RandomAccessFile JDK 1.6)

Value	Meaning
`"r"`	Open for reading only. Invoking any of the `write` methods of the resulting object will cause an `IOException` to be thrown.
`"rw"`	Open for reading and writing. If the file does not already exist then an attempt will be made to create it.
`"rws"`	Open for reading and writing, as with `"rw"`, and also require that every update to the file's content or metadata be written synchronously to the underlying storage device.
`"rwd"`	Open for reading and writing, as with `"rw"`, and also require that every update to the file's content be written synchronously to the underlying storage device.

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public void close () throws IOException [Specified in Closeable]

Closes this random access file stream and releases any system resources associated with the stream.

publicfinal FileChannel getChannel ()

Returns the unique FileChannel object associated with this file.

publicfinal FileDescriptor getFD () throws IOException

Returns the opaque file descriptor object associated with this stream.

publicnative long getFilePointer () throws IOException

Returns the current offset in this file.

publicnative long length () throws IOException

Returns the length of this file.

publicnative int read () throws IOException

Reads a byte of data from this file.

Reads a byte of data from this file. The byte is returned as an integer in the range 0 to 255 (0x00-0x0ff). This method blocks if no input is yet available.

Although RandomAccessFile is not a subclass of InputStream, this method behaves in exactly the same way as the InputStream.read() method of InputStream.
Returns: the next byte of data, or -1 if the end of the file has been reached.
Throws:
- IOException - if an I/O error occurs. Not thrown if end-of-file has been reached.

public int read (byte[] b) throws IOException

Reads up to b.length bytes of data from this file into an array of bytes.

Reads up to b.length bytes of data from this file into an array of bytes. This method blocks until at least one byte of input is available.

Although RandomAccessFile is not a subclass of InputStream, this method behaves in exactly the same way as the InputStream.read(byte[]) method of InputStream.
Returns: the total number of bytes read into the buffer, or -1 if there is no more data because the end of this file has been reached.
Parameters:
- b - the buffer into which the data is read.
Throws:
- IOException - If the first byte cannot be read for any reason other than end of file, or if the random access file has been closed, or if some other I/O error occurs.
- NullPointerException - If b is null.

public int read (byte[] b, int off, int len) throws IOException

Reads up to len bytes of data from this file into an array of bytes.

Reads up to len bytes of data from this file into an array of bytes. This method blocks until at least one byte of input is available.

Although RandomAccessFile is not a subclass of InputStream, this method behaves in exactly the same way as the InputStream.read(byte[], int, int) method of InputStream.
Returns: the total number of bytes read into the buffer, or -1 if there is no more data because the end of the file has been reached.
Parameters:
- b - the buffer into which the data is read.
- off - the start offset in array b at which the data is written.
- len - the maximum number of bytes read.
Throws:
- IOException - If the first byte cannot be read for any reason other than end of file, or if the random access file has been closed, or if some other I/O error occurs.
- NullPointerException - If b is null.
- IndexOutOfBoundsException - If off is negative, len is negative, or len is greater than b.length - off

publicfinal boolean readBoolean () throws IOException [Specified in DataInput]

Reads a boolean from this file.

Reads a boolean from this file. This method reads a
single byte from the file, starting at the current file pointer.
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.
Returns: the boolean value read.
Throws:
- EOFException - if this file has reached the end.
- IOException - if an I/O error occurs.

publicfinal byte readByte () throws IOException [Specified in DataInput]

Reads a signed eight-bit value from this file.

Reads a signed eight-bit value from this file. This method reads a byte from the file, starting from the current file pointer. If the byte read is b, where 0 <= b <= 255, then the result is:

     (byte)(b)

This method blocks until the byte is read, the end of the stream is detected, or an exception is thrown.
Returns: the next byte of this file as a signed eight-bit byte.
Throws:
- EOFException - if this file has reached the end.
- IOException - if an I/O error occurs.

publicfinal char readChar () throws IOException [Specified in DataInput]

Reads a character from this file.

Reads a character from this file. This method reads two bytes from the file, starting at the current file pointer. If the bytes read, in order, are b1 and b2, where 0 <= b1, b2 <= 255, then the result is equal to:

     (char)((b1 << 8) | b2)

This method blocks until the two bytes are read, the end of the stream is detected, or an exception is thrown.
Returns: the next two bytes of this file, interpreted as a char.
Throws:
- EOFException - if this file reaches the end before reading two bytes.
- IOException - if an I/O error occurs.

publicfinal double readDouble () throws IOException [Specified in DataInput]

Reads a double from this file.

Reads a double from this file. This method reads a long value, starting at the current file pointer, 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.
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),

publicfinal float readFloat () throws IOException [Specified in DataInput]

Reads a float from this file.

Reads a float from this file. This method reads an int value, starting at the current file pointer, 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.
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),

publicfinal void readFully (byte[] b) throws IOException [Specified in DataInput]

Reads b.length bytes from this file into the byte array, starting at the current file pointer.

Reads b.length bytes from this file into the byte
array, starting at the current file pointer. This method reads
repeatedly from the file until the requested number of bytes are
read. This method blocks until the requested number of bytes are
read, the end of the stream is detected, or an exception is thrown.
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.

publicfinal void readFully (byte[] b, int off, int len) throws IOException [Specified in DataInput]

Reads exactly len bytes from this file into the byte array, starting at the current file pointer.

Reads exactly len bytes from this file into the byte
array, starting at the current file pointer. This method reads
repeatedly from the file until the requested number of bytes are
read. This method blocks until the requested number of bytes are
read, the end of the stream is detected, or an exception is thrown.
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.

publicfinal int readInt () throws IOException [Specified in DataInput]

Reads a signed 32-bit integer from this file.

Reads a signed 32-bit integer from this file. This method reads 4 bytes from the file, starting at the current file pointer. 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:

     (b1 << 24) | (b2 << 16) + (b3 << 8) + b4

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

publicfinal String readLine () throws IOException [Specified in DataInput]

Reads the next line of text from this file.

publicfinal long readLong () throws IOException [Specified in DataInput]

Reads a signed 64-bit integer from this file.

Reads a signed 64-bit integer from this file. This method reads eight bytes from the file, starting at the current file pointer. If the bytes read, in order, are b1, b2, b3, b4, b5, b6, b7, and b8, where:

     0 <= b1, b2, b3, b4, b5, b6, b7, b8 <=255,

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.
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.

publicfinal short readShort () throws IOException [Specified in DataInput]

Reads a signed 16-bit number from this file.

Reads a signed 16-bit number from this file. The method reads two bytes from this file, starting at the current file pointer. 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:

     (short)((b1 << 8) | b2)

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

publicfinal int readUnsignedByte () throws IOException [Specified in DataInput]

Reads an unsigned eight-bit number from this file.

publicfinal int readUnsignedShort () throws IOException [Specified in DataInput]

Reads an unsigned 16-bit number from this file.

Reads an unsigned 16-bit number from this file. This method reads two bytes from the file, starting at the current file pointer. If the bytes read, in order, are b1 and b2, where 0 <= b1, b2 <= 255, then the result is equal to:

     (b1 << 8) | b2

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

publicfinal String readUTF () throws IOException [Specified in DataInput]

Reads in a string from this file.

publicnative void seek (long pos) throws IOException

Sets the file-pointer offset, measured from the beginning of this file, at which the next read or write occurs.

Sets the file-pointer offset, measured from the beginning of this
file, at which the next read or write occurs. The offset may be
set beyond the end of the file. Setting the offset beyond the end
of the file does not change the file length. The file length will
change only by writing after the offset has been set beyond the end
of the file.
Parameters:
- pos - the offset position, measured in bytes from the beginning of the file, at which to set the file pointer.
Throws:
- IOException - if pos is less than 0 or if an I/O error occurs.

publicnative void setLength (long newLength) throws IOException

Sets the length of this file.

public int skipBytes (int n) throws IOException [Specified in DataInput]

Attempts to skip over n bytes of input discarding the skipped bytes.

This method may skip over some smaller number of bytes, possibly zero. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. This method never throws an EOFException. The actual number of bytes skipped is returned. If n is negative, no bytes are skipped.
Returns: the actual number of bytes skipped.
Parameters:
- n - the number of bytes to be skipped.
Throws:
- IOException - if an I/O error occurs.

public void write (byte[] b) throws IOException [Specified in DataOutput]

Writes b.length bytes from the specified byte array to this file, starting at the current file pointer.

Writes b.length bytes from the specified byte array
to this file, starting at the current file pointer.
Parameters:
- b - the data.
Throws:
- IOException - if an I/O error occurs.

public void write (byte[] b, int off, int len) throws IOException [Specified in DataOutput]

Writes len bytes from the specified byte array starting at offset off to this file.

Writes len bytes from the specified byte array
starting at offset off to this file.
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.

publicnative void write (int b) throws IOException [Specified in DataOutput]

Writes the specified byte to this file.

Writes the specified byte to this file. The write starts at
the current file pointer.
Parameters:
- b - the byte to be written.
Throws:
- IOException - if an I/O error occurs.

publicfinal void writeBoolean (boolean v) throws IOException [Specified in DataOutput]

Writes a boolean to the file as a one-byte value.

Writes a boolean to the file as a one-byte value. The
value true is written out as the value
(byte)1; the value false is written out
as the value (byte)0. The write starts at
the current position of the file pointer.
Parameters:
- v - a boolean value to be written.
Throws:
- IOException - if an I/O error occurs.

publicfinal void writeByte (int v) throws IOException [Specified in DataOutput]

Writes a byte to the file as a one-byte value.

Writes a byte to the file as a one-byte value. The
write starts at the current position of the file pointer.
Parameters:
- v - a byte value to be written.
Throws:
- IOException - if an I/O error occurs.

publicfinal void writeBytes (String s) throws IOException [Specified in DataOutput]

Writes the string to the file as a sequence of bytes.

publicfinal void writeChar (int v) throws IOException [Specified in DataOutput]

Writes a char to the file as a two-byte value, high byte first.

Writes a char to the file as a two-byte value, high
byte first. The write starts at the current position of the
file pointer.
Parameters:
- v - a char value to be written.
Throws:
- IOException - if an I/O error occurs.

publicfinal void writeChars (String s) throws IOException [Specified in DataOutput]

Writes a string to the file as a sequence of characters.

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. The write starts at the current
position of the file pointer.
Parameters:
- s - a String value to be written.
Throws:
- IOException - if an I/O error occurs.
See Also: RandomAccessFile.writeChar(int),

publicfinal void writeDouble (double v) throws IOException [Specified in DataOutput]

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 eight-byte quantity, high byte first.

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
eight-byte quantity, high byte first. The write starts at the current
position of the file pointer.
Parameters:
- v - a double value to be written.
Throws:
- IOException - if an I/O error occurs.
See Also: Double.doubleToLongBits(double),

publicfinal void writeFloat (float v) throws IOException [Specified in DataOutput]

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 four-byte quantity, high byte first.

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
four-byte quantity, high byte first. The write starts at the
current position of the file pointer.
Parameters:
- v - a float value to be written.
Throws:
- IOException - if an I/O error occurs.
See Also: Float.floatToIntBits(float),

publicfinal void writeInt (int v) throws IOException [Specified in DataOutput]

Writes an int to the file as four bytes, high byte first.

Writes an int to the file as four bytes, high byte first.
The write starts at the current position of the file pointer.
Parameters:
- v - an int to be written.
Throws:
- IOException - if an I/O error occurs.

publicfinal void writeLong (long v) throws IOException [Specified in DataOutput]

Writes a long to the file as eight bytes, high byte first.

Writes a long to the file as eight bytes, high byte first.
The write starts at the current position of the file pointer.
Parameters:
- v - a long to be written.
Throws:
- IOException - if an I/O error occurs.

publicfinal void writeShort (int v) throws IOException [Specified in DataOutput]

Writes a short to the file as two bytes, high byte first.

Writes a short to the file as two bytes, high byte first.
The write starts at the current position of the file pointer.
Parameters:
- v - a short to be written.
Throws:
- IOException - if an I/O error occurs.

publicfinal void writeUTF (String str) throws IOException [Specified in DataOutput]

Writes a string to the file using modified UTF-8 encoding in a machine-independent manner.