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java.lang.management
class ThreadInfo
public class ThreadInfo
extends Object
Thread information. ThreadInfo contains the information
about a thread including:
General thread information
- Thread ID.
- Name of the thread.
Execution information
- Thread state.
- The object upon which the thread is blocked due to:
- waiting to enter a synchronization block/method, or
- waiting to be notified in a {@link Object#wait Object.wait} method,
or
- parking due to a {@link java.util.concurrent.locks.LockSupport#park
LockSupport.park} call.
- The ID of the thread that owns the object
that the thread is blocked.
- Stack trace of the thread.
- List of object monitors locked by the thread.
- List of
ownable synchronizers locked by the thread.
- The number of times that the thread has blocked for
synchronization or waited for notification.
- The accumulated elapsed time that the thread has blocked
for synchronization or waited for notification
since {@link ThreadMXBean#setThreadContentionMonitoringEnabled
thread contention monitoring}
was enabled. Some Java virtual machine implementation
may not support this. The
{@link ThreadMXBean#isThreadContentionMonitoringSupported()}
method can be used to determine if a Java virtual machine
supports this.
This thread information class is designed for use in monitoring of
the system, not for synchronization control.
MXBean Mapping
ThreadInfo is mapped to a {@link CompositeData CompositeData}
with attributes as specified in
the {@link #from from} method.
Method Summary |
static ThreadInfo |
Returns a ThreadInfo object represented by the
given CompositeData.
|
long |
Returns the total number of times that
the thread associated with this ThreadInfo
blocked to enter or reenter a monitor.
|
long |
Returns the approximate accumulated elapsed time (in milliseconds)
that the thread associated with this ThreadInfo
has blocked to enter or reenter a monitor
since thread contention monitoring is enabled.
|
MonitorInfo[] |
Returns an array of java.lang.management.MonitorInfo objects, each of which
represents an object monitor currently locked by the thread
associated with this ThreadInfo.
|
LockInfo[] |
Returns an array of java.lang.management.LockInfo objects, each of which
represents an ownable
synchronizer currently locked by the thread associated with
this ThreadInfo.
|
LockInfo |
Returns the LockInfo of an object for which
the thread associated with this ThreadInfo
is blocked waiting.
|
String |
Returns the java.lang.management.LockInfo.toString
of an object for which the thread associated with this
ThreadInfo is blocked waiting.
|
long |
Returns the ID of the thread which owns the object
for which the thread associated with this ThreadInfo
is blocked waiting.
|
String |
Returns the name of the thread which owns the object
for which the thread associated with this ThreadInfo
is blocked waiting.
|
StackTraceElement[] |
Returns the stack trace of the thread
associated with this ThreadInfo.
|
long |
Returns the ID of the thread associated with this ThreadInfo.
|
String |
Returns the name of the thread associated with this ThreadInfo.
|
Thread.State |
Returns the state of the thread associated with this ThreadInfo.
|
long |
Returns the total number of times that
the thread associated with this ThreadInfo
waited for notification.
|
long |
Returns the approximate accumulated elapsed time (in milliseconds)
that the thread associated with this ThreadInfo
has waited for notification
since thread contention monitoring is enabled.
|
boolean |
Tests if the thread associated with this ThreadInfo
is executing native code via the Java Native Interface (JNI).
|
boolean |
Tests if the thread associated with this ThreadInfo
is suspended.
|
String |
Returns a string representation of this thread info.
|
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
from
public static ThreadInfo from(CompositeData cd)
-
Returns a ThreadInfo object represented by the
given CompositeData.
The given CompositeData must contain the following attributes
unless otherwise specified below:
Attribute Name |
Type |
threadId |
java.lang.Long |
threadName |
java.lang.String |
threadState |
java.lang.String |
suspended |
java.lang.Boolean |
inNative |
java.lang.Boolean |
blockedCount |
java.lang.Long |
blockedTime |
java.lang.Long |
waitedCount |
java.lang.Long |
waitedTime |
java.lang.Long |
lockInfo |
javax.management.openmbean.CompositeData
- the mapped type for {@link LockInfo} as specified in the
type mapping rules of
{@linkplain javax.management.MXBean MXBeans}.
If cd does not contain this attribute,
the LockInfo object will be constructed from
the value of the lockName attribute. |
lockName |
java.lang.String |
lockOwnerId |
java.lang.Long |
lockOwnerName |
java.lang.String |
stackTrace |
javax.management.openmbean.CompositeData[]
Each element is a CompositeData representing
StackTraceElement containing the following attributes:
Attribute Name |
Type |
className |
java.lang.String |
methodName |
java.lang.String |
fileName |
java.lang.String |
lineNumber |
java.lang.Integer |
nativeMethod |
java.lang.Boolean |
|
lockedMonitors |
javax.management.openmbean.CompositeData[]
whose element type is the mapped type for
{@link MonitorInfo} as specified in the
{@link MonitorInfo#from Monitor.from} method.
If cd does not contain this attribute,
this attribute will be set to an empty array. |
lockedSynchronizers |
javax.management.openmbean.CompositeData[]
whose element type is the mapped type for
{@link LockInfo} as specified in the
type mapping rules of
{@linkplain javax.management.MXBean MXBeans}.
If cd does not contain this attribute,
this attribute will be set to an empty array. |
- Parameters:
cd
- CompositeData representing a ThreadInfo
- Returns:
- a ThreadInfo object represented
by cd if cd is not null;
null otherwise.
getBlockedCount
public long getBlockedCount()
-
Returns the total number of times that
the thread associated with this ThreadInfo
blocked to enter or reenter a monitor.
I.e. the number of times a thread has been in the
{@link java.lang.Thread.State#BLOCKED BLOCKED} state.
- Returns:
- the total number of times that the thread
entered the BLOCKED state.
getBlockedTime
public long getBlockedTime()
-
Returns the approximate accumulated elapsed time (in milliseconds)
that the thread associated with this ThreadInfo
has blocked to enter or reenter a monitor
since thread contention monitoring is enabled.
I.e. the total accumulated time the thread has been in the
{@link java.lang.Thread.State#BLOCKED BLOCKED} state since thread
contention monitoring was last enabled.
This method returns -1 if thread contention monitoring
is disabled.
The Java virtual machine may measure the time with a high
resolution timer. This statistic is reset when
the thread contention monitoring is reenabled.
- Returns:
- the approximate accumulated elapsed time in milliseconds
that a thread entered the BLOCKED state;
-1 if thread contention monitoring is disabled.
getLockedMonitors
public MonitorInfo[] getLockedMonitors()
-
Returns an array of {@link MonitorInfo} objects, each of which
represents an object monitor currently locked by the thread
associated with this ThreadInfo.
If no locked monitor was requested for this thread info or
no monitor is locked by the thread, this method
will return a zero-length array.
- Returns:
- an array of MonitorInfo objects representing
the object monitors locked by the thread.
getLockedSynchronizers
public LockInfo[] getLockedSynchronizers()
-
Returns an array of {@link LockInfo} objects, each of which
represents an ownable
synchronizer currently locked by the thread associated with
this ThreadInfo. If no locked synchronizer was
requested for this thread info or no synchronizer is locked by
the thread, this method will return a zero-length array.
- Returns:
- an array of LockInfo objects representing
the ownable synchronizers locked by the thread.
getLockInfo
public LockInfo getLockInfo()
-
Returns the LockInfo of an object for which
the thread associated with this ThreadInfo
is blocked waiting.
A thread can be blocked waiting for one of the following:
- an object monitor to be acquired for entering or reentering
a synchronization block/method.
The thread is in the {@link java.lang.Thread.State#BLOCKED BLOCKED}
state waiting to enter the synchronized statement
or method.
- an object monitor to be notified by another thread.
The thread is in the {@link java.lang.Thread.State#WAITING WAITING}
or {@link java.lang.Thread.State#TIMED_WAITING TIMED_WAITING} state
due to a call to the {@link Object#wait Object.wait} method.
- a synchronization object responsible for the thread parking.
The thread is in the {@link java.lang.Thread.State#WAITING WAITING}
or {@link java.lang.Thread.State#TIMED_WAITING TIMED_WAITING} state
due to a call to the
{@link java.util.concurrent.locks.LockSupport#park(Object)
LockSupport.park} method. The synchronization object
is the object returned from
{@link java.util.concurrent.locks.LockSupport#getBlocker
LockSupport.getBlocker} method. Typically it is an
ownable synchronizer
or a {@link java.util.concurrent.locks.Condition Condition}.
This method returns null if the thread is not in any of
the above conditions.
- Returns:
- LockInfo of an object for which the thread
is blocked waiting if any; null otherwise.
getLockName
public String getLockName()
-
Returns the {@link LockInfo#toString string representation}
of an object for which the thread associated with this
ThreadInfo is blocked waiting.
This method is equivalent to calling:
getLockInfo().toString()
This method will return null if this thread is not blocked
waiting for any object or if the object is not owned by any thread.
- Returns:
- the string representation of the object on which
the thread is blocked if any;
null otherwise.
getLockOwnerId
public long getLockOwnerId()
-
Returns the ID of the thread which owns the object
for which the thread associated with this ThreadInfo
is blocked waiting.
This method will return -1 if this thread is not blocked
waiting for any object or if the object is not owned by any thread.
- Returns:
- the thread ID of the owner thread of the object
this thread is blocked on;
-1 if this thread is not blocked
or if the object lis not owned by any thread.
getLockOwnerName
public String getLockOwnerName()
-
Returns the name of the thread which owns the object
for which the thread associated with this ThreadInfo
is blocked waiting.
This method will return null if this thread is not blocked
waiting for any object or if the object is not owned by any thread.
- Returns:
- the name of the thread that owns the object
this thread is blocked on;
null if this thread is not blocked
or if the object is not owned by any thread.
getStackTrace
public StackTraceElement[] getStackTrace()
-
Returns the stack trace of the thread
associated with this ThreadInfo.
If no stack trace was requested for this thread info, this method
will return a zero-length array.
If the returned array is of non-zero length then the first element of
the array represents the top of the stack, which is the most recent
method invocation in the sequence. The last element of the array
represents the bottom of the stack, which is the least recent method
invocation in the sequence.
Some Java virtual machines may, under some circumstances, omit one
or more stack frames from the stack trace. In the extreme case,
a virtual machine that has no stack trace information concerning
the thread associated with this ThreadInfo
is permitted to return a zero-length array from this method.
- Returns:
- an array of StackTraceElement objects of the thread.
getThreadId
public long getThreadId()
-
Returns the ID of the thread associated with this ThreadInfo.
- Returns:
- the ID of the associated thread.
getThreadName
public String getThreadName()
-
Returns the name of the thread associated with this ThreadInfo.
- Returns:
- the name of the associated thread.
getThreadState
public Thread.State getThreadState()
-
Returns the state of the thread associated with this ThreadInfo.
- Returns:
- Thread.State of the associated thread.
getWaitedCount
public long getWaitedCount()
-
Returns the total number of times that
the thread associated with this ThreadInfo
waited for notification.
I.e. the number of times that a thread has been
in the {@link java.lang.Thread.State#WAITING WAITING}
or {@link java.lang.Thread.State#TIMED_WAITING TIMED_WAITING} state.
- Returns:
- the total number of times that the thread
was in the WAITING or TIMED_WAITING state.
getWaitedTime
public long getWaitedTime()
-
Returns the approximate accumulated elapsed time (in milliseconds)
that the thread associated with this ThreadInfo
has waited for notification
since thread contention monitoring is enabled.
I.e. the total accumulated time the thread has been in the
{@link java.lang.Thread.State#WAITING WAITING}
or {@link java.lang.Thread.State#TIMED_WAITING TIMED_WAITING} state
since thread contention monitoring is enabled.
This method returns -1 if thread contention monitoring
is disabled.
The Java virtual machine may measure the time with a high
resolution timer. This statistic is reset when
the thread contention monitoring is reenabled.
- Returns:
- the approximate accumulated elapsed time in milliseconds
that a thread has been in the WAITING or
TIMED_WAITING state;
-1 if thread contention monitoring is disabled.
isInNative
public boolean isInNative()
-
Tests if the thread associated with this ThreadInfo
is executing native code via the Java Native Interface (JNI).
The JNI native code does not include
the virtual machine support code or the compiled native
code generated by the virtual machine.
- Returns:
- true if the thread is executing native code;
false otherwise.
isSuspended
public boolean isSuspended()
-
Tests if the thread associated with this ThreadInfo
is suspended. This method returns true if
{@link Thread#suspend} has been called.
- Returns:
- true if the thread is suspended;
false otherwise.
toString
public String toString()
-
Returns a string representation of this thread info.
The format of this string depends on the implementation.
The returned string will typically include
the {@linkplain #getThreadName thread name},
the {@linkplain #getThreadId thread ID},
its {@linkplain #getThreadState state},
and a {@linkplain #getStackTrace stack trace} if any.
- Overrides:
toString
in class Object
- Returns:
- a string representation of this thread info.
This documentation differs from the official API.
Jadeite adds
extra features to the API including:
variable font sizes,
constructions examples,
placeholders for classes and methods, and auto-generated “See Also” links.
Additionally it
is missing some items found in standard Javadoc documentation, including:
generics type information,
“Deprecated” tags and comments,
“See Also” links,
along with other minor differences.
Please send any questions or feedback to
bam@cs.cmu.edu.
This page displays the
Jadeite version of the documention, which is derived from the offical documentation that contains this copyright notice:
The official Sun™ documentation can be found here at
http://java.sun.com/javase/6/docs/api/.