RandomAccessFile (genetica-libraries 1.0.5 API)

java.lang.Object
- umcg.genetica.io.bin.RandomAccessFile

All Implemented Interfaces:

DataInput, DataOutput
```
public class RandomAccessFile
extends Object
implements DataInput, DataOutput
```
A buffered drop-in replacement for java.io.RandomAccessFile. Instances of this class realise substantial speed increases over java.io.RandomAccessFile through the use of buffering. This is a subclass of Object, as it was not possible to subclass java.io.RandomAccessFile because many of the methods are final. However, if it is necessary to use RandomAccessFile and java.io.RandomAccessFile interchangeably, both classes implement the DataInput and DataOutput interfaces.

Version:

$Id: RandomAccessFile.java,v 1.2 1998/10/20 18:38:03 russ Exp $

Author:

Alex McManus, Russ Rew

See Also:

DataInput, DataOutput, RandomAccessFile

Field Summary

Fields
Modifier and Type	Field and Description
`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 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

Constructors
Constructor and Description
`RandomAccessFile(File file, String modeString)` Creates a random access file stream to read from, and optionally to write to, the file specified by the `File` argument.
`RandomAccessFile(File file, String modeString, int bufferSize)` Create a new buffered random-access file with a specified buffer size.
`RandomAccessFile(String filename, int mode)` Create a new buffered random-access file with a default buffer size.
`RandomAccessFile(String filename, int mode, int bufferSize)` Create a new buffered random-access file with a specified buffer size.
`RandomAccessFile(String filename, String modeString)` Creates a random access file stream to read from, and optionally to write to, a file with the specified name.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static void`	`benchmark(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.
`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.
`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.
`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.
`String`	`readUTF()` Reads in a string from this file.
`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(String filename)` Test the block operations of the RandomAccessFile class.
`static void`	`testBytes(String filename, int bufferSize)` Test the byte operations of the RandomAccessFile class.
`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(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(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(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 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
```
public RandomAccessFile(String filename,
                        int mode)
                 throws 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:
    
    IOException - if an I/O error occurrs.
    
    SecurityException - if a security manager exists, its checkRead method is called with the name argument to see if the application is allowed read access to the file. If the mode argument is WRITE, its checkWrite method also is called with the name argument to see if the application is allowed write access to the file. Either of these may result in a security exception.
  - RandomAccessFile
```
public RandomAccessFile(String filename,
                        String modeString)
                 throws 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:
    
    name - the system-dependent filename.
    
    mode - the access mode.
    
    Throws:
    
    IllegalArgumentException - if the mode argument is not equal to "r" or to "rw".
    
    IOException - if an I/O error occurs.
    
    SecurityException - if a security manager exists, its checkRead method is called with the name argument to see if the application is allowed read access to the file. If the mode argument is equal to "rw", its checkWrite method also is called with the name argument to see if the application is allowed write access to the file. Either of these may result in a security exception.
    
    See Also:
    
    SecurityException, SecurityManager.checkRead(java.lang.String)
  - RandomAccessFile
```
public RandomAccessFile(File file,
                        String modeString)
                 throws 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:
    
    file - the file object.
    
    mode - the access mode.
    
    Throws:
    
    IllegalArgumentException - if the mode argument is not equal to "r" or to "rw".
    
    IOException - if an I/O error occurs.
    
    SecurityException - if a security manager exists, its checkRead method is called with the pathname of the File argument to see if the application is allowed read access to the file. If the mode argument is equal to "rw", its checkWrite method also is called with the pathname to see if the application is allowed write access to the file.
    
    See Also:
    
    File.getPath(), SecurityManager.checkRead(java.lang.String)
  - RandomAccessFile
```
public RandomAccessFile(File file,
                        String modeString,
                        int bufferSize)
                 throws 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:
    
    IOException - if an I/O error occurrs.
    
    SecurityException - if a security manager exists, its checkRead method is called with the name argument to see if the application is allowed read access to the file. If the mode argument is WRITE, its checkWrite method also is called with the name argument to see if the application is allowed write access to the file. Either of these may result in a security exception.
  - RandomAccessFile
```
public RandomAccessFile(String filename,
                        int mode,
                        int bufferSize)
                 throws 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:
    
    IOException - if an I/O error occurrs.
    
    SecurityException - if a security manager exists, its checkRead method is called with the name argument to see if the application is allowed read access to the file. If the mode argument is WRITE, its checkWrite method also is called with the name argument to see if the application is allowed write access to the file. Either of these may result in a security exception.
- Method Detail
  - close
```
public void close()
           throws IOException
```
    Close the file, and release any associated system resources.
    
    Throws:
    
    IOException - if an I/O error occurrs.
  - seek
```
public final void seek(long pos)
                throws 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:
    
    IOException - if an I/O error occurrs.
  - getFilePointer
```
public final long getFilePointer()
                          throws 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:
    
    IOException - if an I/O error occurrs.
  - length
```
public long length()
            throws 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:
    
    IOException - if an I/O error occurrs.
  - getFD
```
public final FileDescriptor getFD()
                           throws IOException
```
    Returns the opaque file descriptor object associated with this file.
    
    Returns:
    
    the file descriptor object associated with this file.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - flush
```
public void flush()
           throws IOException
```
    Copy the contents of the buffer to the disk.
    
    Throws:
    
    IOException - if an I/O error occurrs.
  - read
```
public final int read()
               throws 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:
    
    IOException - if an I/O error occurrs.
  - read
```
public int read(byte[] b,
                int off,
                int len)
         throws 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:
    
    IOException - if an I/O error occurrs.
  - read
```
public int read(byte[] b)
         throws 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:
    
    IOException - if an I/O error occurrs.
  - readFully
```
public final void readFully(byte[] b)
                     throws 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 DataInput
    
    Parameters:
    
    b - the buffer into which the data is read.
    
    Throws:
    
    EOFException - if this file reaches the end before reading all the bytes.
    
    IOException - if an I/O error occurs.
  - readFully
```
public final void readFully(byte[] b,
                            int off,
                            int len)
                     throws 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 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:
    
    EOFException - if this file reaches the end before reading all the bytes.
    
    IOException - if an I/O error occurs.
  - skipBytes
```
public int skipBytes(int n)
              throws 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 DataInput
    
    Parameters:
    
    n - the number of bytes to be skipped.
    
    Returns:
    
    the number of bytes skipped, which is always n.
    
    Throws:
    
    EOFException - if this file reaches the end before skipping all the bytes.
    
    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 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 DataOutput
    
    Throws:
    
    IOException - if an I/O error occurrs.
  - writeBytes
```
public final void writeBytes(byte[] b,
                             int off,
                             int len)
                      throws 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:
    
    IOException - if an I/O error occurrs.
  - write
```
public void write(byte[] b)
           throws IOException
```
    Writes b.length bytes from the specified byte array starting at offset off to this file.
    
    Specified by:
    
    write in interface DataOutput
    
    Parameters:
    
    b - the data.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - write
```
public void write(byte[] b,
                  int off,
                  int len)
           throws IOException
```
    Writes len bytes from the specified byte array starting at offset off to this file.
    
    Specified by:
    
    write in interface DataOutput
    
    Parameters:
    
    b - the data.
    
    off - the start offset in the data.
    
    len - the number of bytes to write.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - readBoolean
```
public final boolean readBoolean()
                          throws 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 DataInput
    
    Returns:
    
    the boolean value read.
    
    Throws:
    
    EOFException - if this file has reached the end.
    
    IOException - if an I/O error occurs.
  - readByte
```
public final byte readByte()
                    throws 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 DataInput
    
    Returns:
    
    the next byte of this file as a signed 8-bit byte.
    
    Throws:
    
    EOFException - if this file has reached the end.
    
    IOException - if an I/O error occurs.
  - readUnsignedByte
```
public final int readUnsignedByte()
                           throws 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 DataInput
    
    Returns:
    
    the next byte of this file, interpreted as an unsigned 8-bit number.
    
    Throws:
    
    EOFException - if this file has reached the end.
    
    IOException - if an I/O error occurs.
  - readShort
```
public final short readShort()
                      throws 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 DataInput
    
    Returns:
    
    the next two bytes of this file, interpreted as a signed 16-bit number.
    
    Throws:
    
    EOFException - if this file reaches the end before reading two bytes.
    
    IOException - if an I/O error occurs.
  - readUnsignedShort
```
public final int readUnsignedShort()
                            throws 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 DataInput
    
    Returns:
    
    the next two bytes of this file, interpreted as an unsigned 16-bit integer.
    
    Throws:
    
    EOFException - if this file reaches the end before reading two bytes.
    
    IOException - if an I/O error occurs.
  - readChar
```
public final char readChar()
                    throws 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 DataInput
    
    Returns:
    
    the next two bytes of this file as a Unicode character.
    
    Throws:
    
    EOFException - if this file reaches the end before reading two bytes.
    
    IOException - if an I/O error occurs.
  - readInt
```
public final int readInt()
                  throws 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 DataInput
    
    Returns:
    
    the next four bytes of this file, interpreted as an int.
    
    Throws:
    
    EOFException - if this file reaches the end before reading four bytes.
    
    IOException - if an I/O error occurs.
  - readLong
```
public final long readLong()
                    throws 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 DataInput
    
    Returns:
    
    the next eight bytes of this file, interpreted as a long.
    
    Throws:
    
    EOFException - if this file reaches the end before reading eight bytes.
    
    IOException - if an I/O error occurs.
  - readFloat
```
public final float readFloat()
                      throws 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 DataInput
    
    Returns:
    
    the next four bytes of this file, interpreted as a float.
    
    Throws:
    
    EOFException - if this file reaches the end before reading four bytes.
    
    IOException - if an I/O error occurs.
    
    See Also:
    
    RandomAccessFile.readInt(), Float.intBitsToFloat(int)
  - readDouble
```
public final double readDouble()
                        throws 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 DataInput
    
    Returns:
    
    the next eight bytes of this file, interpreted as a double.
    
    Throws:
    
    EOFException - if this file reaches the end before reading eight bytes.
    
    IOException - if an I/O error occurs.
    
    See Also:
    
    RandomAccessFile.readLong(), Double.longBitsToDouble(long)
  - readLine
```
public final String readLine()
                      throws 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 DataInput
    
    Returns:
    
    the next line of text from this file.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - readUTF
```
public final String readUTF()
                     throws 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 DataInput
    
    Returns:
    
    a Unicode string.
    
    Throws:
    
    EOFException - if this file reaches the end before reading all the bytes.
    
    IOException - if an I/O error occurs.
    
    UTFDataFormatException - if the bytes do not represent valid UTF-8 encoding of a Unicode string.
    
    See Also:
    
    RandomAccessFile.readUnsignedShort()
  - writeBoolean
```
public final void writeBoolean(boolean v)
                        throws 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 DataOutput
    
    Parameters:
    
    v - a boolean value to be written.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - writeByte
```
public final void writeByte(int v)
                     throws IOException
```
    Writes a byte to the file as a 1-byte value.
    
    Specified by:
    
    writeByte in interface DataOutput
    
    Parameters:
    
    v - a byte value to be written.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - writeShort
```
public final void writeShort(int v)
                      throws IOException
```
    Writes a short to the file as two bytes, high byte first.
    
    Specified by:
    
    writeShort in interface DataOutput
    
    Parameters:
    
    v - a short to be written.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - writeChar
```
public final void writeChar(int v)
                     throws IOException
```
    Writes a char to the file as a 2-byte value, high byte first.
    
    Specified by:
    
    writeChar in interface DataOutput
    
    Parameters:
    
    v - a char value to be written.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - writeInt
```
public final void writeInt(int v)
                    throws IOException
```
    Writes an int to the file as four bytes, high byte first.
    
    Specified by:
    
    writeInt in interface DataOutput
    
    Parameters:
    
    v - an int to be written.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - writeLong
```
public final void writeLong(long v)
                     throws IOException
```
    Writes a long to the file as eight bytes, high byte first.
    
    Specified by:
    
    writeLong in interface DataOutput
    
    Parameters:
    
    v - a long to be written.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - writeFloat
```
public final void writeFloat(float v)
                      throws 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 DataOutput
    
    Parameters:
    
    v - a float value to be written.
    
    Throws:
    
    IOException - if an I/O error occurs.
    
    See Also:
    
    Float.floatToIntBits(float)
  - writeDouble
```
public final void writeDouble(double v)
                       throws 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 DataOutput
    
    Parameters:
    
    v - a double value to be written.
    
    Throws:
    
    IOException - if an I/O error occurs.
    
    See Also:
    
    Double.doubleToLongBits(double)
  - writeBytes
```
public final void writeBytes(String s)
                      throws 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 DataOutput
    
    Parameters:
    
    s - a string of bytes to be written.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - writeBytes
```
public final void writeBytes(char[] b,
                             int off,
                             int len)
                      throws 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:
    
    IOException - if an I/O error occurs.
  - writeChars
```
public final void writeChars(String s)
                      throws 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 DataOutput
    
    Parameters:
    
    s - a String value to be written.
    
    Throws:
    
    IOException - if an I/O error occurs.
    
    See Also:
    
    RandomAccessFile.writeChar(int)
  - writeUTF
```
public final void writeUTF(String str)
                    throws 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 DataOutput
    
    Parameters:
    
    str - a string to be written.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - toString
```
public String toString()
```
    Create a string representation of this object.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    a string representation of the state of the object.
  - testBytes
```
public static void testBytes(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:
    - Writing random bytes to a file.
    - Checking the size of the file is correct.
    - Checking that EOF is correctly raised.
    - Reading the file back in and verifying its contents.
    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(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:
    - Writing blocks of data that are smaller than the buffer size.
    - Writing blocks of data that are larger than the buffer size.
    - Checking the size of the file is correct.
    - Reading small blocks of the file back in and verifying its contents.
    - Reading large blocks of the file back in and verifying its contents.
    Parameters:
    
    filename - the name of the test file to generate.
  - benchmark
```
public static void benchmark(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.

Class RandomAccessFile

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

READ

WRITE

CREATE

defaultBufferSize

file

filePosition

buffer

bufferStart

dataEnd

dataSize

endOfFile

mode

Constructor Detail

RandomAccessFile

RandomAccessFile

RandomAccessFile

RandomAccessFile

RandomAccessFile

Method Detail

close

seek

getFilePointer

length

getFD

flush

read

read

read

readFully

readFully

skipBytes

unread

write

writeBytes

write

write

readBoolean

readByte

readUnsignedByte

readShort

readUnsignedShort

readChar

readInt

readLong

readFloat

readDouble

readLine

readUTF

writeBoolean

writeByte

writeShort

writeChar

writeInt

writeLong

writeFloat

writeDouble

writeBytes

writeBytes

writeChars

writeUTF

toString

testBytes

testBlocks

benchmark