com.jscape.inet.file
Interface JRandomAccessFile

public interface JRandomAccessFile

Instances of this interface support both reading and writing to a random access file. A random access file behaves like a large array of bytes stored in the file system. There is a kind of cursor, or index into the implied array, called the file pointer; input operations read bytes starting at the file pointer and advance the file pointer past the bytes read. If the random access file is created in read/write mode, then output operations are also available; output operations write bytes starting at the file pointer and advance the file pointer past the bytes written. Output operations that write past the current end of the implied array cause the array to be extended. The file pointer can be read by the getFilePointer method and set by the seek method.

Version:

1.0

Author:

Alex Usun

Method Summary

void	close() Closes this random access file stream and releases any system resources associated with the stream.
JFile	getFile() Returns JFile instance associated with this object.
long	getFilePointer() Returns the current offset in this file.
int	read() Reads a byte of data from this file.
int	read(byte[] b) Reads up to b.length bytes of data from this file into an array of bytes.
int	read(byte[] b, int off, int len) Reads up to len bytes of data from this file into an array of bytes.
void	setFilePointer(long filePointer) Sets the file-pointer offset, measured from the beginning of this file, at which the next read or write occurs.
void	write(byte[] b) Writes b.length bytes from the specified byte array to this file, starting at the current file pointer.
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) Writes the specified byte to this file.

Method Detail

close

void close()
           throws java.io.IOException

Closes this random access file stream and releases any system resources associated with the stream. A closed random access file cannot perform input or output operations and cannot be reopened.

Throws:

java.io.IOException - if an I/O error occurred

getFilePointer

long getFilePointer()
                    throws java.io.IOException

Returns the current offset in this file.

Returns:

the offset from the beginning of the file, in bytes, at which the next read or write occurs

Throws:

java.io.IOException - if an I/O error occurred

setFilePointer

void setFilePointer(long filePointer)
                    throws java.io.IOException

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:

filePointer - the offset position, measured in bytes from the beginning of the file, at which to set the file pointer

Throws:

java.io.IOException - if an I/O error occurred

read

int read()
         throws java.io.IOException

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.

Returns:

the next byte of data, or -1 if the end of the file has been reached.

Throws:

java.io.IOException - if an I/O error occurred

read

int read(byte[] b)
         throws java.io.IOException

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.

Parameters:

b - the buffer into which the data is read

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.

Throws:

java.io.IOException - if an I/O error occurred

read

int read(byte[] b,
         int off,
         int len)
         throws java.io.IOException

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.

Parameters:

b - the buffer into which the data is read

off - the start offset of the data

len - the maximum number of bytes read

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

Throws:

java.io.IOException - if an I/O error occurred

write

void write(int b)
           throws java.io.IOException

Writes the specified byte to this file. The write starts at the current file pointer.

Parameters:

b - the byte to be written

Throws:

java.io.IOException - if an I/O error occurred

write

void write(byte[] b)
           throws java.io.IOException

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

Parameters:

b - the data

Throws:

java.io.IOException - if an I/O error occurred

write

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.

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 occurred

getFile

JFile getFile()

Returns JFile instance associated with this object.

Returns:

returns JFile instance