jwo.landserf.process.io
Class FileIO

java.lang.Object
  jwo.landserf.process.io.FileIO

Direct Known Subclasses:

BinRasterIO, BinVectorIO, ImageIO, LandSerfIO, ShapefileIO, TextRasterIO, TextVectorIO, VrmlIO, XmlIO

public class FileIO

extends Object

Superclass of all file IO classes. Stores the last error that might have been generated if problem reading or writing a file. Also contains convenience methods for reading and writing binary integers, doubles and floating points from input streams and random access files. Keeps track of a file pointer and byte order.

Version:

2.2, 18th September, 2004.

Author:

Jo Wood

Field Summary

static int	BIG_ENDIAN Indicates 'big endian' or Motorola byte ordering.
protected static int	bitsPerValue Bits per value (likely to be 8, 16, 32, or 64)
protected static int	byteOrder Byte order for binary files.
protected static String	errorMessage Last error message or null if no errors.
protected static long	filePointer Keeps track of read position in binary file.
static int	GATHER_INFO Indicates file should be scanned for without loading data.
protected static int	lineNumber Keeps track of line number in text file.
static int	LITTLE_ENDIAN Indicates 'little endian' or Intel byte ordering.
static int	LOAD_ALL Indicates all data should be loaded when reading a file
static int	LOAD_SELECTED Indicates only selected data should be loaded when reading a file.
protected static float	nullCode Value used to indicate null or missing values.
protected static boolean	substituteNull Indicates whether or not to substitute nulls for selected values.
protected static boolean	useMultiplier Indicates whether or not to scale z values by the multiplier.
protected static float	zMultiplier Multiplier used for scaling z values.

Constructor Summary

FileIO()
There should be no need to call the constructor explicitly since all methods are static.

Method Summary

static String	getErrorMessage() Reports the last error message, or null if last file operation was sucessful.
protected static byte	readByte(InputStream is) Reads in a single byte from the given input stream.
protected static byte	readByte(RandomAccessFile raf) Reads a single byte of data from the given random access file.
protected static String	readCharacters(int numChars, BufferedInputStream inStream) Reads in a given number of characters from the input stream and returns a text string representing them.
protected static String	readCharacters(int numChars, BufferedReader inFile) Reads in a given number of characters and returns text string representing them.
protected static double	readDouble(InputStream is) Reads a 64 bit double precision number from the given input stream.
protected static double	readDouble(RandomAccessFile raf) Reads a 64 bit double precision number from the given random access file.
protected static double	readDoubleBigEndian(InputStream is) Reads a 64 bit big endian double precision number from the given input stream.
protected static double	readDoubleBigEndian(RandomAccessFile raf) Reads a 64 bit big endian double precision number from the given random access file.
protected static double	readDoubleLittleEndian(InputStream is) Reads in a little-endian 8-byte double from the given input stream.
protected static double	readDoubleLittleEndian(RandomAccessFile raf) Reads a 64 bit little endian double precision number from the given random access file.
protected static float	readFloat(InputStream is) Reads a 32 bit floating point number from the given input stream.
protected static float	readFloat(RandomAccessFile raf) Reads a 32 bit floating point number from the given random access file.
protected static float	readFloatBigEndian(InputStream is) Reads in a big-endian 4-byte float from the given input stream.
protected static float	readFloatBigEndian(RandomAccessFile raf) Reads a 32 bit big endian floating point number from the given random access file.
protected static float	readFloatLittleEndian(InputStream is) Reads in a little-endian 4-byte float from the given input stream.
protected static float	readFloatLittleEndian(RandomAccessFile raf) Reads a 32 bit little endian floating point number from the given random access file.
protected static int	readInt(InputStream is) Reads a 32 bit unsigned word of data from the given input stream.
protected static int	readInt(RandomAccessFile raf) Reads a 32 bit unsigned word of data from the given random access file.
protected static int	readIntBigEndian(InputStream is) Reads in a big-endian 4-byte integer from the given input stream.
protected static int	readIntBigEndian(RandomAccessFile raf) Reads a 32 bit unsigned big endian word of data from the given random access file.
protected static int	readIntLittleEndian(InputStream is) Reads in a little-endian 4-byte integer from the given input stream.
protected static int	readIntLittleEndian(RandomAccessFile raf) Reads a 32 bit unsigned little endian word of data from the given random access file.
protected static String	readNextWord(BufferedReader inFile) Reads in the next non-whitespace set of characters.
protected static short	readShort(InputStream is) Reads a 16 bit unsigned word of data from the given input stream.
protected static short	readShort(RandomAccessFile raf) Reads a 16 bit unsigned word of data from the given random access file.
protected static short	readShortBigEndian(InputStream is) Reads in a big-endian 2-byte short integer from the given input stream.
protected static short	readShortBigEndian(RandomAccessFile raf) Reads a 16 bit unsigned big endian word of data from the given random access file.
protected static short	readShortLittleEndian(InputStream is) Reads in a little-endian 2-byte short integer from the given input stream.
protected static short	readShortLittleEndian(RandomAccessFile raf) Reads a 16 bit unsigned little endian word of data from the given random access file.
static void	reset() Resets the error message and file pointer to null.
protected static void	seek(RandomAccessFile raf, long numBytes) Moves the file pointer to the given offset from the start.
protected static void	skip(InputStream is, long numBytes) Skips the given number of bytes in the input stream.
protected static void	skip(RandomAccessFile raf, int numBytes) Skips the given number of bytes in the given random access file.
protected static boolean	writeByte(byte value, OutputStream os) Writes an 8 bit byte of data to the given output stream.
protected static boolean	writeCharacters(String text, OutputStream os) Writes out the given text as ASCII characters to the given output stream.
protected static boolean	writeDouble(double value, OutputStream os) Writes a 64 bit double precision value to the given output stream.
protected static boolean	writeDoubleBigEndian(double value, OutputStream os) Writes a little-endian 8-byte double to the given output stream.
protected static boolean	writeDoubleLittleEndian(double value, OutputStream os) Writes a little-endian 8-byte double to the given output stream.
protected static boolean	writeFloat(float value, OutputStream os) Writes a 32 bit float point value to the given output stream.
protected static boolean	writeFloatBigEndian(float value, OutputStream os) Writes a little-endian 4-byte float to the given output stream.
protected static boolean	writeFloatLittleEndian(float value, OutputStream os) Writes a little-endian 4-byte float to the given output stream.
protected static boolean	writeInt(int value, OutputStream os) Writes a 32 bit unsigned word of data to the given output stream.
protected static boolean	writeIntBigEndian(int value, OutputStream os) Writes a 32 bit unsigned big-endian ('Motorola') word of data to the given output stream.
protected static boolean	writeIntLittleEndian(int value, OutputStream os) Writes a 32 bit unsigned little-endian ('Intel') word of data to the given output stream.
protected static boolean	writeLine(String text, BufferedWriter outFile) Writes out a given line of text on its own line to the given buffered writer.
protected static boolean	writeShort(short value, OutputStream os) Writes a 16 bit unsigned word of data to the given output stream.
protected static boolean	writeShortBigEndian(short value, OutputStream os) Writes a 16 bit unsigned big-endian ('Motorola') word of data to the given output stream.
protected static boolean	writeShortLittleEndian(short value, OutputStream os) Writes a 16 bit unsigned little-endian ('Intel') word of data to the given output stream.

Methods inherited from class java.lang.Object

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

Field Detail

errorMessage

protected static String errorMessage

Last error message or null if no errors.

filePointer

protected static long filePointer

Keeps track of read position in binary file.

lineNumber

protected static int lineNumber

Keeps track of line number in text file.

bitsPerValue

protected static int bitsPerValue

Bits per value (likely to be 8, 16, 32, or 64)

byteOrder

protected static int byteOrder

Byte order for binary files. Either BIG_ENDIAN or LITTLE_ENDIAN

nullCode

protected static float nullCode

Value used to indicate null or missing values.

substituteNull

protected static boolean substituteNull

Indicates whether or not to substitute nulls for selected values.

zMultiplier

protected static float zMultiplier

Multiplier used for scaling z values.

useMultiplier

protected static boolean useMultiplier

Indicates whether or not to scale z values by the multiplier.

LOAD_ALL

public static final int LOAD_ALL

Indicates all data should be loaded when reading a file

See Also:

Constant Field Values

LOAD_SELECTED

public static final int LOAD_SELECTED

Indicates only selected data should be loaded when reading a file.

See Also:

Constant Field Values

GATHER_INFO

public static final int GATHER_INFO

Indicates file should be scanned for without loading data.

See Also:

Constant Field Values

BIG_ENDIAN

public static final int BIG_ENDIAN

Indicates 'big endian' or Motorola byte ordering. The most significant byte comes first in a sequence of bytes.

See Also:

Constant Field Values

LITTLE_ENDIAN

public static final int LITTLE_ENDIAN

Indicates 'little endian' or Intel byte ordering. The least significant byte comes first in a sequence of bytes.

See Also:

Constant Field Values

Constructor Detail

FileIO

public FileIO()

There should be no need to call the constructor explicitly since all methods are static.

Method Detail

reset

public static void reset()

Resets the error message and file pointer to null.

getErrorMessage

public static String getErrorMessage()

Reports the last error message, or null if last file operation was sucessful.

Returns:

Last error message or null if last operation was sucessful.

skip

protected static void skip(InputStream is,
                           long numBytes)

Skips the given number of bytes in the input stream.

Parameters:

is - Input stream.

numBytes - Number of 8-bit bytes to skip.

skip

protected static void skip(RandomAccessFile raf,
                           int numBytes)

Skips the given number of bytes in the given random access file.

Parameters:

raf - Random access file to process.

numBytes - Number of 8-bit bytes to skip.

seek

protected static void seek(RandomAccessFile raf,
                           long numBytes)

Moves the file pointer to the given offset from the start.

Parameters:

raf - Random access file to process.

numBytes - Number of bytes from start to move file pointer.

readByte

protected static byte readByte(InputStream is)

Reads in a single byte from the given input stream.

Parameters:

is - Input stream.

Returns:

Value read from input stream.

readByte

protected static byte readByte(RandomAccessFile raf)

Reads a single byte of data from the given random access file.

Parameters:

raf - Random access file to process.

Returns:

Data read from random access file.

readShort

protected static short readShort(RandomAccessFile raf)

Reads a 16 bit unsigned word of data from the given random access file. Assumes a byte order determined by the 'byteOrder'

Parameters:

raf - Random access file to process.

Returns:

Data read from random access file.

readShort

protected static short readShort(InputStream is)

Reads a 16 bit unsigned word of data from the given input stream. Assumes a byte order determined by the 'byteOrder'

Parameters:

is - Input stream to process.

Returns:

Data read from input stream.

writeByte

protected static boolean writeByte(byte value,
                                   OutputStream os)

Writes an 8 bit byte of data to the given output stream.

Parameters:

value - Value to write to output stream.

os - Output stream to process.

Returns:

True if written successfully.

writeShort

protected static boolean writeShort(short value,
                                    OutputStream os)

Writes a 16 bit unsigned word of data to the given output stream. Assumes a byte order determined by the 'byteOrder'

Parameters:

value - Value to write to output stream.

os - Output stream to process.

Returns:

True if written successfully.

writeFloat

protected static boolean writeFloat(float value,
                                    OutputStream os)

Writes a 32 bit float point value to the given output stream. Assumes a byte order determined by the 'byteOrder'

Parameters:

value - Value to write to output stream.

os - Output stream to process.

Returns:

True if written successfully.

writeDouble

protected static boolean writeDouble(double value,
                                     OutputStream os)

Writes a 64 bit double precision value to the given output stream. Assumes a byte order determined by the 'byteOrder'

Parameters:

value - Value to write to output stream.

os - Output stream to process.

Returns:

True if written successfully.

readInt

protected static int readInt(RandomAccessFile raf)

Reads a 32 bit unsigned word of data from the given random access file. Assumes a byte order determined by the 'byteOrder'

Parameters:

raf - Random access file to process.

Returns:

Data read from random access file.

readInt

protected static int readInt(InputStream is)

Reads a 32 bit unsigned word of data from the given input stream. Assumes a byte order determined by the 'byteOrder'

Parameters:

is - Input stream to process.

Returns:

Data read from input stream.

writeInt

protected static boolean writeInt(int value,
                                  OutputStream os)

Writes a 32 bit unsigned word of data to the given output stream. Assumes a byte order determined by the 'byteOrder'

Parameters:

value - Value to write to output stream.

os - Output stream to process.

Returns:

True if written successfully.

readFloat

protected static float readFloat(RandomAccessFile raf)

Reads a 32 bit floating point number from the given random access file. Assumes a byte order determined by the 'byteOrder'

Parameters:

raf - Random access file to process.

Returns:

Data read from random access file.

readFloat

protected static float readFloat(InputStream is)

Reads a 32 bit floating point number from the given input stream. Assumes a byte order determined by the 'byteOrder'

Parameters:

is - Input stream to process.

Returns:

Data read from input stream.

readDouble

protected static double readDouble(RandomAccessFile raf)

Reads a 64 bit double precision number from the given random access file. Assumes a byte order determined by the 'byteOrder'

Parameters:

raf - Random access file to process.

Returns:

Data read from random access file.

readDouble

protected static double readDouble(InputStream is)

Reads a 64 bit double precision number from the given input stream. Assumes a byte order determined by the 'byteOrder'

Parameters:

is - Input stream to process.

Returns:

Data read from input stream.

readShortLittleEndian

protected static short readShortLittleEndian(RandomAccessFile raf)

Reads a 16 bit unsigned little endian word of data from the given random access file.

Parameters:

raf - Random access file to process.

Returns:

Data read from random access file.

readShortLittleEndian

protected static short readShortLittleEndian(InputStream is)

Reads in a little-endian 2-byte short integer from the given input stream.

Parameters:

is - Input stream.

Returns:

Value read from input stream.

writeShortLittleEndian

protected static boolean writeShortLittleEndian(short value,
                                                OutputStream os)

Writes a 16 bit unsigned little-endian ('Intel') word of data to the given output stream.

Parameters:

value - Value to write to output stream.

os - Output stream to process.

Returns:

True if written successfully.

readIntLittleEndian

protected static int readIntLittleEndian(RandomAccessFile raf)

Reads a 32 bit unsigned little endian word of data from the given random access file.

Parameters:

raf - Random access file to process.

Returns:

Data read from random access file.

readIntLittleEndian

protected static int readIntLittleEndian(InputStream is)

Reads in a little-endian 4-byte integer from the given input stream.

Parameters:

is - Input stream.

Returns:

Value read from input stream.

writeIntLittleEndian

protected static boolean writeIntLittleEndian(int value,
                                              OutputStream os)

Writes a 32 bit unsigned little-endian ('Intel') word of data to the given output stream.

Parameters:

value - Value to write to output stream.

os - Output stream to process.

Returns:

True if written successfully.

readFloatLittleEndian

protected static float readFloatLittleEndian(RandomAccessFile raf)

Reads a 32 bit little endian floating point number from the given random access file.

Parameters:

raf - Random access file to process.

Returns:

Data read from random access file.

readFloatLittleEndian

protected static float readFloatLittleEndian(InputStream is)

Reads in a little-endian 4-byte float from the given input stream.

Parameters:

is - Input stream.

Returns:

Value read from input stream.

writeFloatBigEndian

protected static boolean writeFloatBigEndian(float value,
                                             OutputStream os)

Writes a little-endian 4-byte float to the given output stream.

Parameters:

value - Value to write to output stream.

os - Output stream.

Returns:

True if written successfully.

writeFloatLittleEndian

protected static boolean writeFloatLittleEndian(float value,
                                                OutputStream os)

Writes a little-endian 4-byte float to the given output stream.

Parameters:

value - Value to write to output stream.

os - Output stream.

Returns:

True if written successfully.

writeDoubleBigEndian

protected static boolean writeDoubleBigEndian(double value,
                                              OutputStream os)

Writes a little-endian 8-byte double to the given output stream.

Parameters:

value - Value to write to output stream.

os - Output stream.

Returns:

True if written successfully.

writeDoubleLittleEndian

protected static boolean writeDoubleLittleEndian(double value,
                                                 OutputStream os)

Writes a little-endian 8-byte double to the given output stream.

Parameters:

value - Value to write to output stream.

os - Output stream.

Returns:

True if written successfully.

readDoubleLittleEndian

protected static double readDoubleLittleEndian(RandomAccessFile raf)

Reads a 64 bit little endian double precision number from the given random access file.

Parameters:

raf - Random access file to process.

Returns:

Data read from random access file.

readDoubleLittleEndian

protected static double readDoubleLittleEndian(InputStream is)

Reads in a little-endian 8-byte double from the given input stream.

Parameters:

is - Input stream.

Returns:

Value read from input stream.

readShortBigEndian

protected static short readShortBigEndian(RandomAccessFile raf)

Reads a 16 bit unsigned big endian word of data from the given random access file.

Parameters:

raf - Random access file to process.

Returns:

Data read from random access file.

readShortBigEndian

protected static short readShortBigEndian(InputStream is)

Reads in a big-endian 2-byte short integer from the given input stream.

Parameters:

is - Input stream.

Returns:

Value read from input stream.

writeShortBigEndian

protected static boolean writeShortBigEndian(short value,
                                             OutputStream os)

Writes a 16 bit unsigned big-endian ('Motorola') word of data to the given output stream.

Parameters:

value - Value to write to output stream.

os - Output stream to process.

Returns:

True if written successfully.

readIntBigEndian

protected static int readIntBigEndian(RandomAccessFile raf)

Reads a 32 bit unsigned big endian word of data from the given random access file.

Parameters:

raf - Random access file to process.

Returns:

Data read from random access file.

readIntBigEndian

protected static int readIntBigEndian(InputStream is)

Reads in a big-endian 4-byte integer from the given input stream.

Parameters:

is - Input stream.

Returns:

Value read from input stream.

writeIntBigEndian

protected static boolean writeIntBigEndian(int value,
                                           OutputStream os)

Writes a 32 bit unsigned big-endian ('Motorola') word of data to the given output stream.

Parameters:

value - Value to write to output stream.

os - Output stream to process.

Returns:

True if written successfully.

readFloatBigEndian

protected static float readFloatBigEndian(RandomAccessFile raf)

Reads a 32 bit big endian floating point number from the given random access file.

Parameters:

raf - Random access file to process.

Returns:

Data read from random access file.

readFloatBigEndian

protected static float readFloatBigEndian(InputStream is)

Reads in a big-endian 4-byte float from the given input stream.

Parameters:

is - Input stream.

Returns:

Value read from input stream.

readDoubleBigEndian

protected static double readDoubleBigEndian(RandomAccessFile raf)

Reads a 64 bit big endian double precision number from the given random access file.

Parameters:

raf - Random access file to process.

Returns:

Data read from random access file.

readDoubleBigEndian

protected static double readDoubleBigEndian(InputStream is)

Reads a 64 bit big endian double precision number from the given input stream.

Parameters:

is - Input stream.

Returns:

Value read from input stream.

writeLine

protected static boolean writeLine(String text,
                                   BufferedWriter outFile)

Writes out a given line of text on its own line to the given buffered writer.

Parameters:

text - Text to write.

outFile - Buffered file writer to receive the text.

Returns:

true if written successfully.

readCharacters

protected static String readCharacters(int numChars,
                                       BufferedReader inFile)

Reads in a given number of characters and returns text string representing them. If the end of file is reached before reading is finished, the returned string will be suitably truncated. Note this does not keep track of line numbers since this method does not require line feed or carrage return characters to work.

Parameters:

numChars - Number of characters to read.

inFile - File from which to read.

Returns:

Text read or null if problem reading from file.

readCharacters

protected static String readCharacters(int numChars,
                                       BufferedInputStream inStream)

Reads in a given number of characters from the input stream and returns a text string representing them. If the end of file is reached before reading is finished, the returned string will be suitably truncated. Note this does not keep track of line numbers since this method does not require line feed or carrage return characters to work.

Parameters:

numChars - Number of characters to read.

inStream - Input stream from which to read.

Returns:

Text read or null if problem reading from file.

writeCharacters

protected static boolean writeCharacters(String text,
                                         OutputStream os)

Writes out the given text as ASCII characters to the given output stream. This method should be used for writing text in binary files only.

Parameters:

text - Text to write.

os - Output stream to use.

Returns:

True if written successfully.

readNextWord

protected static String readNextWord(BufferedReader inFile)

Reads in the next non-whitespace set of characters. Effectively acts as a simple instance of a string tokenizer. For efficiency reasons, this method will move the file pointer to 1 character after the last character of the word. This should not be a problem for whitespace separated text, but could be a problem for fixed width reading. Note this does not keep track of line numbers since this method does not require line feed or carrage return characters to work.

Parameters:

inFile - File from which to read.

Returns:

Text read or null if problem reading from file.