com.jspell.domain
Class RandomAccessFile

java.lang.Object
  extended by com.jspell.domain.RandomAccessFile
All Implemented Interfaces:
java.io.DataInput, java.io.DataOutput

public class RandomAccessFile
extends java.lang.Object
implements java.io.DataInput, java.io.DataOutput

A buffered java.io.RandomAccessFile. Increased default buffer size. Buffer minimum of file size or buffer size.

Version:
$Id: RandomAccessFile.java,v 1.2 2006/01/18 13:09:30 clifford_admin Exp $
Author:
Clifford Helsel
See Also:
DataInput, DataOutput, RandomAccessFile

Field Summary
protected  byte[] buffer
          The buffer used to load the data.
protected  long bufferStart
          The offset in bytes of the start of the buffer, from the start of the file.
static int CREATE
          Create the file rather than overwriting it.
protected  long dataEnd
          The offset in bytes of the end of the data in the buffer, from the start of the file.
protected  int dataSize
          The size of the data stored in the buffer, in bytes.
protected static int defaultBufferSize
          The default buffer size, in bytes.
protected  boolean endOfFile
          True if we are at the end of the file.
protected  java.io.RandomAccessFile file
          The underlying java.io.RandomAccessFile.
protected  long filePosition
          The offset in bytes from the file start, of the next read or write operation.
protected  int mode
          The access mode of the file.
static int READ
          Read from the file.
static int WRITE
          Write to the file.
 
Constructor Summary
  RandomAccessFile(java.io.File file, java.lang.String modeString)
          Creates a random access file stream to read from, and optionally to write to, the file specified by the File argument.
protected RandomAccessFile(int bufferSize)
          An implementation of a buffered RandomAccessFile.
  RandomAccessFile(java.lang.String filename, int mode)
          Create a new buffered random-access file with a default buffer size.
  RandomAccessFile(java.lang.String filename, int mode, int bufferSize)
          Create a new buffered random-access file with a specified buffer size.
  RandomAccessFile(java.lang.String filename, java.lang.String modeString)
          Creates a random access file stream to read from, and optionally to write to, a file with the specified name.
  RandomAccessFile(java.lang.String filename, java.lang.String modeString, int bufferSize)
          Creates a random access file stream to read from, and optionally to write to, a file with the specified name.
 
Method Summary
static void benchmark(java.lang.String filename, int bufferSize)
          Benchmark the performance of the new RandomAccessFile class.
 void close()
          Close the file, and release any associated system resources.
 void flush()
          Copy the contents of the buffer to the disk.
 java.io.FileDescriptor getFD()
          Returns the opaque file descriptor object associated with this file.
 long getFilePointer()
          Returns the current position in the file, where the next read or write will occur.
 long length()
          Get the length of the file.
static void main(java.lang.String[] argv)
          Test the RandomAccessFile class.
protected  int read_(long pos, byte[] b, int offset, int len)
          Undocumented.
 int read()
          Read a byte of data from the file, blocking until data is available.
 int read(byte[] b)
          Read up to b.length( ) bytes into an array.
 int read(byte[] b, int off, int len)
          Read up to len bytes into an array, at a specified offset.
 boolean readBoolean()
          Reads a boolean from this file.
 byte readByte()
          Reads a signed 8-bit value from this file.
 char readChar()
          Reads a Unicode character from this file.
 double readDouble()
          Reads a double from this file.
 float readFloat()
          Reads a float from this file.
 void readFully(byte[] b)
          Reads b.length bytes from this file into the byte array.
 void readFully(byte[] b, int off, int len)
          Reads exactly len bytes from this file into the byte array.
 int readInt()
          Reads a signed 32-bit integer from this file.
 java.lang.String readLine()
          Reads the next line of text from this file.
 long readLong()
          Reads a signed 64-bit integer from this file.
 short readShort()
          Reads a signed 16-bit number from this file.
 int readUnsignedByte()
          Reads an unsigned 8-bit number from this file.
 int readUnsignedShort()
          Reads an unsigned 16-bit number from this file.
 java.lang.String readUTF()
          Reads in a string from this file.
 java.lang.String readUTF(java.io.DataInput in)
           
 void seek(long pos)
          Set the position in the file for the next read or write.
 int skipBytes(int n)
          Skips exactly n bytes of input.
static void testBlocks(java.lang.String filename)
          Test the block operations of the RandomAccessFile class.
static void testBytes(java.lang.String filename, int bufferSize)
          Test the byte operations of the RandomAccessFile class.
 java.lang.String toString()
          Create a string representation of this object.
 void unread()
          Unread the last byte read.
 void write(byte[] b)
          Writes b.length bytes from the specified byte array starting at offset off to this file.
 void write(byte[] b, int off, int len)
          Writes len bytes from the specified byte array starting at offset off to this file.
 void write(int b)
          Write a byte to the file.
 void writeBoolean(boolean v)
          Writes a boolean to the file as a 1-byte value.
 void writeByte(int v)
          Writes a byte to the file as a 1-byte value.
 void writeBytes(byte[] b, int off, int len)
          Write len bytes from an array to the file.
 void writeBytes(char[] b, int off, int len)
          Writes the character array to the file as a sequence of bytes.
 void writeBytes(java.lang.String s)
          Writes the string to the file as a sequence of bytes.
 void writeChar(int v)
          Writes a char to the file as a 2-byte value, high byte first.
 void writeChars(char[] c)
          Writes a char[] to the file as a sequence of characters.
 void writeChars(java.lang.String s)
          Writes a string to the file as a sequence of characters.
 void writeDouble(double v)
          Converts the double argument to a long using the doubleToLongBits method in class Double, and then writes that long value to the file as an 8-byte quantity, high byte first.
 void writeFloat(float v)
          Converts the float argument to an int using the floatToIntBits method in class Float, and then writes that int value to the file as a 4-byte quantity, high byte first.
 void writeInt(int v)
          Writes an int to the file as four bytes, high byte first.
 void writeLong(long v)
          Writes a long to the file as eight bytes, high byte first.
 void writeShort(int v)
          Writes a short to the file as two bytes, high byte first.
 void writeUTF(java.lang.String str)
          Writes a string to the file using UTF-8 encoding in a machine-independent manner.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

READ

public static final int READ
Read from the file. This is always implied.

See Also:
Constant Field Values

WRITE

public static final int WRITE
Write to the file.

See Also:
Constant Field Values

CREATE

public static final int CREATE
Create the file rather than overwriting it. This is ignored if mode is not also WRITE.

See Also:
Constant Field Values

defaultBufferSize

protected static final int defaultBufferSize
The default buffer size, in bytes.

See Also:
Constant Field Values

file

protected java.io.RandomAccessFile file
The underlying java.io.RandomAccessFile.


filePosition

protected long filePosition
The offset in bytes from the file start, of the next read or write operation.


buffer

protected byte[] buffer
The buffer used to load the data.


bufferStart

protected long bufferStart
The offset in bytes of the start of the buffer, from the start of the file.


dataEnd

protected long dataEnd
The offset in bytes of the end of the data in the buffer, from the start of the file. This can be calculated from bufferStart + dataSize, but it is cached to speed up the read( ) method.


dataSize

protected int dataSize
The size of the data stored in the buffer, in bytes. This may be less than the size of the buffer.


endOfFile

protected boolean endOfFile
True if we are at the end of the file.


mode

protected int mode
The access mode of the file. This is a logical OR of READ, WRITE and CREATE.

Constructor Detail

RandomAccessFile

protected RandomAccessFile(int bufferSize)
An implementation of a buffered RandomAccessFile.

Parameters:
bufferSize - The size of the buffer.

RandomAccessFile

public RandomAccessFile(java.lang.String filename,
                        int mode)
                 throws java.io.IOException
Create a new buffered random-access file with a default buffer size. Note that the mode CREATE implies WRITE.

Parameters:
filename - the name of the file.
mode - how the file is to be opened. This may be a combination (logical OR) of CREATE, WRITE, and READ.
Throws:
java.io.IOException - if an I/O error occurrs.

RandomAccessFile

public RandomAccessFile(java.lang.String filename,
                        java.lang.String modeString)
                 throws java.io.IOException
Creates a random access file stream to read from, and optionally to write to, a file with the specified name.

The mode argument must either be equal to "r" or "rw", indicating that the file is to be opened for input only or for both input and output, respectively. If the mode is "rw" and the file does not exist, then an attempt is made to create it.

Parameters:
filename - A String for the file name.
modeString - A String for the mode in which to open the file.
Throws:
java.io.IOException - if an I/O error occurs.
See Also:
SecurityException, SecurityManager.checkRead(java.lang.String)

RandomAccessFile

public RandomAccessFile(java.lang.String filename,
                        java.lang.String modeString,
                        int bufferSize)
                 throws java.io.IOException
Creates a random access file stream to read from, and optionally to write to, a file with the specified name.

The mode argument must either be equal to "r" or "rw", indicating that the file is to be opened for input only or for both input and output, respectively. If the mode is "rw" and the file does not exist, then an attempt is made to create it.

Parameters:
filename - A String containing the file name.
modeString - A string containing the mode in which to open the file.
bufferSize - The size of the buffer.
Throws:
java.io.IOException - if an I/O error occurs.
See Also:
SecurityException, SecurityManager.checkRead(java.lang.String)

RandomAccessFile

public RandomAccessFile(java.io.File file,
                        java.lang.String modeString)
                 throws java.io.IOException
Creates a random access file stream to read from, and optionally to write to, the file specified by the File argument. A new FileDescriptor object is created to represent this file connection.

The mode argument must either be equal to "r" or "rw", indicating that the file is to be opened for input only or for both input and output, respectively. The write methods on this object will always throw an IOException if the file is opened with a mode of "r". If the mode is "rw" and the file does not exist, then an attempt is made to create it.

Parameters:
modeString - A string containing the mode in which to open the file.
file - the file object.
Throws:
java.io.IOException - if an I/O error occurs.
See Also:
File.getPath(), SecurityManager.checkRead(java.lang.String)

RandomAccessFile

public RandomAccessFile(java.lang.String filename,
                        int mode,
                        int bufferSize)
                 throws java.io.FileNotFoundException,
                        java.io.IOException
Create a new buffered random-access file with a specified buffer size. Note that the mode CREATE implies WRITE, and the READ is always implied.

Parameters:
filename - the name of the file.
mode - how the file is to be opened. This may be a combination (logical OR) of CREATE, WRITE, and READ.
bufferSize - the size of the temporary buffer, in bytes.
Throws:
java.io.FileNotFoundException - if the access is readonly and the file doesn't exist.
java.io.IOException - if an I/O error occurrs.
Method Detail

close

public void close()
           throws java.io.IOException
Close the file, and release any associated system resources.

Throws:
java.io.IOException - if an I/O error occurrs.

seek

public void seek(long pos)
          throws java.io.IOException
Set the position in the file for the next read or write.

Parameters:
pos - the offset (in bytes) from the start of the file.
Throws:
java.io.IOException - if an I/O error occurrs.

getFilePointer

public long getFilePointer()
                    throws java.io.IOException
Returns the current position in the file, where the next read or write will occur.

Returns:
the offset from the start of the file in bytes.
Throws:
java.io.IOException - if an I/O error occurrs.

length

public long length()
            throws java.io.IOException
Get the length of the file. The data in the buffer (which may not have been written the disk yet) is taken into account.

Returns:
the length of the file in bytes.
Throws:
java.io.IOException - if an I/O error occurrs.

getFD

public java.io.FileDescriptor getFD()
                             throws java.io.IOException
Returns the opaque file descriptor object associated with this file.

Returns:
the file descriptor object associated with this file.
Throws:
java.io.IOException - if an I/O error occurs.

flush

public void flush()
           throws java.io.IOException
Copy the contents of the buffer to the disk.

Throws:
java.io.IOException - if an I/O error occurrs.

read

public final int read()
               throws java.io.IOException
Read a byte of data from the file, blocking until data is available.

Returns:
the next byte of data, or -1 if the end of the file is reached.
Throws:
java.io.IOException - if an I/O error occurrs.

read_

protected int read_(long pos,
                    byte[] b,
                    int offset,
                    int len)
             throws java.io.IOException
Undocumented.

Parameters:
pos - Undocumented.
b - Undocumented.
offset - Undocumented.
len - Undocumented.
Returns:
Undocumented.
Throws:
java.io.IOException - Undocumented.

read

public int read(byte[] b,
                int off,
                int len)
         throws java.io.IOException
Read up to len bytes into an array, at a specified offset. This will block until at least one byte has been read.

Parameters:
b - the byte array to receive the bytes.
off - the offset in the array where copying will start.
len - the number of bytes to copy.
Returns:
the actual number of bytes read, or -1 if there is not more data due to the end of the file being reached.
Throws:
java.io.IOException - if an I/O error occurrs.

read

public int read(byte[] b)
         throws java.io.IOException
Read up to b.length( ) bytes into an array. This will block until at least one byte has been read.

Parameters:
b - the byte array to receive the bytes.
Returns:
the actual number of bytes read, or -1 if there is not more data due to the end of the file being reached.
Throws:
java.io.IOException - if an I/O error occurrs.

readFully

public final void readFully(byte[] b)
                     throws java.io.IOException
Reads b.length bytes from this file into the byte array. This method reads repeatedly from the file until all the bytes are read. This method blocks until all the bytes are read, the end of the stream is detected, or an exception is thrown.

Specified by:
readFully in interface java.io.DataInput
Parameters:
b - the buffer into which the data is read.
Throws:
java.io.IOException - if an I/O error occurs.

readFully

public final void readFully(byte[] b,
                            int off,
                            int len)
                     throws java.io.IOException
Reads exactly len bytes from this file into the byte array. This method reads repeatedly from the file until all the bytes are read. This method blocks until all the bytes are read, the end of the stream is detected, or an exception is thrown.

Specified by:
readFully in interface java.io.DataInput
Parameters:
b - the buffer into which the data is read.
off - the start offset of the data.
len - the number of bytes to read.
Throws:
java.io.IOException - if an I/O error occurs.

skipBytes

public int skipBytes(int n)
              throws java.io.IOException
Skips exactly n bytes of input. This method blocks until all the bytes are skipped, the end of the stream is detected, or an exception is thrown.

Specified by:
skipBytes in interface java.io.DataInput
Parameters:
n - the number of bytes to be skipped.
Returns:
the number of bytes skipped, which is always n.
Throws:
java.io.IOException - if an I/O error occurs.

unread

public final void unread()
Unread the last byte read. This method should not be used more than once between reading operations, or strange things might happen.


write

public final void write(int b)
                 throws java.io.IOException
Write a byte to the file. If the file has not been opened for writing, an IOException will be raised only when an attempt is made to write the buffer to the file.

Caveat: the effects of seek( )ing beyond the end of the file are undefined.

Specified by:
write in interface java.io.DataOutput
Parameters:
b - The byte to write.
Throws:
java.io.IOException - if an I/O error occurrs.

writeBytes

public final void writeBytes(byte[] b,
                             int off,
                             int len)
                      throws java.io.IOException
Write len bytes from an array to the file.

Parameters:
b - the array containing the data.
off - the offset in the array to the data.
len - the length of the data.
Throws:
java.io.IOException - if an I/O error occurrs.

write

public void write(byte[] b)
           throws java.io.IOException
Writes b.length bytes from the specified byte array starting at offset off to this file.

Specified by:
write in interface java.io.DataOutput
Parameters:
b - the data.
Throws:
java.io.IOException - if an I/O error occurs.

write

public void write(byte[] b,
                  int off,
                  int len)
           throws java.io.IOException
Writes len bytes from the specified byte array starting at offset off to this file.

Specified by:
write in interface java.io.DataOutput
Parameters:
b - the data.
off - the start offset in the data.
len - the number of bytes to write.
Throws:
java.io.IOException - if an I/O error occurs.

readBoolean

public final boolean readBoolean()
                          throws java.io.IOException
Reads a boolean from this file. This method reads a single byte from the file. A value of 0 represents false. Any other value represents true. This method blocks until the byte is read, the end of the stream is detected, or an exception is thrown.

Specified by:
readBoolean in interface java.io.DataInput
Returns:
the boolean value read.
Throws:
java.io.IOException - if an I/O error occurs.

readByte

public final byte readByte()
                    throws java.io.IOException
Reads a signed 8-bit value from this file. This method reads a byte from the file. If the byte read is b, where 0 <= b <= 255, then the result is:

This method blocks until the byte is read, the end of the stream is detected, or an exception is thrown.

Specified by:
readByte in interface java.io.DataInput
Returns:
the next byte of this file as a signed 8-bit byte.
Throws:
java.io.IOException - if an I/O error occurs.

readUnsignedByte

public final int readUnsignedByte()
                           throws java.io.IOException
Reads an unsigned 8-bit number from this file. This method reads a byte from this file and returns that byte.

This method blocks until the byte is read, the end of the stream is detected, or an exception is thrown.

Specified by:
readUnsignedByte in interface java.io.DataInput
Returns:
the next byte of this file, interpreted as an unsigned 8-bit number.
Throws:
java.io.IOException - if an I/O error occurs.

readShort

public final short readShort()
                      throws java.io.IOException
Reads a signed 16-bit number from this file. The method reads 2 bytes from this file. If the two bytes read, in order, are b1 and b2, where each of the two values is between 0 and 255, inclusive, then the result is equal to:

This method blocks until the two bytes are read, the end of the stream is detected, or an exception is thrown.

Specified by:
readShort in interface java.io.DataInput
Returns:
the next two bytes of this file, interpreted as a signed 16-bit number.
Throws:
java.io.IOException - if an I/O error occurs.

readUnsignedShort

public final int readUnsignedShort()
                            throws java.io.IOException
Reads an unsigned 16-bit number from this file. This method reads two bytes from the file. If the bytes read, in order, are b1 and b2, where 0 <= b1, b2 <= 255, then the result is equal to:

This method blocks until the two bytes are read, the end of the stream is detected, or an exception is thrown.

Specified by:
readUnsignedShort in interface java.io.DataInput
Returns:
the next two bytes of this file, interpreted as an unsigned 16-bit integer.
Throws:
java.io.IOException - if an I/O error occurs.

readChar

public final char readChar()
                    throws java.io.IOException
Reads a Unicode character from this file. This method reads two bytes from the file. If the bytes read, in order, are b1 and b2, where 0 <= b1, b2 <= 255, then the result is equal to:

This method blocks until the two bytes are read, the end of the stream is detected, or an exception is thrown.

Specified by:
readChar in interface java.io.DataInput
Returns:
the next two bytes of this file as a Unicode character.
Throws:
java.io.IOException - if an I/O error occurs.

readInt

public final int readInt()
                  throws java.io.IOException
Reads a signed 32-bit integer from this file. This method reads 4 bytes from the file. If the bytes read, in order, are b1, b2, b3, and b4, where 0 <= b1, b2, b3, b4 <= 255, then the result is equal to:

This method blocks until the four bytes are read, the end of the stream is detected, or an exception is thrown.

Specified by:
readInt in interface java.io.DataInput
Returns:
the next four bytes of this file, interpreted as an int.
Throws:
java.io.IOException - if an I/O error occurs.

readLong

public final long readLong()
                    throws java.io.IOException
Reads a signed 64-bit integer from this file. This method reads eight bytes from the file. If the bytes read, in order, are b1, b2, b3, b4, b5, b6, b7, and b8, where:

then the result is equal to:

 ((long) b1 << 56) + ((long) b2 << 48) + ((long) b3 << 40) + ((long) b4 << 32)
                + ((long) b5 << 24) + ((long) b6 << 16) + ((long) b7 << 8) + b8
 

This method blocks until the eight bytes are read, the end of the stream is detected, or an exception is thrown.

Specified by:
readLong in interface java.io.DataInput
Returns:
the next eight bytes of this file, interpreted as a long.
Throws:
java.io.IOException - if an I/O error occurs.

readFloat

public final float readFloat()
                      throws java.io.IOException
Reads a float from this file. This method reads an int value as if by the readInt method and then converts that int to a float using the intBitsToFloat method in class Float.

This method blocks until the four bytes are read, the end of the stream is detected, or an exception is thrown.

Specified by:
readFloat in interface java.io.DataInput
Returns:
the next four bytes of this file, interpreted as a float.
Throws:
java.io.IOException - if an I/O error occurs.
See Also:
RandomAccessFile.readInt(), Float.intBitsToFloat(int)

readDouble

public final double readDouble()
                        throws java.io.IOException
Reads a double from this file. This method reads a long value as if by the readLong method and then converts that long to a double using the longBitsToDouble method in class Double.

This method blocks until the eight bytes are read, the end of the stream is detected, or an exception is thrown.

Specified by:
readDouble in interface java.io.DataInput
Returns:
the next eight bytes of this file, interpreted as a double.
Throws:
java.io.IOException - if an I/O error occurs.
See Also:
RandomAccessFile.readLong(), Double.longBitsToDouble(long)

readLine

public final java.lang.String readLine()
                                throws java.io.IOException
Reads the next line of text from this file. This method successively reads bytes from the file until it reaches the end of a line of text.

A line of text is terminated by a carriage-return character ('\r'), a newline character ('\n'), a carriage-return character immediately followed by a newline character, or the end of the input stream. The line-terminating character(s), if any, are included as part of the string returned.

This method blocks until a newline character is read, a carriage return and the byte following it are read (to see if it is a newline), the end of the stream is detected, or an exception is thrown.

Specified by:
readLine in interface java.io.DataInput
Returns:
the next line of text from this file.
Throws:
java.io.IOException - if an I/O error occurs.

readUTF

public final java.lang.String readUTF()
                               throws java.io.IOException
Reads in a string from this file. The string has been encoded using a modified UTF-8 format.

The first two bytes are read as if by readUnsignedShort. This value gives the number of following bytes that are in the encoded string, not the length of the resulting string. The following bytes are then interpreted as bytes encoding characters in the UTF-8 format and are converted into characters.

This method blocks until all the bytes are read, the end of the stream is detected, or an exception is thrown.

Specified by:
readUTF in interface java.io.DataInput
Returns:
a Unicode string.
Throws:
java.io.IOException - if an I/O error occurs.
See Also:
RandomAccessFile.readUnsignedShort()

readUTF

public final java.lang.String readUTF(java.io.DataInput in)
                               throws java.io.IOException
Throws:
java.io.IOException

writeBoolean

public final void writeBoolean(boolean v)
                        throws java.io.IOException
Writes a boolean to the file as a 1-byte value. The value true is written out as the value (byte)1; the value false is written out as the value (byte)0.

Specified by:
writeBoolean in interface java.io.DataOutput
Parameters:
v - a boolean value to be written.
Throws:
java.io.IOException - if an I/O error occurs.

writeByte

public final void writeByte(int v)
                     throws java.io.IOException
Writes a byte to the file as a 1-byte value.

Specified by:
writeByte in interface java.io.DataOutput
Parameters:
v - a byte value to be written.
Throws:
java.io.IOException - if an I/O error occurs.

writeShort

public final void writeShort(int v)
                      throws java.io.IOException
Writes a short to the file as two bytes, high byte first.

Specified by:
writeShort in interface java.io.DataOutput
Parameters:
v - a short to be written.
Throws:
java.io.IOException - if an I/O error occurs.

writeChar

public final void writeChar(int v)
                     throws java.io.IOException
Writes a char to the file as a 2-byte value, high byte first.

Specified by:
writeChar in interface java.io.DataOutput
Parameters:
v - a char value to be written.
Throws:
java.io.IOException - if an I/O error occurs.

writeInt

public final void writeInt(int v)
                    throws java.io.IOException
Writes an int to the file as four bytes, high byte first.

Specified by:
writeInt in interface java.io.DataOutput
Parameters:
v - an int to be written.
Throws:
java.io.IOException - if an I/O error occurs.

writeLong

public final void writeLong(long v)
                     throws java.io.IOException
Writes a long to the file as eight bytes, high byte first.

Specified by:
writeLong in interface java.io.DataOutput
Parameters:
v - a long to be written.
Throws:
java.io.IOException - if an I/O error occurs.

writeFloat

public final void writeFloat(float v)
                      throws java.io.IOException
Converts the float argument to an int using the floatToIntBits method in class Float, and then writes that int value to the file as a 4-byte quantity, high byte first.

Specified by:
writeFloat in interface java.io.DataOutput
Parameters:
v - a float value to be written.
Throws:
java.io.IOException - if an I/O error occurs.
See Also:
Float.floatToIntBits(float)

writeDouble

public final void writeDouble(double v)
                       throws java.io.IOException
Converts the double argument to a long using the doubleToLongBits method in class Double, and then writes that long value to the file as an 8-byte quantity, high byte first.

Specified by:
writeDouble in interface java.io.DataOutput
Parameters:
v - a double value to be written.
Throws:
java.io.IOException - if an I/O error occurs.
See Also:
Double.doubleToLongBits(double)

writeBytes

public final void writeBytes(java.lang.String s)
                      throws java.io.IOException
Writes the string to the file as a sequence of bytes. Each character in the string is written out, in sequence, by discarding its high eight bits.

Specified by:
writeBytes in interface java.io.DataOutput
Parameters:
s - a string of bytes to be written.
Throws:
java.io.IOException - if an I/O error occurs.

writeBytes

public final void writeBytes(char[] b,
                             int off,
                             int len)
                      throws java.io.IOException
Writes the character array to the file as a sequence of bytes. Each character in the string is written out, in sequence, by discarding its high eight bits.

Parameters:
b - a character array of bytes to be written.
off - the index of the first character to write.
len - the number of characters to write.
Throws:
java.io.IOException - if an I/O error occurs.

writeChars

public final void writeChars(java.lang.String s)
                      throws java.io.IOException
Writes a string to the file as a sequence of characters. Each character is written to the data output stream as if by the writeChar method.

Specified by:
writeChars in interface java.io.DataOutput
Parameters:
s - a String value to be written.
Throws:
java.io.IOException - if an I/O error occurs.
See Also:
RandomAccessFile.writeChar(int)

writeChars

public final void writeChars(char[] c)
                      throws java.io.IOException
Writes a char[] to the file as a sequence of characters. Each character is written to the data output stream as if by the writeChar method.

Parameters:
c - an array of char to be writen.
Throws:
java.io.IOException - if an I/O error occurs.
See Also:
RandomAccessFile.writeChar(int)

writeUTF

public final void writeUTF(java.lang.String str)
                    throws java.io.IOException
Writes a string to the file using UTF-8 encoding in a machine-independent manner.

First, two bytes are written to the file as if by the writeShort method giving the number of bytes to follow. This value is the number of bytes actually written out, not the length of the string. Following the length, each character of the string is output, in sequence, using the UTF-8 encoding for each character.

Specified by:
writeUTF in interface java.io.DataOutput
Parameters:
str - a string to be written.
Throws:
java.io.IOException - if an I/O error occurs.

toString

public java.lang.String toString()
Create a string representation of this object.

Overrides:
toString in class java.lang.Object
Returns:
a string representation of the state of the object.

testBytes

public static void testBytes(java.lang.String filename,
                             int bufferSize)
Test the byte operations of the RandomAccessFile class. These are the methods that read/write on a byte-by-byte basis. The following checks are made: The test file is 4.5 times the size of the buffer, in order to test paging between buffers, and using files that end in the middle of a buffer. A constant seed value is used for the random number generator, to ensure any bugs are reproduceable.

Parameters:
filename - the name of the test file to generate.
bufferSize - the size of the buffer to use.

testBlocks

public static void testBlocks(java.lang.String filename)
Test the block operations of the RandomAccessFile class. These are the methods that read/write blocks of data. The following checks are made:

Parameters:
filename - the name of the test file to generate.

benchmark

public static void benchmark(java.lang.String filename,
                             int bufferSize)
Benchmark the performance of the new RandomAccessFile class. Its speed is compared to that of a java.io.RandomAccessFile, based on reading and writing a test file, byte by byte.

Parameters:
filename - the name of the test file.
bufferSize - the buffer size to use.

main

public static void main(java.lang.String[] argv)
Test the RandomAccessFile class. This involves testing the byte methods, the block methods, and benchmarking the performance. By appending 'test' or 'benchmark' to the command-line, it can be limited to the tests or benchmarking alone. The test filename is only used for the benchmarking, the other tests create a file called "temp.data" in the current directory. Note that the size of the buffer determines the size of the test file (which is 4.5 times the size of the buffer).

Parameters:
argv - Usage: [bufferSize] [test | benchmark]
See Also:
testBytes(String filename, int bufferSize), testBlocks(String filename), benchmark(String filename, int bufferSize)


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