Package com.oracle.coherence.concurrent.internal

Class SemaphoreStatus

java.lang.Object

com.oracle.coherence.concurrent.internal.SemaphoreStatus

All Implemented Interfaces:

ExternalizableLite, PortableObject, Serializable

public class SemaphoreStatus
extends Object
implements ExternalizableLite, PortableObject

A data structure that encapsulates server-side semaphore logic.

Since:

21.12

Author:

Vaso Putica 2021.11.30

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	SemaphoreStatus.RemovePermits	An EntryProcessor that will remove acquired permits for the provided member ID, or all the permits for the members that are not in the cluster any longer.

Constructor Summary

Constructors

Constructor	Description
SemaphoreStatus()	Default constructor (necessary for the ExternalizableLite interface).
SemaphoreStatus(int initialState)	Create an instance of SemaphoreStatus.

Method Summary

Modifier and Type	Method	Description
boolean	acquire(PermitAcquirer acquirer, int permits)	Acquires the given number of permits for specified acquirer.
int	drainPermits(PermitAcquirer acquirer)
int	getInitialPermits()	Returns number of permits that were used to initialise this semaphore.
UID	getMember()	Returns the identity of member who most recently updated the semaphore.
int	getPermits()	Returns the current number of permits available.
boolean	isAcquiredBy(PermitAcquirer acquirer)
void	readExternal(PofReader in)
void	readExternal(DataInput in)
int	reducePermits(PermitAcquirer acquirer, int reductions)
boolean	release(PermitAcquirer acquirer, int releases)	Releases the given number of permits, returning them to the semaphore.
protected boolean	removePermitsFor(UID memberId)	Remove all the permits that are acquired by a specified member.
protected boolean	retainPermitsFor(Set<UID> setMemberIds)	Remove all the permits that are not acquired by one of the specified members.
void	setMember(UID member)	Sets the identity of member who most recently updated the semaphore.
void	setPermits(int permits)	Sets the number of permits available.
String	toString()
void	writeExternal(PofWriter out)
void	writeExternal(DataOutput out)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

SemaphoreStatus

public SemaphoreStatus()

Default constructor (necessary for the ExternalizableLite interface).

SemaphoreStatus

public SemaphoreStatus(int initialState)

Create an instance of SemaphoreStatus.

Parameters:

initialState - the initial number of permits available

Method Detail

acquire

public boolean acquire(PermitAcquirer acquirer,
                       int permits)

Acquires the given number of permits for specified acquirer.

Parameters:

acquirer - identity of the acquirer

permits - the number of permits to acquire

Returns:

true if permits were acquired; otherwise returns false

release

public boolean release(PermitAcquirer acquirer,
                       int releases)

Releases the given number of permits, returning them to the semaphore.

Parameters:

acquirer - identity of the acquirer

releases - the number of permits to release

Returns:

true if permits were released; otherwise returns false

drainPermits

public int drainPermits(PermitAcquirer acquirer)

reducePermits

public int reducePermits(PermitAcquirer acquirer,
                         int reductions)

getPermits

public int getPermits()

Returns the current number of permits available.

Returns:

the number of permits available

setPermits

public void setPermits(int permits)

Sets the number of permits available.

Parameters:

permits - the number of permits available

getMember

public UID getMember()

Returns the identity of member who most recently updated the semaphore.

Returns:

the identity of member who most recently updated the semaphore.

setMember

public void setMember(UID member)

Sets the identity of member who most recently updated the semaphore.

Parameters:

member - the identity of member who most recently updated the semaphore

isAcquiredBy

public boolean isAcquiredBy(PermitAcquirer acquirer)

retainPermitsFor

protected boolean retainPermitsFor(Set<UID> setMemberIds)

Remove all the permits that are not acquired by one of the specified members.

Parameters:

setMemberIds - theUIDs of the member to retain the locks for

Returns:

true if this semaphore was modified

removePermitsFor

protected boolean removePermitsFor(UID memberId)

Remove all the permits that are acquired by a specified member.

Parameters:

memberId - the UID of a member to remove the permits for

Returns:

true if this holder was modified

getInitialPermits

public int getInitialPermits()

Returns number of permits that were used to initialise this semaphore.

Returns:

initial number of permits that were used to initialise this semaphore.

toString

public String toString()

Overrides:

toString in class Object

readExternal

public void readExternal(DataInput in)
                  throws IOException

Specified by:

readExternal in interface ExternalizableLite

Throws:

IOException

writeExternal

public void writeExternal(DataOutput out)
                   throws IOException

Specified by:

writeExternal in interface ExternalizableLite

Throws:

IOException

readExternal

public void readExternal(PofReader in)
                  throws IOException

Specified by:

readExternal in interface PortableObject

Throws:

IOException

writeExternal

public void writeExternal(PofWriter out)
                   throws IOException

Specified by:

writeExternal in interface PortableObject

Throws:

IOException