Module openj9.dtfj

Package com.ibm.dtfj.java

Interface JavaThread

All Known Implementing Classes:

DTFJJavaThread, JavaThread, JCJavaThread, PHDCorruptJavaThread, PHDJavaThread

public interface JavaThread

Represents a Java thread.

See Also:

• JavaRuntime.getThreads()

Field Summary

Fields

Modifier and Type	Field	Description
static final int	STATE_ALIVE	The thread is alive
static final int	STATE_BLOCKED_ON_MONITOR_ENTER	The thread is waiting to enter an object monitor
static final int	STATE_IN_NATIVE	The thread is in native code
static final int	STATE_IN_OBJECT_WAIT	The thread is in Object.wait
static final int	STATE_INTERRUPTED	The thread has a pending interrupt
static final int	STATE_PARKED	The thread has been deliberately removed from scheduling
static final int	STATE_RUNNABLE	The thread can be run although may not be actually running
static final int	STATE_SLEEPING	The thread is in the Thread.sleep method
static final int	STATE_SUSPENDED	The thread has been suspended by Thread.suspend
static final int	STATE_TERMINATED	The thread has terminated
static final int	STATE_VENDOR_1	The thread is in a vendor specific state
static final int	STATE_VENDOR_2	The thread is in a vendor specific state
static final int	STATE_VENDOR_3	The thread is in a vendor specific state
static final int	STATE_WAITING	The thread is in a waiting state in native code
static final int	STATE_WAITING_INDEFINITELY	The thread is waiting on a monitor with no timeout value set
static final int	STATE_WAITING_WITH_TIMEOUT	The thread is waiting on a monitor but will timeout at some point

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object obj)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
JavaObject	getBlockingObject()	For threads that are in STATE_BLOCKED_ON_MONITOR_ENTER this method returns the JavaObject who's monitor they are blocked on.
ImageThread	getImageThread()	Represents the joining point between the Java view of execution and the corresponding native view.
ImagePointer	getJNIEnv()	Get the address of the JNIEnv structure which represents this thread instance in JNI.
String	getName()	Return the name of the thread.
JavaObject	getObject()	Fetch the java.lang.Thread associated with this thread.
int	getPriority()	Get the Java priority of the thread.
Iterator	getStackFrames()	Get the set of stack frames.
Iterator	getStackSections()	Get the set of ImageSections which make up the managed stack.
int	getState()	Get the state of the thread when the image was created.
int	hashCode()	Answers an integer hash code for the receiver.

Field Details

STATE_ALIVE

static final int STATE_ALIVE

The thread is alive

See Also:

• Constant Field Values

STATE_TERMINATED

static final int STATE_TERMINATED

The thread has terminated

See Also:

• Constant Field Values

STATE_RUNNABLE

static final int STATE_RUNNABLE

The thread can be run although may not be actually running

See Also:

• Constant Field Values

STATE_WAITING_INDEFINITELY

static final int STATE_WAITING_INDEFINITELY

The thread is waiting on a monitor with no timeout value set

See Also:

• Constant Field Values

STATE_WAITING_WITH_TIMEOUT

static final int STATE_WAITING_WITH_TIMEOUT

The thread is waiting on a monitor but will timeout at some point

See Also:

• Constant Field Values

STATE_SLEEPING

static final int STATE_SLEEPING

The thread is in the Thread.sleep method

See Also:

• Constant Field Values

STATE_WAITING

static final int STATE_WAITING

The thread is in a waiting state in native code

See Also:

• Constant Field Values

STATE_IN_OBJECT_WAIT

static final int STATE_IN_OBJECT_WAIT

The thread is in Object.wait

See Also:

• Constant Field Values

STATE_PARKED

static final int STATE_PARKED

The thread has been deliberately removed from scheduling

See Also:

• Constant Field Values

STATE_BLOCKED_ON_MONITOR_ENTER

static final int STATE_BLOCKED_ON_MONITOR_ENTER

The thread is waiting to enter an object monitor

See Also:

• Constant Field Values

STATE_SUSPENDED

static final int STATE_SUSPENDED

The thread has been suspended by Thread.suspend

See Also:

• Constant Field Values

STATE_INTERRUPTED

static final int STATE_INTERRUPTED

The thread has a pending interrupt

See Also:

• Constant Field Values

STATE_IN_NATIVE

static final int STATE_IN_NATIVE

The thread is in native code

See Also:

• Constant Field Values

STATE_VENDOR_1

static final int STATE_VENDOR_1

The thread is in a vendor specific state

See Also:

• Constant Field Values

STATE_VENDOR_2

static final int STATE_VENDOR_2

The thread is in a vendor specific state

See Also:

• Constant Field Values

STATE_VENDOR_3

static final int STATE_VENDOR_3

The thread is in a vendor specific state

See Also:

• Constant Field Values

Method Details

getJNIEnv

ImagePointer getJNIEnv()
                throws CorruptDataException

Get the address of the JNIEnv structure which represents this thread instance in JNI.

Returns:

the address of the JNIEnv structure which represents this thread instance in JNI

Throws:

CorruptDataException

getPriority

int getPriority()
         throws CorruptDataException

Get the Java priority of the thread.

Returns:

the Java priority of the thread (a number between 1 and 10 inclusive)

Throws:

CorruptDataException

See Also:

• Thread.getPriority()

getObject

JavaObject getObject()
              throws CorruptDataException

Fetch the java.lang.Thread associated with this thread. If the thread is in the process of being attached, this may return null.

Returns:

the a JavaObject representing the java.lang.Thread associated with this thread

Throws:

CorruptDataException

See Also:

• JavaObject
• Thread

getState

int getState()
      throws CorruptDataException

Get the state of the thread when the image was created.

Returns:

the state of the thread when the image was created. The result is a bit vector, and uses the states defined by the JVMTI specification.

Throws:

CorruptDataException

getImageThread

ImageThread getImageThread()
                    throws CorruptDataException,
DataUnavailable

Represents the joining point between the Java view of execution and the corresponding native view. This method is where the mapping from Java into native threading resources is provided.

Returns:

the ImageThread which this ManagedThread is currently bound to.

Throws:

CorruptDataException - If the underlying resource describing the native representation of the thread is damaged

DataUnavailable - If no mapping is provided due to missing or limited underlying resources (this exception added in DTFJ 1.1)

See Also:

• ImageThread

getStackSections

Iterator getStackSections()

Get the set of ImageSections which make up the managed stack.

Returns:

a collection of ImageSections which make up the managed stack.

Some Runtime implementations may also use parts of the ImageThread's stack for ManagesStackFrames

See Also:

• ImageSection
• ImageThread.getStackSections()
• CorruptData

getStackFrames

Iterator getStackFrames()

Get the set of stack frames.

Returns:

an iterator to walk the managed stack frames in order from top-of-stack (that is, the most recent frame) to bottom-of-stack

See Also:

• JavaStackFrame
• CorruptData

getName

String getName()
        throws CorruptDataException

Return the name of the thread. Usually this is derived from the object associated with the thread, but if the name cannot be derived this way (e.g. there is no object associated with the thread) DTFJ will synthesize a name for the thread.

Returns:

the name of the thread

Throws:

CorruptDataException

getBlockingObject

JavaObject getBlockingObject()
                      throws CorruptDataException,
DataUnavailable

For threads that are in STATE_BLOCKED_ON_MONITOR_ENTER this method returns the JavaObject who's monitor they are blocked on. For threads that are in STATE_IN_OBJECT_WAIT this method returns the JavaObject that Object.wait() was called on. For threads that are in STATE_PARKED this method returns the JavaObject that was passed as the "blocker" object to the java.util.concurrent.LockSupport.park() call. It may return null if no blocker object was passed. For threads in any other state this call will return null. The state of the thread can be determined by calling JavaThread.getState()

Returns:

the object this thread is waiting on or null.

Throws:

CorruptDataException

DataUnavailable

Since:

1.6

equals

boolean equals(Object obj)

Description copied from class: java.lang.Object

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 (==).

Overrides:

equals in class Object

Parameters:

obj -

Returns:

True if the given object refers to the same Java Thread in the image

See Also:

• Object.hashCode()

hashCode

int hashCode()

Description copied from class: java.lang.Object

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.

Overrides:

hashCode in class Object

Returns:

the receiver's hash.

See Also:

• Object.equals(java.lang.Object)