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

java.lang.Object
  |
  +--edu.utah.janosvm.sys.ListNode
        |
        +--edu.utah.janosvm.sys.Importable
              |
              +--edu.utah.janosvm.kit.server.memfs.MemoryBlock

final class MemoryBlock

extends Importable

A fault tolerant handle for a MemoryBlockBackEnd.

Field Summary

private MemoryBlockBackEnd	be The exportable.
private static long	CONNECT_DELAY The number of milliseconds to wait before retrying to connect to the server.
private static int	CONNECT_RETRIES The number of times to try connecting to the server.
private java.lang.String	fileName The name of the block to import.
private static java.lang.Class	THIS_CLASS Pointer to this class, used for set/getClassLocal.

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

em

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

pred, succ

Constructor Summary

(package private)

MemoryBlock(java.lang.String fileName) Construct a MemoryBlock handle that will import the MemoryBlockBackEnd with the given name.

Method Summary

protected void	bindTo(Exportable ex) Bind this Importable to the given Exportable.
(package private) void	connect(boolean create) A fault tolerant method for connecting to the server and the exported object.
(package private) boolean	delete()
(package private) boolean	isConnected()
(package private) int	read(int cursor, byte[] buffer, int offset, int length)
(package private) void	sync() Force a write to disk of the whole MemoryFileSystem.
java.lang.String	toString()
protected void	unbindFrom() Unbind this Importable from any objects it is referencing.
(package private) void	write(int cursor, byte[] buffer, int offset, int length)

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

copy, finalize, getExportManager, revoke, setExportManager

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

append, clone, inList, prepend, remove

Methods inherited from class java.lang.Object

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

Field Detail

THIS_CLASS

private static final java.lang.Class THIS_CLASS

Pointer to this class, used for set/getClassLocal.

CONNECT_DELAY

private static final long CONNECT_DELAY

The number of milliseconds to wait before retrying to connect to the server.

CONNECT_RETRIES

private static final int CONNECT_RETRIES

The number of times to try connecting to the server.

fileName

private final java.lang.String fileName

The name of the block to import.

be

private MemoryBlockBackEnd be

The exportable.

Constructor Detail

MemoryBlock

MemoryBlock(java.lang.String fileName)

Construct a MemoryBlock handle that will import the MemoryBlockBackEnd with the given name.

Parameters:

fileName - The name of the MemoryBlockBackEnd to import.

Method Detail

bindTo

protected void bindTo(Exportable ex)

Description copied from class: Importable

Bind this Importable to the given Exportable. The most common implementation of this method would be to cast the Exportable to the type that the Importable subclass handles and store it in the object as well as any other handy pointers/values.

This method will be invoked as a side-effect of binding this importable to an Exportable object via TeamHandle.importObject(edu.utah.janosvm.sys.Importable, java.lang.Object).

XXX Add note about synchronized.

Overrides:

bindTo in class Importable

Following copied from class: edu.utah.janosvm.sys.Importable

Parameters:

ex - The Exportable that is being imported.

unbindFrom

protected void unbindFrom()

Description copied from class: Importable

Unbind this Importable from any objects it is referencing. The most common implementation of this method would be null out any object references in this object.

This method will be invoked as a side-effect of canceling this import, or when the Team owning the Exportable is terminated, or when the Exportable is revoked.

XXX rename to just 'unbind'.

Overrides:

unbindFrom in class Importable

Following copied from class: edu.utah.janosvm.sys.Importable

See Also:

TeamHandle.cancelImport(edu.utah.janosvm.sys.Importable), Team.revokeObject(java.lang.Object), TeamHandle.terminate()

isConnected

boolean isConnected()

Returns:

True if the handle is connected to an export.

connect

void connect(boolean create)
       throws java.io.FileNotFoundException

A fault tolerant method for connecting to the server and the exported object.

Parameters:

create - Create the object if it doesn't already exist.

Throws:

Throws - FileNotFoundException if the file couldn't be found and create is false or if the method was unable to connect to the server.

read

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

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.

Throws:

Throws - a DeadTeamException if the import has been revoked.

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.

Throws:

Throws - a DeadTeamException if the import has been revoked or the server team is unreachable.

Throws - a TeamEjectionException if the thread was ejected during processing.

delete

boolean delete()
         throws DeadTeamException,
                TeamEjectionException

Returns:

True if the file was deleted from the file system.

sync

void sync()
    throws DeadTeamException,
           TeamEjectionException,
           java.io.IOException

Force a write to disk of the whole MemoryFileSystem.

toString

public java.lang.String toString()

Overrides:

toString in class Importable