
  - _path
```
private Path _path
```
  - _keepGoing
```
private boolean _keepGoing
```
    frequently tested by Nav.run() to break out of primary control loop reset by stop(), and in Nav if _singleStep is set. or end of path is reached set by followPath(xx) and goTo(xx)
  - _singleStep
```
private boolean _singleStep
```
    if true, causes Nav.run to break whenever waypoint is reached.
  - _interrupted
```
private boolean _interrupted
```
    set by Stop, reset by followPath() , goTo() used by Nav.run(), callListeners
  - _pilot
```
private MoveController _pilot
```
  - poseProvider
```
private PoseProvider poseProvider
```
  - _pose
```
private Pose _pose
```
  - _destination
```
private Waypoint _destination
```
  - _radius
```
private double _radius
```
  - _sequenceNr
```
private int _sequenceNr
```
  - _listeners
```
private java.util.ArrayList<NavigationListener> _listeners
```
- Constructor Detail
  - Navigator
```
public Navigator(MoveController pilot)
```
    Allocates a Navigator object, using pilot that implements the ArcMoveController interface.
    
    Parameters:
    
    pilot -
  - Navigator
```
public Navigator(MoveController pilot,
                 PoseProvider poseProvider)
```
    Allocates a Navigator object using a pilot and a custom poseProvider, rather than the default OdometryPoseProvider.
    
    Parameters:
    
    pilot - the pilot
    
    poseProvider - the custom PoseProvider
- Method Detail
  - setPoseProvider
```
public void setPoseProvider(PoseProvider aProvider)
```
    Sets the PoseProvider after construction of the Navigator
    
    Parameters:
    
    aProvider - the PoseProvider
  - addNavigationListener
```
public void addNavigationListener(NavigationListener listener)
```
    Adds a NavigationListener that is informed when a the robot stops or reaches a WayPoint.
    
    Parameters:
    
    listener - the NavitationListener
  - getPoseProvider
```
public PoseProvider getPoseProvider()
```
    Returns the PoseProvider
    
    Returns:
    
    the PoseProvider
  - getMoveController
```
public MoveController getMoveController()
```
    Returns the MoveController belonging to this object.
    
    Returns:
    
    the pilot
  - setPath
```
public void setPath(Path path)
```
    Sets the path that the Navigator will traverse. By default, the robot will not stop along the way. If the robot is moving when this method is called, it stops and the current path is replaced by the new one.
    
    Parameters:
    
    path - to be followed.
  - clearPath
```
public void clearPath()
```
    Clears the current path. If the robot is moving when this method is called, it stops;
  - getPath
```
public Path getPath()
```
    Gets the current path
    
    Returns:
    
    the path
  - followPath
```
public void followPath(Path path)
```
    Starts the robot traversing the path. This method is non-blocking.
    
    Parameters:
    
    path - to be followed.
  - followPath
```
public void followPath()
```
    Starts the robot traversing the current path. This method is non-blocking;
  - singleStep
```
public void singleStep(boolean yes)
```
    Controls whether the robot stops at each Waypoint; applies to the current path only. The robot will move to the next Waypoint if you call followPath().
    
    Parameters:
    
    yes - if true , the robot stops at each Waypoint.
  - goTo
```
public void goTo(Waypoint destination)
```
    Starts the robot moving toward the destination. If no path exists, a new one is created consisting of the destination, otherwise the destination is added to the path. This method is non-blocking, and is equivalent to addWaypoint(destination); followPath();
    
    Parameters:
    
    destination - the waypoint to be reached
  - goTo
```
public void goTo(float x,
                 float y)
```
    Starts the moving toward the destination Waypoint created from the parameters. If no path exists, a new one is created, otherwise the new Waypoint is added to the path. This method is non-blocking, and is equivalent to add(float x, float y); followPath();
    
    Parameters:
    
    x - coordinate of the destination
    
    y - coordinate of the destination
  - goTo
```
public void goTo(float x,
                 float y,
                 float heading)
```
    Starts the moving toward the destination Waypoint created from the parameters. If no path exists, a new one is created, otherwise the new Waypoint is added to the path. This method is non-blocking, and is equivalent to add(float x, float y); followPath();
    
    Parameters:
    
    x - coordinate of the destination
    
    y - coordinate of th destination
    
    heading - desired robot heading at arrival
  - rotateTo
```
public boolean rotateTo(double angle)
```
    Rotates the robot to a new absolute heading. For example, rotateTo(0) will line the robot with the x-axis, while rotateTo(90) lines it with the y-axis. If the robot is currently on the move to a coordinate, this method will not attempt to rotate and it will return false.
    
    Parameters:
    
    angle - The absolute heading to rotate the robot to. Value is 0 to 360.
    
    Returns:
    
    true if the rotation happened, false if the robot was moving while this method was called.
  - addWaypoint
```
public void addWaypoint(Waypoint aWaypoint)
```
    Adds a Waypoint to the end of the path. Call followPath() to start moving the along the current path.
    
    Specified by:
    
    addWaypoint in interface WaypointListener
    
    Parameters:
    
    aWaypoint - to be added
  - addWaypoint
```
public void addWaypoint(float x,
                        float y)
```
    Constructs an new Waypoint from the parameters and adds it to the end of the path. Call followPath() to start moving the along the current path.
    
    Parameters:
    
    x - coordinate of the waypoint
    
    y - coordinate of the waypoint
  - addWaypoint
```
public void addWaypoint(float x,
                        float y,
                        float heading)
```
    Constructs an new Waypoint from the parameters and adds it to the end of the path. Call followPath() to start moving the along the current path.
    
    Parameters:
    
    x - coordinate of the waypoint
    
    y - coordinate of the waypoint
    
    heading - the heading of the robot when it reaches the waypoint
  - stop
```
public void stop()
```
    Stops the robot. The robot will resume its path traversal if you call followPath().
  - getWaypoint
```
public Waypoint getWaypoint()
```
    Returns the waypoint to which the robot is presently moving.
    
    Returns:
    
    the waypoint ; null if the path is empty.
  - pathCompleted
```
public boolean pathCompleted()
```
    Returns true if the the final waypoint has been reached
    
    Returns:
    
    true if the path is completed
  - waitForStop
```
public boolean waitForStop()
```
    Waits for the robot to stop for any reason ; returns true if the robot stopped at the final Waypoint of the path.
    
    Returns:
    
    true if the path is completed
  - isMoving
```
public boolean isMoving()
```
    Returns true if the robot is moving toward a waypoint.
    Returns: true if moving.
  pathGenerated public void pathGenerated() Description copied from interface: WaypointListener Called when generation of the path is complete Specified by: pathGenerated in interface WaypointListener callListeners private void callListeners()

Class Navigator

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

_nav

_path

_keepGoing

_singleStep

_interrupted

_pilot

poseProvider

_pose

_destination

_radius

_sequenceNr

_listeners

Constructor Detail

Navigator

Navigator

Method Detail

setPoseProvider

addNavigationListener

getPoseProvider

getMoveController

setPath

clearPath

getPath

followPath

followPath

singleStep

goTo

goTo

goTo

rotateTo

addWaypoint

addWaypoint

addWaypoint

stop

getWaypoint

pathCompleted

waitForStop

isMoving

pathGenerated

callListeners