bufmgr
Class Replacer

java.lang.Object
  global.AbstractBufMgrReplacer
      bufmgr.Replacer

All Implemented Interfaces:

GlobalConst

Direct Known Subclasses:

Clock

public abstract class Replacer

extends AbstractBufMgrReplacer

Field Summary

Fields inherited from class global.AbstractBufMgrReplacer

Available, Pinned, Referenced

Fields inherited from interface global.GlobalConst

INVALID_PAGE, MAX_NAME, MAXATTRNAME, MAXFILENAME, MAXINDEXNAME, MINIBASE_BUFFER_POOL_SIZE, MINIBASE_DB_SIZE, MINIBASE_DEFAULT_SHAREDMEM_SIZE, MINIBASE_MAX_TRANSACTIONS, MINIBASE_MAXARRSIZE, NUMBUF, PAGE_SIZE, PAGESIZE

Constructor Summary

Replacer()

Replacer(AbstractBufMgr javamgr)

Method Summary

void	free(int frameNo) Frees and unpins a page in the buffer pool.
int	getNumUnpinnedBuffers() Counts the unpinned frames (free frames) in the buffer pool.
void	info() Prints out the information of the buffer frame.
void	pin(int frameNo) Pins a candidate page in the buffer pool.
boolean	unpin(int frameNo) Unpins a page in the buffer pool.

Methods inherited from class global.AbstractBufMgrReplacer

name, pick_victim, setBufferManager

Methods inherited from class java.lang.Object

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

Constructor Detail

Replacer

public Replacer()

Replacer

public Replacer(AbstractBufMgr javamgr)

Method Detail

pin

public void pin(int frameNo)
         throws InvalidFrameNumberException

Pins a candidate page in the buffer pool.

Specified by:

pin in class AbstractBufMgrReplacer

Parameters:

frameNo - frame number of the page.

Returns:

true if successful.

Throws:

InvalidFrameNumberException - if the frame number is less than zero or bigger than number of buffers.

unpin

public boolean unpin(int frameNo)
              throws InvalidFrameNumberException,
                     PageUnpinnedException

Unpins a page in the buffer pool.

Specified by:

unpin in class AbstractBufMgrReplacer

Parameters:

frameNo - frame number of the page.

Returns:

true if successful.

Throws:

InvalidFrameNumberException - if the frame number is less than zero or bigger than number of buffers.

PageUnpinnedException - if the page is originally unpinned.

free

public void free(int frameNo)
          throws PagePinnedException

Frees and unpins a page in the buffer pool.

Specified by:

free in class AbstractBufMgrReplacer

Parameters:

frameNo - frame number of the page.

Throws:

PagePinnedException - if the page is pinned.

info

public void info()

Prints out the information of the buffer frame.

getNumUnpinnedBuffers

public int getNumUnpinnedBuffers()

Counts the unpinned frames (free frames) in the buffer pool.

Specified by:

getNumUnpinnedBuffers in class AbstractBufMgrReplacer