orca.shirako.util
Class BinPool

java.lang.Object
  orca.shirako.util.BinPool

public class BinPool
extends java.lang.Object

This is a utility class for use in mappers: it manages a pool of resource "bins" (any Object), indexed by the number of units allocated or free from each bin.

Constructor Summary

BinPool(int ballsPerBin)

Method Summary

void	addBin(java.lang.Object o) Installs a new bin with all elements free.
void	drainBin(java.lang.Object o, int balls, int draining) Deallocates units from a bin, increasing its number of free units.
void	fillBin(java.lang.Object o, int balls, int filling) Allocates units from/to a bin, reducing the number of free units.
java.lang.Object	findAndFillBin(int balls) Finds a bin with a minimum number of units free, and allocate more units from (to?) it, reducing the number of free units.
int	getBinSize()

Methods inherited from class java.lang.Object

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

Constructor Detail

BinPool

public BinPool(int ballsPerBin)

Method Detail

addBin

public void addBin(java.lang.Object o)

Installs a new bin with all elements free.

Parameters:

o - the bin

drainBin

public void drainBin(java.lang.Object o,
                     int balls,
                     int draining)

Deallocates units from a bin, increasing its number of free units. Note: the names of 'fill' and 'drain' concepts seem bass-ackwards. Fill increases the number of units allocated from the bin, reducing the number of free units. Drain reduces the number of units allocated from the bin, increasing the number of free units. So we have to think of bins as 'holding' the units allocated from them, and 'free' as their remaining capacity. How very strange and confusing.

Parameters:

o - the bin

balls - how many units the bin has free

draining - how many units being restored

fillBin

public void fillBin(java.lang.Object o,
                    int balls,
                    int filling)

Allocates units from/to a bin, reducing the number of free units.

Parameters:

o - the bin

balls - how many units the bin currently has allocated

filling - how many new units being allocated

findAndFillBin

public java.lang.Object findAndFillBin(int balls)
                                throws java.lang.Exception

Finds a bin with a minimum number of units free, and allocate more units from (to?) it, reducing the number of free units.

Parameters:

balls - number of units needed

Returns:

the selected bin

Throws:

java.lang.Exception

getBinSize

public int getBinSize()