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com.tangosol.net
Class GuardSupport

java.lang.Object
com.tangosol.util.Base
com.tangosol.net.GuardSupport

public class GuardSupport

extends Base

A concrete implementation of Guardian/Guardable interactions. GuardSupport is used by a Guardian to manage its responsibilities.

Since:

Coherence 3.5

Author:

rhl

Nested Class Summary

protected class

GuardSupport.Context Base implementation for GuardContext's used by GuardSupport.

Field Summary

protected static long	GUARDIAN_EARLY_THRESHOLD The threshold before which than which a guardian considers itself early in checking its guardables.
protected static long	GUARDIAN_LATE_THRESHOLD The threshold past which a guardian considers itself late in checking its guardables.
protected static long	GUARDIAN_LOG_INTERVAL The minimum interval at which the Guardian should log thread dumps.
static long	GUARDIAN_MAX_CHECK_INTERVAL The maximum interval at which the Guardian thread should call check() to verify its guardables.
protected GuardSupport.Context[]	m_aGuardContext Array of GuardContexts for the registered Guardables.
protected int	m_cGuardable The number of registered Guardables.
protected Guardian	m_guardian The Guardian that is managing this GuardSupport.
protected long	m_ldtNextCheck The next time at which the Guardables should be checked.
protected static java.lang.ThreadLocal	m_tlContext ThreadLocal containing the GuardContext associated with the current thread.
protected static java.util.concurrent.atomic.AtomicLong	s_atomicLogTime Atomic counter containing the last log time stamp.
protected static java.lang.management.ThreadMXBean	s_beanThread MXBean for the thread system

Constructor Summary

GuardSupport(Guardian guardian)
Construct a GuardSupport for the specified Guardian.

Method Summary

Guardian.GuardContext	add(Guardable guardable, long cMillis, float flPctRecover) Add the specified guardable to the set of Guardables managed by this manager, subject to the specified service parameters.
long	check() Check the registered Guardable objects for timeout, taking appropriate action and calculate the timestamp when the next check should be performed.
protected static java.util.Set	collectDeadlockedIds() Collect the deadlocked thread ids.
static void	collectLockedSyncs(java.lang.management.ThreadInfo infoThread, java.lang.StringBuilder sbTrace) Collect locked synchronizers for a given thread.
static void	collectStackTrace(java.lang.management.ThreadInfo infoThread, java.lang.StringBuilder sbTrace) Collect stack trace for a given thread.
static void	collectThreadHeader(java.lang.management.ThreadInfo infoThread, java.lang.StringBuilder sbTrace, boolean fDeadlocked) Collect the header information for a given thread.
int	getGuardableCount() Return the number of Guardables that are registered with this GuardSupport.
protected GuardSupport.Context[]	getGuardContexts() Return the array of GuardContext objects for the Guardables managed by this GuardSupport.
protected Guardian	getGuardian() Return the Guardian that manages this GuardSupport.
long	getNextCheckTime() Return the next time at which the Guardables should be checked.
static Guardian.GuardContext	getThreadContext() Obtain the GuardContext associated with the current thread.
static java.lang.String	getThreadDump() Get the full thread dump.
static void	heartbeat() Issue a heartbeat on the GuardContext associated with the current thread.
static void	heartbeat(long cMillis) Issue a heartbeat of the specified duration on the GuardContext associated with the current thread.
protected GuardSupport.Context	instantiateContext(Guardable guardable, long cMillis, float flPctRecover)
static void	logStackTraces() Collect stack traces and synchronization information for all running threads and write them to the error log.
void	release() Release the Guardables managed by this GuardSupport.
void	remove(Guardable guardable) Remove the specified Guardable from the set of Guardables managed by this manager.
protected void	setGuardableCount(int cGuardable) Set the number of Guardables that are registered with this GuardSupport.
protected void	setGuardContexts(GuardSupport.Context[] aGuardContext) Set the array of GuardContext objects for the Guardables that are managed by this GuardSupport.
protected void	setNextCheckTime(long ldtNextCheck) Set the next time at which the Guardables should be checked.
static void	setThreadContext(Guardian.GuardContext context) Associate the specified GuardContext with the current thread.

Field Detail

GUARDIAN_MAX_CHECK_INTERVAL

public static final long GUARDIAN_MAX_CHECK_INTERVAL

The maximum interval at which the Guardian thread should call check() to verify its guardables.

See Also:

Constant Field Values

GUARDIAN_LATE_THRESHOLD

protected static final long GUARDIAN_LATE_THRESHOLD

The threshold past which a guardian considers itself late in checking its guardables.

See Also:

Constant Field Values

GUARDIAN_EARLY_THRESHOLD

protected static final long GUARDIAN_EARLY_THRESHOLD

The threshold before which than which a guardian considers itself early in checking its guardables.

See Also:

Constant Field Values

GUARDIAN_LOG_INTERVAL

protected static final long GUARDIAN_LOG_INTERVAL

The minimum interval at which the Guardian should log thread dumps.

See Also:

Constant Field Values

m_aGuardContext

protected GuardSupport.Context[] m_aGuardContext

Array of GuardContexts for the registered Guardables. May contain nulls.

m_cGuardable

protected int m_cGuardable

The number of registered Guardables.

m_guardian

protected Guardian m_guardian

The Guardian that is managing this GuardSupport.

m_ldtNextCheck

protected long m_ldtNextCheck

The next time at which the Guardables should be checked.

m_tlContext

protected static java.lang.ThreadLocal m_tlContext

ThreadLocal containing the GuardContext associated with the current thread.

s_atomicLogTime

protected static java.util.concurrent.atomic.AtomicLong s_atomicLogTime

Atomic counter containing the last log time stamp.

s_beanThread

protected static java.lang.management.ThreadMXBean s_beanThread

MXBean for the thread system

Constructor Detail

GuardSupport

public GuardSupport(Guardian guardian)

Construct a GuardSupport for the specified Guardian.

Parameters:

guardian - the guardian managing this GuardSupport

Method Detail

getGuardContexts

protected GuardSupport.Context[] getGuardContexts()

Return the array of GuardContext objects for the Guardables managed by this GuardSupport.

Returns:

the array of managed GuardContext objects

setGuardContexts

protected void setGuardContexts(GuardSupport.Context[] aGuardContext)

Set the array of GuardContext objects for the Guardables that are managed by this GuardSupport.

Parameters:

aGuardContext - the array of managed GuardContext objects

getGuardian

protected Guardian getGuardian()

Return the Guardian that manages this GuardSupport.

Returns:

the Guardian that manages this GuardSupport

getNextCheckTime

public long getNextCheckTime()

Return the next time at which the Guardables should be checked.

Returns:

the next time at which the Guardables should be checked

setNextCheckTime

protected void setNextCheckTime(long ldtNextCheck)

Set the next time at which the Guardables should be checked.

Parameters:

ldtNextCheck - the next time at which the Guardables should be checked

add

public Guardian.GuardContext add(Guardable guardable,
                                 long cMillis,
                                 float flPctRecover)

Add the specified guardable to the set of Guardables managed by this manager, subject to the specified service parameters. If the specified guardable is already guarded by this manager, adjust the service parameters.

Parameters:

guardable - the Guardable object to be managed

cMillis - the timeout for the specified Guardable

flPctRecover - the percentage of the timeout after which to attempt recovery of the Guardable; 0 < flPctRecover &lteq; 1.0

Returns:

the GuardContext for the specified Guardable

remove

public void remove(Guardable guardable)

Remove the specified Guardable from the set of Guardables managed by this manager.

Parameters:

guardable - the guardable to remove

getGuardableCount

public int getGuardableCount()

Return the number of Guardables that are registered with this GuardSupport.

Returns:

the number of registered Guardable objects

setGuardableCount

protected void setGuardableCount(int cGuardable)

Set the number of Guardables that are registered with this GuardSupport.

Parameters:

cGuardable - the number of registered Guardable objects

check

public long check()

Check the registered Guardable objects for timeout, taking appropriate action and calculate the timestamp when the next check should be performed. The next check time can later be retrieved by the getNextCheckTime() method.

Returns:

the number of milliseconds past the time when the guardables should have been checked, or 0 if the check was performed on time

release

public void release()

Release the Guardables managed by this GuardSupport. Releasing a Guardable causes it to no longer be guarded.

instantiateContext

protected GuardSupport.Context instantiateContext(Guardable guardable,
                                                  long cMillis,
                                                  float flPctRecover)

Parameters:

guardable - the Guardable object to be managed

cMillis - the timeout for the specified Guardable

flPctRecover - the percentage of the timeout after which to attempt recovery of the Guardable; 0 < flPctRecover &lteq; 1.0

Returns:

a Context for the specified guardable and SLA parameters

getThreadContext

public static Guardian.GuardContext getThreadContext()

Obtain the GuardContext associated with the current thread.

Returns:

the GuardContext or null if it has not been set

setThreadContext

public static void setThreadContext(Guardian.GuardContext context)

Associate the specified GuardContext with the current thread.

Parameters:

context - the GuardContext to associate with the current thread

heartbeat

public static void heartbeat()

Issue a heartbeat on the GuardContext associated with the current thread.

heartbeat

public static void heartbeat(long cMillis)

Issue a heartbeat of the specified duration on the GuardContext associated with the current thread.

Parameters:

cMillis - the number of milliseconds to heartbeat for

logStackTraces

public static void logStackTraces()

Collect stack traces and synchronization information for all running threads and write them to the error log.

getThreadDump

public static java.lang.String getThreadDump()

Get the full thread dump.

Returns:

a string containing the thread dump

collectThreadHeader

public static void collectThreadHeader(java.lang.management.ThreadInfo infoThread,
                                       java.lang.StringBuilder sbTrace,
                                       boolean fDeadlocked)

Collect the header information for a given thread.

Parameters:

infoThread - the ThreadInfo that the thread is associated with

sbTrace - the StringBuilder to append the info to

fDeadlocked - true iff the thread is in deadlock

collectLockedSyncs

public static void collectLockedSyncs(java.lang.management.ThreadInfo infoThread,
                                      java.lang.StringBuilder sbTrace)

Collect locked synchronizers for a given thread.

Parameters:

infoThread - the ThreadInfo that the thread is associated with

sbTrace - the StringBuilder to append the info to

collectStackTrace

public static void collectStackTrace(java.lang.management.ThreadInfo infoThread,
                                     java.lang.StringBuilder sbTrace)

Collect stack trace for a given thread.

Parameters:

infoThread - the ThreadInfo that the thread is associated with

sbTrace - the StringBuilder to append the info to

collectDeadlockedIds

protected static java.util.Set collectDeadlockedIds()

Collect the deadlocked thread ids.

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