Strategie
Class Clock

java.lang.Object
  |
  +--Strategie.ReplaceStrategy
        |
        +--Strategie.Clock

public class Clock

extends ReplaceStrategy

This class is an implementation of the abstract class ReplaceStrategy. It simulates the strategy Clock (or Enhanced FIFO). It is based on FIFO. In addition to FIFO, a referenceBit is used, to prefer selecting pages for replacing, that have not been references recently.

Field Summary

static boolean	ISACCESSCOUNT True, when the number of accesses is used by this strategy
static boolean	ISACCESSTIME True, when the access time is used by this strategy
static boolean	ISINSERTIONTIME True, when the insertion time is used by this strategy
static java.lang.String	LONGNAME Long name for this strategy
static int	MODBITCOUNT Initial value for the number of modifyBits
static int	REFBITCOUNT Initial value for the number of referenceBits
static java.lang.String	SHORTNAME Short name for this strategy

Fields inherited from class Strategie.ReplaceStrategy

isAccessCount, isAccessTime, isInsertTime, isShowMemoryDetails, longName, modifyBitCount, referenceBitCount, shortName

Constructor Summary

Clock(boolean showDetails)
Creates a new instance of this strategy

Method Summary

Memory	createMemory(int size, int refBits, int modBits) Creates a new memory structure with the given size and number of reference- and modifyBits
int	getDrawLfdNr(Memory memory, int i) The memory structure can have an strategy-dependant internal sort.
Page	getVictimPage(Memory memory, SimuData simu, GUI gui) Selects the next victim page.
void	replacePage(Memory memory, Page oldPage, Page newPage, SimuData simu, GUI gui) Replaces the oldPage by the newPage in memory
void	setInitVictimPointer(Memory memory) Sets the indexpointer to the page that has to be placed first.
void	sortMemory(Memory memory) Sorts the memory by insertiontime of each page Caution: For a simple solution the old framenumber will be overwritten

Methods inherited from class Strategie.ReplaceStrategy

getLongName, getModifyBitCount, getReferenceBitCount, getShortName, isAccessCount, isAccessTime, isInsertTime, isModifyBit, isReferenceBit, isShowMemoryDetails, reInsertPage, setShowMemoryDetails

Methods inherited from class java.lang.Object

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

Field Detail

SHORTNAME

public static final java.lang.String SHORTNAME

Short name for this strategy

LONGNAME

public static final java.lang.String LONGNAME

Long name for this strategy

REFBITCOUNT

public static final int REFBITCOUNT

Initial value for the number of referenceBits

MODBITCOUNT

public static final int MODBITCOUNT

Initial value for the number of modifyBits

ISACCESSCOUNT

public static final boolean ISACCESSCOUNT

True, when the number of accesses is used by this strategy

ISACCESSTIME

public static final boolean ISACCESSTIME

True, when the access time is used by this strategy

ISINSERTIONTIME

public static final boolean ISINSERTIONTIME

True, when the insertion time is used by this strategy

Constructor Detail

Clock

public Clock(boolean showDetails)

Creates a new instance of this strategy

Method Detail

createMemory

public Memory createMemory(int size,
                           int refBits,
                           int modBits)

Creates a new memory structure with the given size and number of reference- and modifyBits

Overrides:

createMemory in class ReplaceStrategy

setInitVictimPointer

public void setInitVictimPointer(Memory memory)

Sets the indexpointer to the page that has to be placed first. Only needed at the beginning when creating new memory

Overrides:

setInitVictimPointer in class ReplaceStrategy

sortMemory

public void sortMemory(Memory memory)

Sorts the memory by insertiontime of each page Caution: For a simple solution the old framenumber will be overwritten

Overrides:

sortMemory in class ReplaceStrategy

getDrawLfdNr

public int getDrawLfdNr(Memory memory,
                        int i)

The memory structure can have an strategy-dependant internal sort. This function returns the index in memory structure where the frame i is stored. This is needed for drawing the memory details in the strategy-dependant order.

Overrides:

getDrawLfdNr in class ReplaceStrategy

getVictimPage

public Page getVictimPage(Memory memory,
                          SimuData simu,
                          GUI gui)

Selects the next victim page. The victim page is the first that can be found in
- class 1: referenceBits are not set, else
- class 2: any page

Overrides:

getVictimPage in class ReplaceStrategy

replacePage

public void replacePage(Memory memory,
                        Page oldPage,
                        Page newPage,
                        SimuData simu,
                        GUI gui)

Replaces the oldPage by the newPage in memory

Overrides:

replacePage in class ReplaceStrategy