public abstract class DistributedLockService extends Object
A named instance of DistributedLockService defines a space for locking arbitrary names across the distributed system defined by a specified distribution manager. Any number of DistributedLockService instances can be created with different service names. For all processes in the distributed system that have created an instance of DistributedLockService with the same name, no more than one thread is permitted to own the lock on a given name in that instance at any point in time. Additionally, a thread can lock the entire service, preventing any other threads in the system from locking the service or any names in the service.
Modifier and Type | Method and Description |
---|---|
abstract void |
becomeLockGrantor()
Specifies this member to become the grantor for this lock service.
|
static void |
becomeLockGrantor(String serviceName)
Specifies that this member should become the grantor for the named locking
service.
|
static DistributedLockService |
create(String serviceName,
DistributedSystem ds)
Create a DistributedLockService with the given serviceName for the
given DistributedSystem.
|
static void |
destroy(String serviceName)
Destroy a previously created DistributedLockService with the given
serviceName . |
abstract void |
freeResources(Object name)
Free internal resources associated with the given
name . |
static DistributedLockService |
getServiceNamed(String serviceName)
Look up and return the DistributedLockService with the given name,
if it has been created in this VM.
|
abstract boolean |
isHeldByCurrentThread(Object name)
Determine whether the current thread owns the lock on the given object.
|
abstract boolean |
isLockGrantor()
Returns true if this member is currently the lock authority responsible
for granting locks for this service.
|
static boolean |
isLockGrantor(String serviceName)
Returns true if this member is the grantor for the named service.
|
abstract boolean |
isLockingSuspendedByCurrentThread()
Determine whether the current thread has suspended locking in this
DistributedLockService.
|
abstract boolean |
lock(Object name,
long waitTimeMillis,
long leaseTimeMillis)
Attempts to acquire a lock named
name . |
abstract boolean |
lockInterruptibly(Object name,
long waitTimeMillis,
long leaseTimeMillis)
Deprecated.
as of GemFire 5.1, use
lock(Object, long, long)
with waitTimeMillis instead |
abstract void |
resumeLocking()
Allow locking to resume in this DistributedLockService instance.
|
abstract boolean |
suspendLocking(long waitTimeMillis)
Suspend granting of locks in this service.
|
abstract boolean |
suspendLockingInterruptibly(long waitTimeMillis)
Deprecated.
as of GemFire 5.1, use
suspendLocking(long)
with waitTimeMillis instead |
abstract void |
unlock(Object name)
Release the lock previously granted for the given
name . |
public static DistributedLockService create(String serviceName, DistributedSystem ds) throws IllegalArgumentException
destroy(java.lang.String)
is called, or ds
is disconnected, at which point any
locks that were held by this instance are released.serviceName
- the name of the DistributedLockService to create.ds
- the DistributedSystem
for the new service instance
to use for distributed lock messaging.IllegalArgumentException
- if serviceName is an illegal name or
this process has already created a DistributedLockService with the given
serviceName
.IllegalStateException
- if this process is in the middle of
disconnecting from the DistributedSystem
public static DistributedLockService getServiceNamed(String serviceName)
serviceName
- the name of the DistributedLockService to look uppublic static void destroy(String serviceName) throws IllegalArgumentException
serviceName
. Any locks currently held in this
DistributedLockService by this process are released. Attempts to
access a destroyed lock service will result in a LockServiceDestroyedException
being thrown.serviceName
- the name of the instance to destroy, previously
supplied in the create(String, DistributedSystem)
invocation.IllegalArgumentException
- if this process hasn't created a
DistributedLockService with the given serviceName
and
dm
.public abstract boolean lock(Object name, long waitTimeMillis, long leaseTimeMillis)
Attempts to acquire a lock named name
. Returns
true
as soon as the lock is acquired. If the lock
is currently held by another thread in this or any other process
in the distributed system, or another thread in the system has locked
the entire service, this method keeps trying to acquire the lock for
up to waitTimeMillis
before giving up and returning
false
. If the lock is acquired, it is held until
unlock(Object name)
is invoked, or until
leaseTimeMillis
milliseconds have passed since the
lock was granted - whichever comes first.
Locks are reentrant. If a thread invokes this method n times
on the same instance, specifying the same name
, without
an intervening release or lease expiration expiration on the lock,
the thread must invoke unlock(name)
the same number of
times before the lock is released (unless the lease expires). When
this method is invoked for a lock that is already acquired, the
lease time will be set to the maximum of the remaining least time
from the previous invocation, or leaseTimeMillis
name
- the name of the lock to acquire in this service. This object
must conform to the general contract of equals(Object)
and
hashCode()
as described in
Object.hashCode()
.waitTimeMillis
- the number of milliseconds to try to acquire
the lock before giving up and returning false. A value of -1 causes
this method to block until the lock is acquired. A value of 0 causes
this method to return false without waiting for the lock if the lock is
held by another member or thread.leaseTimeMillis
- the number of milliseconds to hold the lock after
granting it, before automatically releasing it if it hasn't already
been released by invoking unlock(Object)
. If
leaseTimeMillis
is -1, hold the lock until explicitly
unlocked.waitTimeMillis
passed without acquiring the lock.LockServiceDestroyedException
- if this lock service has been
destroyed@Deprecated public abstract boolean lockInterruptibly(Object name, long waitTimeMillis, long leaseTimeMillis) throws InterruptedException
lock(Object, long, long)
with waitTimeMillis insteadAttempts to acquire a lock named name
. Returns
true
as soon as the lock is acquired. If the lock
is currently held by another thread in this or any other process
in the distributed system, or another thread in the system has locked
the entire service, this method keeps trying to acquire the lock for
up to waitTimeMillis
before giving up and returning
false
. If the lock is acquired, it is held until
unlock(Object name)
is invoked, or until
leaseTimeMillis
milliseconds have passed since the
lock was granted - whichever comes first.
Locks are reentrant. If a thread invokes this method n times
on the same instance, specifying the same name
, without
an intervening release or lease expiration expiration on the lock,
the thread must invoke unlock(name)
the same number of
times before the lock is released (unless the lease expires). When
this method is invoked for a lock that is already acquired, the
lease time will be set to the maximum of the remaining least time
from the previous invocation, or leaseTimeMillis
name
- the name of the lock to acquire in this service. This object
must conform to the general contract of equals(Object)
and
hashCode()
as described in
Object.hashCode()
.waitTimeMillis
- the number of milliseconds to try to acquire
the lock before giving up and returning false. A value of -1 causes
this method to block until the lock is acquired.leaseTimeMillis
- the number of milliseconds to hold the lock after
granting it, before automatically releasing it if it hasn't already
been released by invoking unlock(Object)
. If
leaseTimeMillis
is -1, hold the lock until explicitly
unlocked.waitTimeMillis
passed without acquiring the lock.InterruptedException
- if the thread is interrupted before
or during this method.LockServiceDestroyedException
- if this lock service has been
destroyedpublic abstract void unlock(Object name) throws LeaseExpiredException
name
.name
- the object to unlock in this service.LockNotHeldException
- if the current thread is not the
owner of this lockLeaseExpiredException
- if the current thread was the owner
of this lock, but it's lease has expired.LockServiceDestroyedException
- if the service has been destroyedpublic abstract boolean isHeldByCurrentThread(Object name)
name
.LockServiceDestroyedException
- if this service has been destroyed@Deprecated public abstract boolean suspendLockingInterruptibly(long waitTimeMillis) throws InterruptedException
suspendLocking(long)
with waitTimeMillis insteadwaitTimeMillis
milliseconds have passed without successfully
granting suspension.waitTimeMillis
- the number of milliseconds to try to acquire
suspension before giving up and returning false. A value
of -1 causes this method to block until suspension is granted.waitTimeMillis
passed before it could
be granted.IllegalStateException
- if the current thread already has
suspended locking on this instance.InterruptedException
- if the current thread is interrupted.LockServiceDestroyedException
- if the service has been destroyedpublic abstract boolean suspendLocking(long waitTimeMillis)
waitTimeMillis
milliseconds have passed without successfully
granting suspension.waitTimeMillis
- the number of milliseconds to try to acquire
suspension before giving up and returning false. A value of -1 causes
this method to block until suspension is granted. A value of 0 causes
this method to return false without waiting for the lock if the lock is
held by another member or thread.waitTimeMillis
passed before it could
be granted.IllegalStateException
- if the current thread already has
suspended locking on this instanceLockServiceDestroyedException
- if the service has been destroyedpublic abstract void resumeLocking()
IllegalStateException
- if the current thread didn't previously
suspend lockingLockServiceDestroyedException
- if the service has been destroyedpublic abstract boolean isLockingSuspendedByCurrentThread()
LockServiceDestroyedException
- if this service has been destroyedpublic abstract void freeResources(Object name)
name
.
This may reduce this VM's memory use, but may also prohibit performance
optimizations if name
is subsequently locked in this
VM.LockServiceDestroyedException
- if this service has been destroyedpublic abstract void becomeLockGrantor()
Calls to this method will block until grantor authority has been transferred to this member.
If another member calls becomeLockGrantor
after this member,
that member will transfer grantor authority from this member to itself.
This operation should not be invoked repeatedly in an application. It is possible to create a lock service and have two or more members endlessly calling becomeLockGrantor to transfer grantorship back and forth.
LockServiceDestroyedException
- if this service has been destroyedpublic static void becomeLockGrantor(String serviceName) throws IllegalArgumentException
serviceName
- the name of the locking serviceIllegalArgumentException
- if serviceName does not
refer to any registered locking service in this process
becomeLockGrantor()
public abstract boolean isLockGrantor()
becomeLockGrantor()
.
If no member has explicitly requested grantor authority, then one member
participating in the service will be implicitly selected. In either case,
this method returns true if the calling member is the grantor.LockServiceDestroyedException
- if lock service has been destroyedpublic static boolean isLockGrantor(String serviceName) throws IllegalArgumentException
serviceName
- the name of the locking serviceIllegalArgumentException
- if serviceName does not
refer to any registered locking service in this process
isLockGrantor()
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