com.tangosol.util

Class SegmentedConcurrentMap.LockableEntry

java.lang.Object

com.tangosol.util.Base

com.tangosol.util.SegmentedHashMap.Entry

com.tangosol.util.SegmentedConcurrentMap.LockableEntry

All Implemented Interfaces:

Map.Entry

Enclosing class:

SegmentedConcurrentMap

public class SegmentedConcurrentMap.LockableEntry
extends SegmentedHashMap.Entry

LockableEntry is an Entry that supports locking. See ConcurrentMap

Nested Class Summary

Nested classes/interfaces inherited from class com.tangosol.util.Base

Base.LoggingWriter, Base.StackFrame

Field Summary

Fields

Modifier and Type	Field and Description
protected short	m_cContend The number of threads that are waiting to lock this Entry.
protected short	m_cLock The lock count (number of times the "lock()" was called by the locking thread).
protected Object	m_oLockHolder The lock holder object.

Fields inherited from class com.tangosol.util.SegmentedHashMap.Entry

m_eNext, m_nHash, m_oKey, m_oValue

Fields inherited from class com.tangosol.util.Base

LOG_ALWAYS, LOG_DEBUG, LOG_ERR, LOG_INFO, LOG_MAX, LOG_MIN, LOG_QUIET, LOG_WARN, POWER_0, POWER_G, POWER_K, POWER_M, POWER_T, UNIT_D, UNIT_H, UNIT_M, UNIT_MS, UNIT_NS, UNIT_S, UNIT_US

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	LockableEntry(Object oKey, Object oValue, int nHash) Construct a LockableEntry for the given entry.

Method Summary

Modifier and Type	Method and Description
protected boolean	casValueInternal(Object oValueAssume, Object oValue) Set the value of this entry to the specified value iff the current value matches the assumed value.
Object	getLockHolder() Return the holder of this lockable entry, or null if this entry is not locked.
SegmentedConcurrentMap	getSource() Return the SegmentedConcurrentMap containing this Entry.
boolean	isContended() Is there contention (a thread waiting) to lock this Entry?
protected boolean	isLocked() Is this entry Locked?
protected boolean	isSynthetic() Is this Entry synthetic?
protected void	lock(Object oHolder) Lock this entry for the specified lock holder.
protected Object	setValueInternal(Object oValue) Replaces the value corresponding to this entry with the specified value (writes through to the map).
String	toString() Render the map entry as a String.
protected boolean	unlock() Unlock this entry.
protected long	waitForNotify(long cWait) Wait for this LockableEntry to be notified that it has been freed by the previous lock-holder.
protected long	waitForNotify(long cWait, SegmentedConcurrentMap.ContentionObserver observer) Wait for this LockableEntry to be notified that it has been freed by the previous lock-holder.

Methods inherited from class com.tangosol.util.SegmentedHashMap.Entry

equals, getKey, getValue, getValueInternal, hashCode, nextEntry, nextEntry, setNext, setValue

Methods inherited from class com.tangosol.util.Base

azzert, azzert, azzert, azzertFailed, breakLines, breakLines, capitalize, checkNotEmpty, checkNotNull, checkRange, computeSafeWaitTime, decimalValue, dup, dup, ensureBigDecimal, ensureClassLoader, ensureRuntimeException, ensureRuntimeException, equals, equalsDeep, err, err, err, err, err, escape, formatDateTime, getCallerStackFrame, getCommonMonitor, getCommonMonitor, getCommonMonitor, getContextClassLoader, getContextClassLoader, getDeepMessage, getErr, getLastSafeTimeMillis, getLog, getMaxDecDigits, getMaxHexDigits, getOriginalException, getOut, getProcessRandom, getRandom, getRandomBinary, getRandomBinary, getRandomString, getSafeTimeMillis, getStackFrame, getStackFrames, getStackTrace, getStackTrace, getThreadFactory, getTimeZone, getUpTimeMillis, hashCode, hexValue, indentString, indentString, isDecimal, isHex, isLogEcho, isOctal, log, log, log, log, log, makeInteger, makeLong, makeThread, mod, mod, octalValue, out, out, out, out, out, pad, parseBandwidth, parseBandwidth, parseDelimitedString, parseHex, parseHex, parseMemorySize, parseMemorySize, parsePercentage, parseTime, parseTime, parseTimeNanos, parseTimeNanos, printStackTrace, randomize, randomize, randomize, randomize, read, read, read, read, read, read, read, replace, setErr, setLog, setLogEcho, setOut, sleep, toBandwidthString, toBandwidthString, toCharEscape, toCrc, toCrc, toCrc, toCrc, toCrc, toDecString, toDelimitedString, toDelimitedString, toDelimitedString, toDelimitedString, toHex, toHex, toHexDump, toHexEscape, toHexEscape, toHexEscape, toHexEscape, toHexString, toMemorySizeString, toMemorySizeString, toQuotedCharEscape, toQuotedStringEscape, toSqlString, toString, toString, toStringEscape, toUnicodeEscape, trace, trace, trace, trace, trace, trace, trace, trace, trace, truncateString, truncateString, wait

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Map.Entry

comparingByKey, comparingByKey, comparingByValue, comparingByValue

Field Detail

m_oLockHolder

protected volatile Object m_oLockHolder

The lock holder object.

m_cLock

protected volatile short m_cLock

The lock count (number of times the "lock()" was called by the locking thread).

m_cContend

protected volatile short m_cContend

The number of threads that are waiting to lock this Entry.

Constructor Detail

LockableEntry

protected LockableEntry(Object oKey,
                        Object oValue,
                        int nHash)

Construct a LockableEntry for the given entry.

Parameters:

oKey - key with which the specified value is to be associated

oValue - value to be associated with the specified key

nHash - the hashCode for the specified key

Method Detail

getLockHolder

public Object getLockHolder()

Return the holder of this lockable entry, or null if this entry is not locked.

Returns:

the lock holder, or null

getSource

public SegmentedConcurrentMap getSource()

Return the SegmentedConcurrentMap containing this Entry.

Returns:

SegmentedConcurrentMap containing this Entry

isContended

public boolean isContended()

Is there contention (a thread waiting) to lock this Entry?

Returns:

true iff another thread is contending for this Entry

setValueInternal

protected Object setValueInternal(Object oValue)

Replaces the value corresponding to this entry with the specified value (writes through to the map). The behavior of this call is undefined if the mapping has already been removed from the map.

Overrides:

setValueInternal in class SegmentedHashMap.Entry

Parameters:

oValue - new value to be stored in this entry

Returns:

old value corresponding to the entry, or NO_VALUE if the Entry was synthetic

isSynthetic

protected boolean isSynthetic()

Is this Entry synthetic?

Overrides:

isSynthetic in class SegmentedHashMap.Entry

Returns:

true iff this Entry is synthetic

waitForNotify

protected long waitForNotify(long cWait,
                             SegmentedConcurrentMap.ContentionObserver observer)

Wait for this LockableEntry to be notified that it has been freed by the previous lock-holder. If the lock is being held by a thread and that thread has died, release the lock.

Ensure the provided SegmentedConcurrentMap.ContentionObserver is called before and after this thread's wait for the lock-holder to release the lock.

Parameters:

cWait - the number of milliseconds to wait for notification to obtain a lock; pass zero to return immediately; pass -1 to block the calling thread until the lock obtained could be

observer - a ContentionObserver, or null, to be invoked both before and after waiting for the lock-holder to release the lock

Returns:

updated wait time

waitForNotify

protected long waitForNotify(long cWait)

Wait for this LockableEntry to be notified that it has been freed by the previous lock-holder. If the lock is being held by a thread and that thread has died, release the lock.

Note: caller of this method is expected to hold a synchronization monitor for this LockableEntry object while making this call.

Parameters:

cWait - the number of milliseconds to wait for notification to obtain a lock; pass zero to return immediately; pass -1 to block the calling thread until the lock could be obtained

Returns:

updated wait time

lock

protected void lock(Object oHolder)

Lock this entry for the specified lock holder.

Note: caller of this method is expected to have locked the segment for this Entry object

Parameters:

oHolder - the holder of this lock

unlock

protected boolean unlock()

Unlock this entry.

Note: caller of this method is expected to have locked the segment for this Entry object

Returns:

true iff the Entry is completely unlocked

casValueInternal

protected boolean casValueInternal(Object oValueAssume,
                                   Object oValue)

Set the value of this entry to the specified value iff the current value matches the assumed value.

Parameters:

oValueAssume - the assumed value

oValue - the new value

Returns:

true iff the value changed

toString

public String toString()

Render the map entry as a String.

Overrides:

toString in class SegmentedHashMap.Entry

Returns:

the details about this entry

isLocked

protected boolean isLocked()

Is this entry Locked?

Returns:

true iff this entry is locked