Module openj9.dtfj

Package com.ibm.dtfj.java.j9

Class JavaObject

java.lang.Object

com.ibm.dtfj.java.j9.JavaObject

All Implemented Interfaces:

JavaObject

public class JavaObject
extends Object
implements JavaObject

Field Summary

Fields

Modifier and Type	Field	Description
protected static final String	ARRAY_PREFIX_SIGNATURE
protected static final String	BOOLEAN_SIGNATURE
protected static final String	BYTE_SIGNATURE
protected static final String	CHAR_SIGNATURE
protected static final String	DOUBLE_SIGNATURE
protected static final String	FLOAT_SIGNATURE
protected static final String	INTEGER_SIGNATURE
protected static final String	LONG_SIGNATURE
protected static final String	OBJECT_PREFIX_SIGNATURE
protected static final String	SHORT_SIGNATURE

Method Summary

Modifier and Type	Method	Description
void	arraycopy(int srcStart, Object dst, int dstStart, int length)	Copies data from the image array into a local Java array.
static JavaObject	createJavaObject(JavaRuntime vm, ImagePointer address)	Deprecated. Use JavaRuntime.getObjectAtAddress(ImagePointer) instead
static JavaObject	createJavaObject(JavaRuntime vm, ImagePointer address, JavaHeap containingHeap, JavaHeapRegion containingRegion)	Deprecated. Use invalid reference JavaRuntime#getObjectInHeapRegion(ImagePointer,JavaHeap,JavaHeapRegion) instead
boolean	equals(Object obj)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
int	getArraySize()	Get the number of elements in this array.
JavaClass	getAssociatedClass()
JavaClassLoader	getAssociatedClassLoader()
JavaMonitor	getAssociatedMonitor()
JavaThread	getAssociatedThread()
ImagePointer	getFObjectAtOffset(int offset)
int	getFObjectSize()	A method required for the JavaArrayClass so it can ask the instance it is trying to size how big reference fields are in its heap
long	getHashcode()	Fetch the basic hash code for the object.
JavaHeap	getHeap()	Gets the heap where this object is located.
ImagePointer	getID()	The ID of an object is a unique address is memory which identifies the object.
JavaClass	getJavaClass()	Get the JavaClass instance which represents the class of this object.
long	getPersistentHashcode()	Fetch the basic hash code of the object in the image.
Iterator	getReferences()	Get the set of references from this object.
Iterator	getSections()	An object is represented in the Java runtime by one or more regions of memory.
long	getSize()	Get the number of bytes of memory occupied by this object on the heap.
int	hashCode()	Answers an integer hash code for the receiver.
boolean	isArray()	Is this object an array?
boolean	isArraylet()
boolean	isClass()
boolean	isClassLoader()
boolean	isMonitor()
boolean	isThread()
void	setAssociatedClass(JavaClass associatedClass)
void	setAssociatedClassLoader(JavaClassLoader associatedClassLoader)
void	setAssociatedMonitor(JavaMonitor associatedMonitor)
void	setAssociatedThread(JavaThread associatedThread)

Methods declared in class java.lang.Object

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

Field Details

BOOLEAN_SIGNATURE

protected static final String BOOLEAN_SIGNATURE

See Also:

• Constant Field Values

BYTE_SIGNATURE

protected static final String BYTE_SIGNATURE

See Also:

• Constant Field Values

CHAR_SIGNATURE

protected static final String CHAR_SIGNATURE

See Also:

• Constant Field Values

SHORT_SIGNATURE

protected static final String SHORT_SIGNATURE

See Also:

• Constant Field Values

INTEGER_SIGNATURE

protected static final String INTEGER_SIGNATURE

See Also:

• Constant Field Values

LONG_SIGNATURE

protected static final String LONG_SIGNATURE

See Also:

• Constant Field Values

FLOAT_SIGNATURE

protected static final String FLOAT_SIGNATURE

See Also:

• Constant Field Values

DOUBLE_SIGNATURE

protected static final String DOUBLE_SIGNATURE

See Also:

• Constant Field Values

ARRAY_PREFIX_SIGNATURE

protected static final String ARRAY_PREFIX_SIGNATURE

See Also:

• Constant Field Values

OBJECT_PREFIX_SIGNATURE

protected static final String OBJECT_PREFIX_SIGNATURE

See Also:

• Constant Field Values

Method Details

createJavaObject

@Deprecated
public static JavaObject createJavaObject(JavaRuntime vm,
 ImagePointer address)
                                   throws CorruptDataException

Deprecated.

Use JavaRuntime.getObjectAtAddress(ImagePointer) instead

Throws:

CorruptDataException

createJavaObject

@Deprecated
public static JavaObject createJavaObject(JavaRuntime vm,
 ImagePointer address,
 JavaHeap containingHeap,
 JavaHeapRegion containingRegion)
                                   throws CorruptDataException

Deprecated.

Use

invalid reference

JavaRuntime#getObjectInHeapRegion(ImagePointer,JavaHeap,JavaHeapRegion)

instead

Throws:

CorruptDataException

getJavaClass

public JavaClass getJavaClass()
                       throws CorruptDataException

Description copied from interface: JavaObject

Get the JavaClass instance which represents the class of this object.

Specified by:

getJavaClass in interface JavaObject

Returns:

the JavaClass instance which represents the class of this object

Throws:

CorruptDataException

isArray

public boolean isArray()
                throws CorruptDataException

Description copied from interface: JavaObject

Is this object an array?

Specified by:

isArray in interface JavaObject

Returns:

true if the receiver represents an instance of an array, or false otherwise

Throws:

CorruptDataException

getArraySize

public int getArraySize()
                 throws CorruptDataException

Description copied from interface: JavaObject

Get the number of elements in this array.

Specified by:

getArraySize in interface JavaObject

Returns:

the number of elements in this array

Throws:

CorruptDataException

arraycopy

public void arraycopy(int srcStart,
 Object dst,
 int dstStart,
 int length)
               throws CorruptDataException,
MemoryAccessException

Description copied from interface: JavaObject

Copies data from the image array into a local Java array. The dst object must be an array of the appropriate type -- a base type array for base types, or a JavaObject array for reference arrays.

Specified by:

arraycopy in interface JavaObject

Parameters:

srcStart - index in the receiver to start copying from

dst - the destination array

dstStart - index in the destination array to start copying into

length - the number of elements to be copied

Throws:

CorruptDataException

MemoryAccessException

getSize

public long getSize()
             throws CorruptDataException

Description copied from interface: JavaObject

Get the number of bytes of memory occupied by this object on the heap. The memory may not necessarily be contiguous.

Specified by:

getSize in interface JavaObject

Throws:

CorruptDataException

getHashcode

public long getHashcode()
                 throws DataUnavailable,
CorruptDataException

Description copied from interface: JavaObject

Fetch the basic hash code for the object. This is the hash code which would be returned if a Java thread had requested it. Typically the hash code is based on the address of an object, and may change if the object is moved by a garbage collection cycle.

Specified by:

getHashcode in interface JavaObject

Returns:

the basic hash code of the object in the image

Throws:

DataUnavailable - if the hash code cannot be determined

CorruptDataException

See Also:

• JavaObject.getPersistentHashcode()

getPersistentHashcode

public long getPersistentHashcode()
                           throws DataUnavailable,
CorruptDataException

Description copied from interface: JavaObject

Fetch the basic hash code of the object in the image. This hash code is guaranteed to be persistent between multiple snapshots of the same Image. If the hash code cannot be determined, or if the hash code for this object could change between snapshots, an exception is thrown.

If the VM uses a 'hasBeenHashed' bit, the value of this bit can be inferred by calling getPersistentHashcode(). If the persistent hash code is not available, then the 'hasBeenHashed' bit has not been set, and the hash of the object could change if the object moves between snapshots

Specified by:

getPersistentHashcode in interface JavaObject

Returns:

the basic hash code of the object in the image

Throws:

DataUnavailable - if a hash code cannot be determined, or if the hash code could change between successive snapshots

CorruptDataException

See Also:

• JavaObject.getHashcode()

getID

public ImagePointer getID()

Description copied from interface: JavaObject

The ID of an object is a unique address is memory which identifies the object. The data at this memory is implementation defined. The object may be non-contiguous. Portions of the object may appear below or above this address.

Specified by:

getID in interface JavaObject

Returns:

the runtime-wide unique identifier for the object

getSections

public Iterator getSections()

Description copied from interface: JavaObject

An object is represented in the Java runtime by one or more regions of memory. These include the object's header and the data in the object. In certain allocation strategies, an object's header and data may be allocated contiguously. In this case, this method may return an iterator for a single section. In other schemes, the header may be separate from the data or the data may be broken up into multiple regions. Additionally, this function does not guarantee that the memory used by this object is not also shared by one or more other objects. Callers should not make any assumptions about the contents of the memory.

Specified by:

getSections in interface JavaObject

Returns:

a collection of sections that make up this object

See Also:

• ImageSection
• CorruptData

equals

public boolean equals(Object obj)

Description copied from interface: JavaObject

Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison. The implementation in Object answers true only if the argument is the exact same object as the receiver (==).

Specified by:

equals in interface JavaObject

Overrides:

equals in class Object

Parameters:

obj - Object the object to compare with this object.

Returns:

boolean true if the object is the same as this object false if it is different from this object.

See Also:

• Object.hashCode()

hashCode

public int hashCode()

Description copied from interface: JavaObject

Answers an integer hash code for the receiver. Any two objects which answer true when passed to .equals must answer the same value for this method.

Specified by:

hashCode in interface JavaObject

Overrides:

hashCode in class Object

Returns:

the receiver's hash.

See Also:

• Object.equals(java.lang.Object)

isArraylet

public boolean isArraylet()

getFObjectAtOffset

public ImagePointer getFObjectAtOffset(int offset)
                                throws MemoryAccessException,
CorruptDataException

Throws:

MemoryAccessException

CorruptDataException

getFObjectSize

public int getFObjectSize()

A method required for the JavaArrayClass so it can ask the instance it is trying to size how big reference fields are in its heap

Returns:

The size of fj9object_t in the heap containing this instance

getReferences

public Iterator getReferences()

Description copied from interface: JavaObject

Get the set of references from this object. Corrupt references will be returned as CorruptData objects by the Iterator.

Specified by:

getReferences in interface JavaObject

Returns:

an iterator of JavaReference and CorruptData objects

See Also:

• JavaReference
• CorruptData

isClass

public boolean isClass()

isMonitor

public boolean isMonitor()

isThread

public boolean isThread()

isClassLoader

public boolean isClassLoader()

getHeap

public JavaHeap getHeap()
                 throws DataUnavailable

Description copied from interface: JavaObject

Gets the heap where this object is located.

Specified by:

getHeap in interface JavaObject

Returns:

the JavaHeap instance representing the heap where this object is stored in memory

Throws:

DataUnavailable - if the heap information for this object is not available

See Also:

• JavaHeap

getAssociatedClass

public JavaClass getAssociatedClass()

Returns:

the associatedClass

setAssociatedClass

public void setAssociatedClass(JavaClass associatedClass)

Parameters:

associatedClass - the associatedClass to set

getAssociatedMonitor

public JavaMonitor getAssociatedMonitor()

Returns:

the associatedMonitor

setAssociatedMonitor

public void setAssociatedMonitor(JavaMonitor associatedMonitor)

Parameters:

associatedMonitor - the associatedMonitor to set

getAssociatedThread

public JavaThread getAssociatedThread()

Returns:

the associatedThread

setAssociatedThread

public void setAssociatedThread(JavaThread associatedThread)

Parameters:

associatedThread - the associatedThread to set

getAssociatedClassLoader

public JavaClassLoader getAssociatedClassLoader()

Returns:

the associatedClassLoader

setAssociatedClassLoader

public void setAssociatedClassLoader(JavaClassLoader associatedClassLoader)

Parameters:

associatedClassLoader - the associatedClassLoader to set