com.openxc.interfaces.usb

Class UsbVehicleInterface

java.lang.Object

com.openxc.sources.BaseVehicleDataSource

com.openxc.sources.ContextualVehicleDataSource

com.openxc.sources.BytestreamDataSource

com.openxc.interfaces.usb.UsbVehicleInterface

All Implemented Interfaces:

DataPipeline.Operator, VehicleInterface, VehicleDataSink, VehicleDataSource, java.lang.Runnable

public class UsbVehicleInterface
extends BytestreamDataSource
implements VehicleInterface

A vehicle data source reading measurements from an OpenXC USB device. This class looks for a USB device and expects to read OpenXC-compatible, newline separated JSON messages in USB bulk transfer packets. The device used (if different from the default) can be specified by passing an custom URI to the constructor. The expected format of this URI is defined in UsbDeviceUtilities. According to Android's USB device usage requirements, this class requests permission for the USB device from the user before accessing it. This may cause a pop-up dialog that the user must dismiss before the data source will become active.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	ACTION_USB_DEVICE_ATTACHED
static java.lang.String	ACTION_USB_PERMISSION
static java.lang.String	BROADCAST_USB_DISCONNECTED

Fields inherited from class com.openxc.sources.BytestreamDataSource

mConnectionLock, mDataFormatValue, mDeviceChanged, RECONNECTION_ATTEMPT_WAIT_TIME_S, SLOW_RECONNECTION_ATTEMPT_WAIT_TIME_S

Constructor Summary

Constructors

Constructor and Description
UsbVehicleInterface(android.content.Context context)
UsbVehicleInterface(android.content.Context context, java.lang.String uriString)
UsbVehicleInterface(SourceCallback callback, android.content.Context context) Construct an instance of UsbVehicleInterface with a receiver callback and the default device URI.
UsbVehicleInterface(SourceCallback callback, android.content.Context context, java.net.URI deviceUri) Construct an instance of UsbVehicleInterface with a receiver callback and custom device URI.

Method Summary

Modifier and Type	Method and Description
protected void	connect() Initiate a connection to the vehicle interface.
static java.net.URI	createUri(java.lang.String uriString)
protected void	disconnect() Perform any cleanup necessary to disconnect from the interface.
protected java.lang.String	getTag() Return a string suitable as a tag for logging.
boolean	isConnected() Return true if the data source is actively connected to its target, be it a USB endpoint, a Bluetooth channel, a trace file, etc.
protected int	read(byte[] bytes) Read data from the source into the given array.
protected void	sendUSBDisconnectBroadcast()
boolean	setResource(java.lang.String otherUri) Change the resource used by the instance to connect to the interface, restarting any necessary services.
void	start()
void	stop() Unregister USB device intent broadcast receivers and stop waiting for a connection.
java.lang.String	toString()
protected boolean	write(byte[] bytes)

Methods inherited from class com.openxc.sources.BytestreamDataSource

connected, disconnected, isRunning, receive, run, setFastPolling, stopConnectionAttempts, waitForConnection

Methods inherited from class com.openxc.sources.ContextualVehicleDataSource

getContext

Methods inherited from class com.openxc.sources.BaseVehicleDataSource

getCallback, handleMessage, onPipelineActivated, onPipelineDeactivated, setCallback, waitForCallback

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.openxc.sources.VehicleDataSource

setCallback

Methods inherited from interface com.openxc.DataPipeline.Operator

onPipelineActivated, onPipelineDeactivated

Methods inherited from interface com.openxc.sinks.VehicleDataSink

receive

Field Detail

BROADCAST_USB_DISCONNECTED

public static final java.lang.String BROADCAST_USB_DISCONNECTED

See Also:

Constant Field Values

ACTION_USB_PERMISSION

public static final java.lang.String ACTION_USB_PERMISSION

See Also:

Constant Field Values

ACTION_USB_DEVICE_ATTACHED

public static final java.lang.String ACTION_USB_DEVICE_ATTACHED

See Also:

Constant Field Values

Constructor Detail

UsbVehicleInterface

public UsbVehicleInterface(SourceCallback callback,
                           android.content.Context context,
                           java.net.URI deviceUri)
                    throws DataSourceException

Construct an instance of UsbVehicleInterface with a receiver callback and custom device URI. If the device cannot be found at initialization, the object will block waiting for a signal to check again.

Parameters:

context - The Activity or Service context, used to get access to the Android UsbManager.

callback - An object implementing the SourceCallback that should receive data as it is received and parsed.

deviceUri - a USB device URI (see UsbDeviceUtilities for the format) to look for.

Throws:

DataSourceException - If the URI doesn't have the correct format

UsbVehicleInterface

public UsbVehicleInterface(SourceCallback callback,
                           android.content.Context context)
                    throws DataSourceException

Construct an instance of UsbVehicleInterface with a receiver callback and the default device URI. The default device URI is specified in UsbDeviceUtilities.

Parameters:

context - The Activity or Service context, used to get access to the Android UsbManager.

callback - An object implementing the SourceCallback that should receive data as it is received and parsed.

Throws:

DataSourceException - in exceptional circumstances, i.e. only if the default device URI is malformed.

UsbVehicleInterface

public UsbVehicleInterface(android.content.Context context)
                    throws DataSourceException

Throws:

DataSourceException

UsbVehicleInterface

public UsbVehicleInterface(android.content.Context context,
                           java.lang.String uriString)
                    throws DataSourceException

Throws:

DataSourceException

Method Detail

start

public void start()

Overrides:

start in class BytestreamDataSource

isConnected

public boolean isConnected()

Description copied from interface: VehicleDataSource

Return true if the data source is actively connected to its target, be it a USB endpoint, a Bluetooth channel, a trace file, etc. The source is capable of providing new vehicle data. Returns true if connected, false otherwise.

Specified by:

isConnected in interface VehicleInterface

Specified by:

isConnected in interface VehicleDataSource

Overrides:

isConnected in class BytestreamDataSource

stop

public void stop()

Unregister USB device intent broadcast receivers and stop waiting for a connection. This should be called before the object is given up to the garbage collector to avoid leaking a receiver in the Android framework.

Specified by:

stop in interface VehicleDataSink

Specified by:

stop in interface VehicleDataSource

Overrides:

stop in class BytestreamDataSource

setResource

public boolean setResource(java.lang.String otherUri)
                    throws DataSourceException

Description copied from interface: VehicleInterface

Change the resource used by the instance to connect to the interface, restarting any necessary services.

Specified by:

setResource in interface VehicleInterface

Parameters:

otherUri - The new resource to use for the interface.

Returns:

true if the resource was different and the interface was restarted.

Throws:

DataSourceException

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

read

protected int read(byte[] bytes)
            throws java.io.IOException

Description copied from class: BytestreamDataSource

Read data from the source into the given array. No more than bytes.length bytes will be read, and there is no guarantee that any bytes will be read at all.

Specified by:

read in class BytestreamDataSource

Parameters:

bytes - the destination array for bytes from the data source.

Returns:

the number of bytes that were actually copied into bytes.

Throws:

java.io.IOException - if the source is unexpectedly closed or returns an error.

getTag

protected java.lang.String getTag()

Description copied from class: BaseVehicleDataSource

Return a string suitable as a tag for logging.

Overrides:

getTag in class BaseVehicleDataSource

write

protected boolean write(byte[] bytes)

Specified by:

write in class BytestreamDataSource

connect

protected void connect()
                throws DataSourceException

Description copied from class: BytestreamDataSource

Initiate a connection to the vehicle interface.

Specified by:

connect in class BytestreamDataSource

Throws:

DataSourceException

disconnect

protected void disconnect()

Description copied from class: BytestreamDataSource

Perform any cleanup necessary to disconnect from the interface.

Specified by:

disconnect in class BytestreamDataSource

createUri

public static java.net.URI createUri(java.lang.String uriString)
                              throws DataSourceException

Throws:

DataSourceException

sendUSBDisconnectBroadcast

protected void sendUSBDisconnectBroadcast()