net.freeutils.scrollphat

Class JNADevDevice

java.lang.Object

net.freeutils.scrollphat.Device

net.freeutils.scrollphat.JNADevDevice

All Implemented Interfaces:

Closeable, AutoCloseable

public class JNADevDevice
extends Device

A device implementation that uses the /dev/i2c-* device interface for the I2C communications with the device, and JNA for ioctl calls.

This implementation requires the i2c-dev kernel module to be loaded, and the JNA library to be available on the classpath, including its native libjnidispatch.so library which can also be specified using the java.library.path system property or LD_LIBRARY_PATH environment variable. The implementation works with the current Sun/Oracle JVM on Linux, but may not work on other systems.

See Also:

Linux kernel I2C Documentation

Field Summary

Fields

Modifier and Type	Field and Description
protected byte[]	buf
protected FileOutputStream	out

Fields inherited from class net.freeutils.scrollphat.Device

ADDR_GND, ADDR_SCL, ADDR_SDA, ADDR_VCC, CONFIG_AUDIO_INPUT, CONFIG_DISPLAY_MATRIX_1, CONFIG_DISPLAY_MATRIX_1_AND_2, CONFIG_DISPLAY_MATRIX_2, CONFIG_MATRIX_5X11, CONFIG_MATRIX_6X10, CONFIG_MATRIX_7X9, CONFIG_MATRIX_8X8, CONFIG_SOFTWARE_SHUTDOWN, errors, height, REG_BRIGHTNESS_CONFIG, REG_BRIGHTNESS_PWM, REG_CONFIG, REG_MATRIX1_DATA_START, REG_MATRIX2_DATA_START, REG_RESET, REG_UPDATE, shutdownHook, throwErrorCount, warnErrorCount, width

Constructor Summary

Constructors

Constructor and Description
JNADevDevice()

Method Summary

Modifier and Type	Method and Description
protected void	closeImpl() Closes the I2C bus and device.
protected int	getNativeFileDescriptor(FileDescriptor fd) Returns the native file descriptor associated with the Java file descriptor.
protected void	ioctl(int fd, int request, int data) Invokes the native ioctl function.
protected Device	openImpl(int busNumber, int address) Opens the connection to the I2C bus and to the device at the given address.
protected void	writeImpl(byte register, byte[] data, int offset, int length) Writes a series of bytes of data starting at the given register.
protected void	writeImpl(byte register, int data) Writes a single byte of data to the given register.

Methods inherited from class net.freeutils.scrollphat.Device

close, closeOnShutdown, configure, displayTestPatterns, getHeight, getWidth, handleError, init, main, newInstance, newInstance, open, open, reset, setBrightness, setDisplay, setDisplay, setDisplay, setDisplay, update, update, write, write

Methods inherited from class java.lang.Object

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

Field Detail

out

protected FileOutputStream out

buf

protected byte[] buf

Constructor Detail

JNADevDevice

public JNADevDevice()

Method Detail

getNativeFileDescriptor

protected int getNativeFileDescriptor(FileDescriptor fd)
                               throws IOException

Returns the native file descriptor associated with the Java file descriptor.

Parameters:

fd - the Java file descriptor

Returns:

the native file descriptor associated with the Java file descriptor

Throws:

IOException - if an error occurs

ioctl

protected void ioctl(int fd,
                     int request,
                     int data)
              throws IOException

Invokes the native ioctl function.

Parameters:

fd - the file descriptor

request - the ioctl request type constant

data - the data for the request

Throws:

IOException - if an error occurs

openImpl

protected Device openImpl(int busNumber,
                          int address)
                   throws IOException

Description copied from class: Device

Opens the connection to the I2C bus and to the device at the given address.

Specified by:

openImpl in class Device

Parameters:

busNumber - the I2C bus number to use

address - the I2C device address

Returns:

this device

Throws:

IOException - if an error occurs

closeImpl

protected void closeImpl()
                  throws IOException

Description copied from class: Device

Closes the I2C bus and device.

This method may be called multiple times, or without a successful call to Device.open(int) before it.

Specified by:

closeImpl in class Device

Throws:

IOException - if an error occurs

writeImpl

protected void writeImpl(byte register,
                         int data)
                  throws IOException

Description copied from class: Device

Writes a single byte of data to the given register.

Overrides:

writeImpl in class Device

Parameters:

register - the register to write to

data - the data to write (only the lower 8 bits are written)

Throws:

IOException - if an error occurs

writeImpl

protected void writeImpl(byte register,
                         byte[] data,
                         int offset,
                         int length)
                  throws IOException

Description copied from class: Device

Writes a series of bytes of data starting at the given register. The register number is incremented by one after each written byte.

Specified by:

writeImpl in class Device

Parameters:

register - the register to write to

data - an array containing the data to write

offset - the offset within the array of the first byte to write

length - the number of bytes to write

Throws:

IOException - if an error occurs