simpledb.tx
Class BufferList

java.lang.Object
  simpledb.tx.BufferList

 class BufferList
extends java.lang.Object

Manages the transaction's currently-pinned buffers.

Author:

Edward Sciore

Constructor Summary

BufferList()

Method Summary

(package private) Buffer	getBuffer(Block blk) Returns the buffer pinned to the specified block.
(package private) void	pin(Block blk) Pins the block and keeps track of the buffer internally.
(package private) Block	pinNew(java.lang.String filename, PageFormatter fmtr) Appends a new block to the specified file and pins it.
(package private) void	unpin(Block blk) Unpins the specified block.
(package private) void	unpinAll() Unpins any buffers still pinned by this transaction.

Methods inherited from class java.lang.Object

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

Constructor Detail

BufferList

BufferList()

Method Detail

getBuffer

Buffer getBuffer(Block blk)

Returns the buffer pinned to the specified block. The method returns null if the transaction has not pinned the block.

Parameters:

blk - a reference to the disk block

Returns:

the buffer pinned to that block

pin

void pin(Block blk)

Pins the block and keeps track of the buffer internally.

Parameters:

blk - a reference to the disk block

pinNew

Block pinNew(java.lang.String filename,
             PageFormatter fmtr)

Appends a new block to the specified file and pins it.

Parameters:

filename - the name of the file

fmtr - the formatter used to initialize the new page

Returns:

a reference to the newly-created block

unpin

void unpin(Block blk)

Unpins the specified block.

Parameters:

blk - a reference to the disk block

unpinAll

void unpinAll()

Unpins any buffers still pinned by this transaction.