Class GCObjectModel

java.lang.Object

com.ibm.j9ddr.vm29.j9.gc.GCBase

com.ibm.j9ddr.vm29.j9.gc.GCObjectModel

public abstract class GCObjectModel
extends GCBase

Field Summary

Fields

Modifier and Type	Field	Description
protected com.ibm.j9ddr.vm29.j9.gc.GCArrayObjectModel	indexableObjectModel
protected com.ibm.j9ddr.vm29.j9.gc.GCMixedObjectModel	mixedObjectModel

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	GCObjectModel()

Method Summary

Modifier and Type	Method	Description
abstract UDATA	adjustSizeInBytes(UDATA sizeInBytes)	Object size should be at least minimumConsumedSize and 8 byte aligned.
static GCObjectModel	from()	Factory method to construct an appropriate object model.
abstract U32	getAge(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Returns the age of an object.
abstract UDATA	getClassShape(com.ibm.j9ddr.vm29.pointer.generated.J9ClassPointer clazz)	Returns the shape of a class.
abstract UDATA	getClassShape(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Returns the shape of an object.
abstract UDATA	getConsumedSizeInBytesWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Same as getSizeInBytesWithHeader, except it takes into account object alignment and minimum object size
UDATA	getConsumedSizeInSlotsWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Same as getSizeInSlotsWithHeader, except it takes into account object alignment and minimum object size
UDATA	getDataSizeInBytes(com.ibm.j9ddr.vm29.pointer.generated.J9IndexableObjectPointer array)	Returns the size of data in an indexable object, in bytes, including leaves, excluding the header.
abstract VoidPointer	getElementAddress(com.ibm.j9ddr.vm29.pointer.generated.J9IndexableObjectPointer indexableObjectPointer, int elementIndex, int elementSize)	Returns the address of the element at elementIndex logical offset into indexableObjectPointer, assuming that each element is dataSize bytes.
abstract UDATA	getHashcodeOffset(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
abstract UDATA	getHeaderSize(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Returns the size of an object header, in bytes.
abstract long	getObjectAlignmentInBytes()	Returns run-time object alignment in bytes.
abstract I32	getObjectHashCode(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Determine the basic hash code for the specified object.
abstract UDATA	getRememberedBits(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Returns the collector bits from object's header.
abstract long	getScanType(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
abstract UDATA	getSizeInBytesHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Returns the size in bytes of a hole object.
abstract UDATA	getSizeInBytesMultiSlotHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Returns the size, in bytes, of a multi-slot hole object.
abstract UDATA	getSizeInBytesSingleSlotHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Returns the size, in bytes, of a single slot hole object.
abstract UDATA	getSizeInBytesWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Returns the size of an object, in bytes, including the header.
abstract UDATA	getSizeInElements(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Returns the size of an indexable object in elements.
UDATA	getSizeInSlotsWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Returns the size of an object, in slots, including the header.
abstract UDATA	getTotalFootprintInBytesWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Get the total footprint of an object, in bytes, including the object header and all data.
abstract boolean	hasBeenHashed(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Returns TRUE if an object has been hashed, FALSE otherwise.
abstract boolean	hasBeenMoved(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Returns TRUE if an object has been moved after being hashed, FALSE otherwise.
abstract boolean	isDarkMatterObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Returns TRUE if an object is dark matter, FALSE otherwise.
abstract boolean	isHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Returns TRUE if an object is a hole, FALSE otherwise.
abstract boolean	isIndexable(com.ibm.j9ddr.vm29.pointer.generated.J9ClassPointer clazz)	Returns TRUE if an class is indexable, FALSE otherwise.
abstract boolean	isIndexable(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Returns TRUE if an object is indexable, FALSE otherwise.
boolean	isInlineContiguousArraylet(com.ibm.j9ddr.vm29.pointer.generated.J9IndexableObjectPointer arrayPtr)
abstract boolean	isOld(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Returns TRUE if an object is old, FALSE otherwise.
abstract boolean	isRemembered(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Returns TRUE if an object is remembered, FALSE otherwise.
abstract boolean	isSingleSlotHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)	Returns TRUE if an object is a single slot hole object, FALSE otherwise.

Methods declared in class com.ibm.j9ddr.vm29.j9.gc.GCBase

getExtensions, getJavaVM

Methods declared in class java.lang.Object

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

Field Details

mixedObjectModel

protected com.ibm.j9ddr.vm29.j9.gc.GCMixedObjectModel mixedObjectModel

indexableObjectModel

protected com.ibm.j9ddr.vm29.j9.gc.GCArrayObjectModel indexableObjectModel

Constructor Details

GCObjectModel

protected GCObjectModel()
                 throws CorruptDataException

Throws:

CorruptDataException

Method Details

from

public static GCObjectModel from()
                          throws CorruptDataException

Factory method to construct an appropriate object model.

Parameters:

structure - the J9JavaVM structure to use

Returns:

an instance of ObjectModel

Throws:

CorruptDataException

adjustSizeInBytes

public abstract UDATA adjustSizeInBytes(UDATA sizeInBytes)

Object size should be at least minimumConsumedSize and 8 byte aligned.

Parameters:

sizeInBytes - Real size of an object

Returns:

Adjusted size

getClassShape

public abstract UDATA getClassShape(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                             throws CorruptDataException

Returns the shape of an object.

Parameters:

object - Pointer to object whose shape is required.

Returns:

The shape of the object

Throws:

CorruptDataException

getClassShape

public abstract UDATA getClassShape(com.ibm.j9ddr.vm29.pointer.generated.J9ClassPointer clazz)
                             throws CorruptDataException

Returns the shape of a class.

Parameters:

clazz - Pointer to J9ClassPointer whose shape is required.

Returns:

The shape of the class

Throws:

CorruptDataException

isIndexable

public abstract boolean isIndexable(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                             throws CorruptDataException

Returns TRUE if an object is indexable, FALSE otherwise.

Parameters:

object - Pointer to an object

Returns:

TRUE if an object is indexable, FALSE otherwise

Throws:

CorruptDataException

isIndexable

public abstract boolean isIndexable(com.ibm.j9ddr.vm29.pointer.generated.J9ClassPointer clazz)
                             throws CorruptDataException

Returns TRUE if an class is indexable, FALSE otherwise.

Parameters:

clazz - Pointer to an J9Class

Returns:

TRUE if an class is indexable, FALSE otherwise

Throws:

CorruptDataException

isHoleObject

public abstract boolean isHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                              throws CorruptDataException

Returns TRUE if an object is a hole, FALSE otherwise.

Parameters:

object - Pointer to an object

Returns:

TRUE if an object is a hole, FALSE otherwise

Throws:

CorruptDataException

isSingleSlotHoleObject

public abstract boolean isSingleSlotHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                                        throws CorruptDataException

Returns TRUE if an object is a single slot hole object, FALSE otherwise.

Parameters:

object - Pointer to an object

Returns:

TRUE if an object is a single slot hole object, FALSE otherwise

Throws:

CorruptDataException

getSizeInBytesMultiSlotHoleObject

public abstract UDATA getSizeInBytesMultiSlotHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                                                 throws CorruptDataException

Returns the size, in bytes, of a multi-slot hole object.

Parameters:

object - Pointer to an object

Returns:

The size, in bytes, of a multi-slot hole object

Throws:

CorruptDataException

getSizeInBytesSingleSlotHoleObject

public abstract UDATA getSizeInBytesSingleSlotHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)

Returns the size, in bytes, of a single slot hole object.

Parameters:

object - Pointer to an object

Returns:

The size, in bytes, of a single slot hole object

getObjectAlignmentInBytes

public abstract long getObjectAlignmentInBytes()

Returns run-time object alignment in bytes.

Returns:

The alignment in bytes

getSizeInBytesHoleObject

public abstract UDATA getSizeInBytesHoleObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                                        throws CorruptDataException

Returns the size in bytes of a hole object.

Parameters:

object - Pointer to an object

Returns:

The size in bytes of a hole object

Throws:

CorruptDataException

isDarkMatterObject

public abstract boolean isDarkMatterObject(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                                    throws CorruptDataException

Returns TRUE if an object is dark matter, FALSE otherwise.

Parameters:

object - Pointer to an object

Returns:

TRUE if an object is dark matter, FALSE otherwise

Throws:

CorruptDataException

getSizeInBytesWithHeader

public abstract UDATA getSizeInBytesWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                                        throws CorruptDataException

Returns the size of an object, in bytes, including the header.

Parameters:

object - Pointer to an object

Returns:

The size of an object, in bytes, including the header

Throws:

CorruptDataException

getTotalFootprintInBytesWithHeader

public abstract UDATA getTotalFootprintInBytesWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                                                  throws CorruptDataException

Get the total footprint of an object, in bytes, including the object header and all data. If the object has a discontiguous representation, this method should return the size of the root object plus the total of all the discontiguous parts of the object.

Parameters:

object - Pointer to an object

Returns:

the total size of an object, in bytes, including discontiguous parts

Throws:

CorruptDataException

getConsumedSizeInBytesWithHeader

public abstract UDATA getConsumedSizeInBytesWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                                                throws CorruptDataException

Same as getSizeInBytesWithHeader, except it takes into account object alignment and minimum object size

Parameters:

object - Pointer to an object

Returns:

The consumed heap size of an object, in bytes, including the header

Throws:

CorruptDataException

getSizeInSlotsWithHeader

public UDATA getSizeInSlotsWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                               throws CorruptDataException

Returns the size of an object, in slots, including the header.

Parameters:

object - Pointer to an object

Returns:

The size of an object, in slots, including the header

Throws:

CorruptDataException

getConsumedSizeInSlotsWithHeader

public UDATA getConsumedSizeInSlotsWithHeader(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                                       throws CorruptDataException

Same as getSizeInSlotsWithHeader, except it takes into account object alignment and minimum object size

Parameters:

object - Pointer to an object

Returns:

The consumed heap size of an object, in slots, including the header

Throws:

CorruptDataException

getAge

public abstract U32 getAge(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                    throws CorruptDataException

Returns the age of an object.

Parameters:

object - Pointer to an object

Returns:

The age of the object

Throws:

CorruptDataException

isRemembered

public abstract boolean isRemembered(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                              throws CorruptDataException

Returns TRUE if an object is remembered, FALSE otherwise.

Parameters:

object - Pointer to an object

Returns:

TRUE if an object is remembered, FALSE otherwise

Throws:

CorruptDataException

getRememberedBits

public abstract UDATA getRememberedBits(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                                 throws CorruptDataException

Returns the collector bits from object's header.

Parameters:

object - Pointer to an object

Returns:

collector bits

Throws:

CorruptDataException

isOld

public abstract boolean isOld(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                       throws CorruptDataException

Returns TRUE if an object is old, FALSE otherwise.

Parameters:

object - Pointer to an object

Returns:

TRUE if an object is in the old area, FALSE otherwise

Throws:

CorruptDataException

getSizeInElements

public abstract UDATA getSizeInElements(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                                 throws IllegalArgumentException,
CorruptDataException

Returns the size of an indexable object in elements.

Parameters:

array - Pointer to the indexable object whose size is required

Returns:

Size of object in elements

Throws:

IllegalArgumentException - if the object is not an array

CorruptDataException

getScanType

public abstract long getScanType(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                          throws CorruptDataException

Throws:

CorruptDataException

hasBeenHashed

public abstract boolean hasBeenHashed(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                               throws CorruptDataException

Returns TRUE if an object has been hashed, FALSE otherwise.

Parameters:

object - Pointer to an object

Returns:

TRUE if an object has been hashed, FALSE otherwise

Throws:

CorruptDataException

hasBeenMoved

public abstract boolean hasBeenMoved(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                              throws CorruptDataException

Returns TRUE if an object has been moved after being hashed, FALSE otherwise.

Parameters:

object - Pointer to an object

Returns:

TRUE if an object has been moved after being hashed, FALSE otherwise

Throws:

CorruptDataException

getObjectHashCode

public abstract I32 getObjectHashCode(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                               throws CorruptDataException

Determine the basic hash code for the specified object.

Parameters:

object - [in] the object to be hashed

Returns:

the persistent, basic hash code for the object

Throws:

CorruptDataException

getHashcodeOffset

public abstract UDATA getHashcodeOffset(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                                 throws CorruptDataException

Throws:

CorruptDataException

getDataSizeInBytes

public UDATA getDataSizeInBytes(com.ibm.j9ddr.vm29.pointer.generated.J9IndexableObjectPointer array)
                         throws CorruptDataException

Returns the size of data in an indexable object, in bytes, including leaves, excluding the header.

Parameters:

array - Pointer to the indexable object whose size is required

Returns:

The size of an object in bytes excluding the header

Throws:

CorruptDataException

getHeaderSize

public abstract UDATA getHeaderSize(com.ibm.j9ddr.vm29.pointer.generated.J9ObjectPointer object)
                             throws CorruptDataException

Returns the size of an object header, in bytes.

Parameters:

object - Pointer to an object

Returns:

The size of an object header, in bytes.

Throws:

CorruptDataException

getElementAddress

public abstract VoidPointer getElementAddress(com.ibm.j9ddr.vm29.pointer.generated.J9IndexableObjectPointer indexableObjectPointer,
 int elementIndex,
 int elementSize)
                                       throws CorruptDataException

Returns the address of the element at elementIndex logical offset into indexableObjectPointer, assuming that each element is dataSize bytes.

Parameters:

indexableObjectPointer - The array from which we should look-up the address

elementIndex - The logical index number of the element within the array

elementSize - The size, in bytes, of a single element of the array

Returns:

A pointer to the element

Throws:

CorruptDataException

isInlineContiguousArraylet

public boolean isInlineContiguousArraylet(com.ibm.j9ddr.vm29.pointer.generated.J9IndexableObjectPointer arrayPtr)
                                   throws CorruptDataException

Parameters:

arrayPtr - array object we are checking for isInlineContiguousArraylet

Throws:

CorruptDataException - If there's a problem accessing the layout of the indexable object