io.aeron.status

Class ReadableCounter

java.lang.Object

io.aeron.status.ReadableCounter

All Implemented Interfaces:

java.lang.AutoCloseable

public class ReadableCounter
extends java.lang.Object
implements java.lang.AutoCloseable

Readonly View of an associated Counter.

Note:The user should call isClosed() and ensure the result is false to avoid a race on reading a closed counter.

Constructor Summary

Constructors

Constructor and Description
ReadableCounter(org.agrona.concurrent.status.CountersReader countersReader, int counterId) Construct a view of an existing counter.
ReadableCounter(org.agrona.concurrent.status.CountersReader countersReader, long registrationId, int counterId) Construct a view of an existing counter.

Method Summary

Modifier and Type	Method and Description
void	close() Close this counter.
int	counterId() Return the counter Id.
long	get() Get the latest value for the counter with volatile semantics.
long	getWeak() Get the value of the counter using weak ordering semantics.
boolean	isClosed() Has this counters been closed and should no longer be used?
java.lang.String	label() Return the counter label.
long	registrationId() Return the registration Id for the counter.
int	state() Return the state of the counter.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReadableCounter

public ReadableCounter(org.agrona.concurrent.status.CountersReader countersReader,
                       long registrationId,
                       int counterId)

Construct a view of an existing counter.

Parameters:

countersReader - for getting access to the buffers.

registrationId - assigned by the driver for the counter or -1 if not known.

counterId - for the counter to be viewed.

Throws:

java.lang.IllegalStateException - if the id has for the counter has not been allocated.

ReadableCounter

public ReadableCounter(org.agrona.concurrent.status.CountersReader countersReader,
                       int counterId)

Construct a view of an existing counter.

Parameters:

countersReader - for getting access to the buffers.

counterId - for the counter to be viewed.

Throws:

java.lang.IllegalStateException - if the id has for the counter has not been allocated.

Method Detail

registrationId

public long registrationId()

Return the registration Id for the counter.

Returns:

registration Id.

counterId

public int counterId()

Return the counter Id.

Returns:

counter Id.

state

public int state()

Return the state of the counter.

Returns:

state for the counter.

See Also:

CountersReader.RECORD_ALLOCATED, CountersReader.RECORD_LINGERING, CountersReader.RECORD_RECLAIMED, CountersReader.RECORD_UNUSED

label

public java.lang.String label()

Return the counter label.

Returns:

the counter label.

get

public long get()

Get the latest value for the counter with volatile semantics.

Note:The user should call isClosed() and ensure the result is false to avoid a race on reading a closed counter.

Returns:

the latest value for the counter.

getWeak

public long getWeak()

Get the value of the counter using weak ordering semantics. This is the same a standard read of a field.

Returns:

the value for the counter.

close

public void close()

Close this counter. This has no impact on the Counter it is viewing.

Specified by:

close in interface java.lang.AutoCloseable

isClosed

public boolean isClosed()

Has this counters been closed and should no longer be used?

Returns:

true if it has been closed otherwise false.