com.terracottatech.offheapstore.filesystem.impl

Class OffheapOutputStream

java.lang.Object

java.io.OutputStream

com.terracottatech.offheapstore.filesystem.SeekableOutputStream

com.terracottatech.offheapstore.filesystem.impl.OffheapOutputStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable

public class OffheapOutputStream
extends SeekableOutputStream

Each file is made up of multiple blocks of size BLOCK_SIZE. There are two pointers to track the writes:

1. The currentBufferIndex tracks the block number which should be written to.
2. The currentBuffer is the actual block to which the bytes are written. It is a simple ByteBuffer.

The actual position at which the next byte is written, from the beginning of the file is: (currentBufferIndex * BLOCK_SIZE) + currentBuffer.position()

Method Summary

Modifier and Type	Method and Description
void	close()
void	flush()
long	getFilePointer() Returns the current offset in this file.
long	length() Returns the length of the stream.
void	reset() Resets this to an empty file.
void	seek(long pos) Sets the file-pointer offset, measured from the beginning of this file, at which the next write occurs.
long	sizeInBytes() Returns byte usage of all buffers.
String	toString()
void	write(byte[] b, int offset, int len)
void	write(int b)

Methods inherited from class java.io.OutputStream

write

Methods inherited from class java.lang.Object

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

Method Detail

write

public void write(int b)
           throws IOException

Description copied from class: SeekableOutputStream

Specified by:

write in class SeekableOutputStream

Throws:

IOException

write

public void write(byte[] b,
                  int offset,
                  int len)
           throws IOException

Overrides:

write in class OutputStream

Throws:

IOException

reset

public void reset()
           throws IOException

Resets this to an empty file.

Specified by:

reset in class SeekableOutputStream

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class OutputStream

Throws:

IOException

seek

public void seek(long pos)
          throws IOException

Description copied from class: SeekableOutputStream

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

Specified by:

seek in class SeekableOutputStream

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.

toString

public String toString()

Overrides:

toString in class Object

length

public long length()
            throws IOException

Description copied from class: SeekableOutputStream

Returns the length of the stream. This method flushes the buffers to the file before calculating the length.

Specified by:

length in class SeekableOutputStream

Returns:

length of the stream in bytes

Throws:

IOException

flush

public void flush()
           throws IOException

Specified by:

flush in interface Flushable

Overrides:

flush in class OutputStream

Throws:

IOException

getFilePointer

public long getFilePointer()

Description copied from class: SeekableOutputStream

Returns the current offset in this file.

Specified by:

getFilePointer in class SeekableOutputStream

Returns:

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

sizeInBytes

public long sizeInBytes()

Returns byte usage of all buffers.