edu.utah.janosvm.kit.server.memfs
Class MemoryBlockBackEnd

java.lang.Object
  |
  +--edu.utah.janosvm.sys.Exportable
        |
        +--edu.utah.janosvm.kit.server.memfs.MemoryBlockBackEnd

All Implemented Interfaces:

TemporaryExport

final class MemoryBlockBackEnd

extends Exportable

implements TemporaryExport

The object representing a file in the memory file system.

Field Summary

private int	actual The actual size of the file.
private byte[]	data The file data.
(package private) static int	DEFAULT_BLOCK_SIZE The size of blocks allocated by the object.
private boolean	expired Indicates whether or not the block has been deleted.

Fields inherited from class edu.utah.janosvm.sys.Exportable

anonManager, owner

Constructor Summary

(package private)	MemoryBlockBackEnd() Construct an empty block.
(package private)	MemoryBlockBackEnd(byte[] data, int actual) Construct a block with the given values.

Method Summary

(package private) static int	blockCount(int size)
boolean	expired() This method is called when there are no more imports for the export.
(package private) int	getActual()
(package private) byte[]	getData()
java.lang.Object	getName() Used to determine the name of this TemporaryObject object during revocation.
(package private) int	read(int cursor, byte[] buffer, int offset, int length)
(package private) void	setExpired(boolean expired)
java.lang.String	toString()
(package private) void	write(int cursor, byte[] buffer, int offset, int length)

Methods inherited from class edu.utah.janosvm.sys.Exportable

getAnonymousManager, pushOwnerReservation, returnFromOwner, setAnonymousManager, switchToOwner

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait, wait0

Field Detail

DEFAULT_BLOCK_SIZE

static final int DEFAULT_BLOCK_SIZE

The size of blocks allocated by the object.

expired

private boolean expired

Indicates whether or not the block has been deleted. Used to answer the expired() question asked by the ExportManager when the last import is removed.

data

private byte[] data

The file data.

actual

private int actual

The actual size of the file.

Constructor Detail

MemoryBlockBackEnd

MemoryBlockBackEnd()

Construct an empty block.

MemoryBlockBackEnd

MemoryBlockBackEnd(byte[] data,
                   int actual)

Construct a block with the given values.

Parameters:

data - A block aligned byte array containing the file data.

actual - The actual size of the data.

Method Detail

blockCount

static int blockCount(int size)

Parameters:

size - The number of bytes that needs to be contained in blocks.

Returns:

The number of blocks needed to contain `size'.

getName

public java.lang.Object getName()

Description copied from interface: TemporaryExport

Used to determine the name of this TemporaryObject object during revocation. Should return null for an anonymous export.

Specified by:

getName in interface TemporaryExport

getData

byte[] getData()

Returns:

A block aligned byte array containing the file data.

getActual

int getActual()

Returns:

The actual size of the data.

read

int read(int cursor,
         byte[] buffer,
         int offset,
         int length)

Parameters:

cursor - The offset to read from the file.

buffer - The buffer to read the data into.

offset - The offset into buffer to start reading.

length - The number of bytes to read into buffer.

Returns:

The number of bytes read.

write

void write(int cursor,
           byte[] buffer,
           int offset,
           int length)
     throws DeadTeamException,
            TeamEjectionException

Parameters:

cursor - The offset to start writing into the file.

buffer - The buffer to read the data to write.

offset - The offset into buffer to start reading.

length - The number of bytes to write into buffer.

setExpired

void setExpired(boolean expired)

Parameters:

expired - The new value of the expired field.

expired

public boolean expired()

Description copied from interface: TemporaryExport

This method is called when there are no more imports for the export. If it returns true than the export is revoked otherwise it will continue to be available for importing.

Specified by:

expired in interface TemporaryExport

Following copied from interface: edu.utah.janosvm.sys.TemporaryExport

Returns:

True if the export has expired and should be revoked.

toString

public java.lang.String toString()

Overrides:

toString in class Exportable