org.jikesrvm.mm.mmtk

Class FinalizableProcessor

java.lang.Object

org.mmtk.vm.FinalizableProcessor

org.jikesrvm.mm.mmtk.FinalizableProcessor

public final class FinalizableProcessor
extends FinalizableProcessor

This class manages the processing of finalizable objects.

TODO can this be a linked list?

Field Summary

Fields

Modifier and Type	Field and Description
private static FinalizableProcessor	finalizableProcessor The FinalizableProcessor singleton
private static double	GROWTH_FACTOR Amount to grow the table by when it is filled
private static int	INITIAL_SIZE Initial size of the reference object table
private int	lastReadyIndex Last object ready to be finalized
private Lock	lock Used to ensure mutual exclusion during table manipulation
protected int	maxIndex Index of the first free slot in the table.
private int	nextReadyIndex Next object ready to be finalized
protected int	nurseryIndex Index of first entry created since last collection
protected Object[]	readyForFinalize The table of ready objects
private static boolean	STRESS Stress the system?
protected AddressArray	table The table of candidates

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	FinalizableProcessor() Create a new table.

Method Summary

Modifier and Type	Method and Description
void	add(Object object) Allocate an entry in the table.
static void	addCandidate(Object object) Add a finalization candidate.
void	clear() Clear the contents of the table.
int	count()
int	countReady()
static int	countReadyForFinalize()
void	forward(TraceLocal trace, boolean nursery) Iterates over and forward entries in the table.
int	freeReady()
static Object	getForFinalize()
static FinalizableProcessor	getProcessor()
Object	getReady() Get an object to run finalize().
void	scan(TraceLocal trace, boolean nursery) Scan through the list of references.

Methods inherited from class java.lang.Object

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

Field Detail

finalizableProcessor

private static final FinalizableProcessor finalizableProcessor

The FinalizableProcessor singleton

STRESS

private static final boolean STRESS

Stress the system?

See Also:

Constant Field Values

INITIAL_SIZE

private static final int INITIAL_SIZE

Initial size of the reference object table

See Also:

Constant Field Values

GROWTH_FACTOR

private static final double GROWTH_FACTOR

Amount to grow the table by when it is filled

See Also:

Constant Field Values

lock

private final Lock lock

Used to ensure mutual exclusion during table manipulation

table

protected volatile AddressArray table

The table of candidates

readyForFinalize

protected volatile Object[] readyForFinalize

The table of ready objects

nurseryIndex

protected int nurseryIndex

Index of first entry created since last collection

maxIndex

protected volatile int maxIndex

Index of the first free slot in the table.

nextReadyIndex

private volatile int nextReadyIndex

Next object ready to be finalized

lastReadyIndex

private volatile int lastReadyIndex

Last object ready to be finalized

Constructor Detail

FinalizableProcessor

protected FinalizableProcessor()

Create a new table.

Method Detail

add

public void add(Object object)

Allocate an entry in the table. This should be called from an unpreemptible context so that the entry can be filled. This method is responsible for growing the table if necessary.

Parameters:

object - the object to add to the table of candidates

clear

public void clear()

Description copied from class: FinalizableProcessor

Clear the contents of the table. This is called when finalization is disabled to make it easier for VMs to change this setting at runtime.

Specified by:

clear in class FinalizableProcessor

forward

public void forward(TraceLocal trace,
                    boolean nursery)

Iterates over and forward entries in the table..

Currently ignores the nursery hint.

TODO parallelise this code?

Specified by:

forward in class FinalizableProcessor

Parameters:

trace - The trace

nursery - Is this a nursery collection ?

scan

public void scan(TraceLocal trace,
                 boolean nursery)

Scan through the list of references. Calls ReferenceProcessor's processReference method for each reference and builds a new list of those references still active.

Depending on the value of nursery, we will either scan all references, or just those created since the last scan.

TODO parallelise this code

Specified by:

scan in class FinalizableProcessor

Parameters:

nursery - Scan only the newly created references

trace - the thread local trace element.

getReady

public Object getReady()

Get an object to run finalize().

Returns:

The object to finalize()

count

public int count()

Returns:

the number of entries in the table.

countReady

public int countReady()

Returns:

the number of entries ready to be finalized.

freeReady

public int freeReady()

Returns:

the number of entries ready to be finalized.

getProcessor

public static FinalizableProcessor getProcessor()

Returns:

the processor singleton

addCandidate

public static void addCandidate(Object object)

Add a finalization candidate.

Parameters:

object - The object with a finalizer.

getForFinalize

public static Object getForFinalize()

Returns:

an object to call the finalize() method on it

countReadyForFinalize

public static int countReadyForFinalize()

Returns:

the number of objects waiting for finalize() calls.