"

 COPYRIGHT (c) 1996-2015 by Claus Gittinger

 New code and modifications done at SWING Research Group [1]:

 COPYRIGHT (c) 2010-2015 by Jan Vrany, Jan Kurs and Marcel Hlopko

                            SWING Research Group, Czech Technical University in Prague

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

 [1] Code written at SWING Research Group contains a signature

     of one of the above copright owners. For exact set of such code,

     see the differences between this version and version stx:libjava

     as of 1.9.2010

"

"{ Package: 'stx:libjava' }"

"{ NameSpace: Smalltalk }"

Object subclass:#JavaMonitor

	instanceVariableNames:'owningProcess monitorSema count waitingSema waitEnabled

		ownerPrintString'

	classVariableNames:'instVarAccess'

	poolDictionaries:''

	category:'Languages-Java-Support'

!

!JavaMonitor class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1996-2015 by Claus Gittinger

 New code and modifications done at SWING Research Group [1]:

 COPYRIGHT (c) 2010-2015 by Jan Vrany, Jan Kurs and Marcel Hlopko

                            SWING Research Group, Czech Technical University in Prague

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

 [1] Code written at SWING Research Group contains a signature

     of one of the above copright owners. For exact set of such code,

     see the differences between this version and version stx:libjava

     as of 1.9.2010

"

! !

!JavaMonitor class methodsFor:'initialization'!

initialize

    instVarAccess := RecursionLock forMutualExclusion.

    "Created: / 29-11-2011 / 11:23:56 / Marcel Hlopko <hlopkmar@fel.cvut.cz>"

    "Modified (format): / 09-01-2013 / 16:10:10 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!JavaMonitor class methodsFor:'instance creation'!

for: owningObject

    ^ self basicNew initializeFor: owningObject.

    "Created: / 30-11-2011 / 20:39:55 / Marcel Hlopko <hlopkmar@fel.cvut.cz>"

!

for: owningObject thread: threadOrNil nestedLockCount: count

    ^ self basicNew initializeFor: owningObject thread: threadOrNil nestedLockCount: count

    "Created: / 26-08-2012 / 17:01:43 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!JavaMonitor methodsFor:'accessing'!

count

    ^ count

!

processesEntered

    "Return a alist of processes that entered the monitor. For testing / debugging purposes only!!"

    ^ owningProcess isNil 

        ifTrue:[ #() ]

        ifFalse:[ (Array with: owningProcess) , monitorSema waitingProcesses ]

    "Created: / 20-11-2011 / 13:22:15 / Marcel Hlopko <hlopkmar@fel.cvut.cz>"

    "Modified (format): / 03-06-2017 / 23:10:31 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!JavaMonitor methodsFor:'atomic'!

disableWait

    JavaVM monitorTrace ifTrue:[

        Logger log: ('Waiting is disabled on monitor for %1' bindWith: ownerPrintString) severity:Logger severityDEBUG facility:#JVM.

    ].

    "/ critical region not needed here

    "/ self instVarAccessCritical: [ waitEnabled := false ].

    waitEnabled := false.

    "Created: / 30-11-2011 / 20:34:40 / Marcel Hlopko <hlopkmar@fel.cvut.cz>"

    "Modified: / 02-03-2015 / 14:06:51 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

enableWait

    "/ critical region not needed here

    "/ self instVarAccessCritical: [waitEnabled := true].

    waitEnabled := true

    "Created: / 30-11-2011 / 20:34:31 / Marcel Hlopko <hlopkmar@fel.cvut.cz>"

    "Modified (format): / 11-10-2013 / 11:17:58 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

instVarAccessCritical: aBlock

    ^ instVarAccess critical: aBlock.

    "Created: / 03-06-2017 / 22:09:24 / Jan Vrany <jan.vrany@fit.cvut.cz>"

    "Modified: / 03-06-2017 / 23:15:27 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

waitEnabled

    "/ critical region not needed here

    "/ self instVarAccessCritical: [ ^ waitEnabled].

    ^ waitEnabled.

    "Created: / 30-11-2011 / 20:34:56 / Marcel Hlopko <hlopkmar@fel.cvut.cz>"

! !

!JavaMonitor methodsFor:'initialization'!

initializeFor: owningObject

    self initializeFor: owningObject thread: 0 nestedLockCount: 0.

    "Created: / 30-11-2011 / 20:39:31 / Marcel Hlopko <hlopkmar@fel.cvut.cz>"

    "Modified: / 26-08-2012 / 17:25:55 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

initializeFor:owningObject thread:threadId nestedLockCount:cnt 

"/    self assert: (owningObject isJavaObject or:[owningObject isJavaClass]).

    waitEnabled := true.

    waitingSema := Semaphore new:0.

    ownerPrintString := owningObject class name , '@' , owningObject identityHash printString.

    "/Not locked...    

    threadId == 0 ifTrue:[

        monitorSema := Semaphore new:1.

        count := 0.

        ^self.

    ] ifFalse: [

        "threadId is not zero (zero is threadId of scheduler process, which will never try to acquire the monitor)"

        "so it means it is possible that the thin lock is already locked for other thread, we must be careful " 

        owningProcess := ObjectMemory processesKnownInVM detect:[:p|p id == threadId] ifNone:[nil].

        self assert: owningProcess notNil.

        cnt timesRepeat:[

"/            JavaVM enteredMonitorsOf:  owningProcess add: owningObject.

"/            JavaVM acquiredMonitorsOf: owningProcess add: owningObject.

        ].

        monitorSema := Semaphore new: 0.

        count := cnt.

    ].

    "Created: / 26-08-2012 / 17:02:29 / Jan Vrany <jan.vrany@fit.cvut.cz>"

    "Modified: / 03-06-2017 / 23:10:47 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!JavaMonitor methodsFor:'public'!

acquire

    thisProcess := Processor activeProcess.

    ].

    "Created: / 20-11-2011 / 13:21:46 / Marcel Hlopko <hlopkmar@fel.cvut.cz>"

!

enter

    self acquire.

    "Created: / 20-11-2011 / 13:21:42 / Marcel Hlopko <hlopkmar@fel.cvut.cz>"

    "Modified: / 03-06-2017 / 23:11:03 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

exit

    | thisProcess |

    "JV@2017-06-03: Question: Is it legal (i.e., is the good reason to) call #exit 

     on a monitor by a process that does not own it? Shouldn't we rather throw an 

     error"

    thisProcess := Processor activeProcess.

    (self isOwnedBy: thisProcess) ifTrue: [ self release. ].

    "Created: / 20-11-2011 / 13:21:54 / Marcel Hlopko <hlopkmar@fel.cvut.cz>"

    "Modified (format): / 03-06-2017 / 23:13:39 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

notify

    "wakeup one waiting process"

    | thisProcess |

    thisProcess := Processor activeProcess.

    JavaVM monitorTrace ifTrue:[

        Logger 

            log: ('%1: notifying %2 processes' bindWith: thisProcess printString

                    with: waitingSema waitingProcesses size)

            severity: Logger severityDEBUG

            facility: #JVM.

    ].

    waitingSema signal.

    Processor yield.

    "Created: / 22-11-2011 / 12:14:23 / Marcel Hlopko <hlopkmar@fel.cvut.cz>"

!

notifyAll

    "wakeup one waiting process"

    | thisProcess |

    thisProcess := Processor activeProcess.

    JavaVM monitorTrace ifTrue:[

        Logger 

            log: ('%1: notifying all %2 processes' bindWith: thisProcess printString

                    with: waitingSema waitingProcesses size)

            severity: Logger severityDEBUG

            facility: #JVM.

    ].

    waitingSema signalForAll.

    Processor yield.

    "Created: / 22-11-2011 / 12:14:36 / Marcel Hlopko <hlopkmar@fel.cvut.cz>"

!

release

    self assert: (self isOwnedBy: owningProcess).

        count := 0.

        monitorSema signal.

    "Created: / 20-11-2011 / 13:21:52 / Marcel Hlopko <hlopkmar@fel.cvut.cz>"

!

wait

    "make owning process to go to wait"

    self waitForMilliseconds: nil.

    "Created: / 22-11-2011 / 11:57:56 / Marcel Hlopko <hlopkmar@fel.cvut.cz>"

!

waitForMilliseconds: timeOut 

    "make owning process to go to wait, but not longer than timeout"

    | thisProcess countBeforeWait |

    thisProcess := Processor activeProcess.

    self waitEnabled ifFalse: [

        JavaVM monitorTrace ifTrue:[

            Logger 

                log: ('%1 wanted to go to sleep, but it cant, this monitor is for %2 which is already dead' 

                        bindWith: thisProcess printString

                        with: ownerPrintString)

                severity: Logger severityDEBUG

                facility: #JVM.

        ].

        ^ self.

    ].

    JavaVM monitorTrace ifTrue:[

        Logger 

            log: ('%1 is going to wait on %3 for timeout: %2' 

                    bindWith: thisProcess printString

                    with: timeOut

                    with: ownerPrintString printString)

            severity: #debug

            facility: #JVM.

    ].

     "JV@2011-11-25: zero timeout means wait without timeout!!!!!!"

    timeOut == 0 ifTrue: [ waitingSema wait ] ifFalse: [

        waitingSema waitWithTimeoutMs: timeOut

    ].

    JavaVM monitorTrace ifTrue:[ 

        Logger 

            log: ('%1 has been notified and is trying to acquire monitor for %2 which is owned by %3' 

                    bindWith: thisProcess printString with: ownerPrintString printString with: owningProcess printString)

            severity: #debug

            facility: #JVM.

    ].

    self acquire.

    "Created: / 22-11-2011 / 12:52:45 / Marcel Hlopko <hlopkmar@fel.cvut.cz>"

    "Modified: / 01-12-2011 / 10:57:52 / Marcel Hlopko <hlopkmar@fel.cvut.cz>"

! !

!JavaMonitor methodsFor:'queries'!

isAcquired

    ^ self instVarAccessCritical: [ owningProcess notNil ].

    "Created: / 20-11-2011 / 13:22:26 / Marcel Hlopko <hlopkmar@fel.cvut.cz>"

!

isOwnedBy: aProcess 

    ^ self instVarAccessCritical: [ owningProcess == aProcess ].

    "Created: / 20-11-2011 / 13:23:14 / Marcel Hlopko <hlopkmar@fel.cvut.cz>"

! !

!JavaMonitor class methodsFor:'documentation'!

version_CVS

    ^ '$Header$'

!

version_HG

    ^ '$Changeset: <not expanded> $'

!

version_SVN

    ^ '$Id$'

! !

JavaMonitor initialize!