Package org.agrona.concurrent.status
Class AtomicCounter
- java.lang.Object
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- org.agrona.concurrent.status.AtomicCounter
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- All Implemented Interfaces:
java.lang.AutoCloseable
public class AtomicCounter extends java.lang.Object implements java.lang.AutoCloseable
Atomic counter that is backed by anAtomicBuffer
that can be read across threads and processes.
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Field Summary
Fields Modifier and Type Field Description private long
addressOffset
private byte[]
byteArray
private java.nio.ByteBuffer
byteBuffer
private CountersManager
countersManager
private int
id
private boolean
isClosed
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Constructor Summary
Constructors Constructor Description AtomicCounter(AtomicBuffer buffer, int counterId)
Map a counter over a buffer.AtomicCounter(AtomicBuffer buffer, int counterId, CountersManager countersManager)
Map a counter over a buffer.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description AtomicCounter
appendToLabel(java.lang.String suffix)
Append to the label for a counter constructed with aCountersManager
.void
close()
Close counter and free the counter slot for reuse of connected toCountersManager
.boolean
compareAndSet(long expectedValue, long updateValue)
Compare the current value to expected and if true then set to the update value atomically.long
decrement()
Perform an atomic decrement that will not lose updates across threads.long
decrementOrdered()
Perform an atomic decrement that is not safe across threads.void
disconnectCountersManager()
Disconnect fromCountersManager
if allocated, so it can be closed without freeing the slot.long
get()
Get the latest value for the counter with volatile semantics.long
getAndAdd(long increment)
Add an increment to the counter that will not lose updates across threads.long
getAndAddOrdered(long increment)
Add an increment to the counter with ordered store semantics.long
getAndSet(long value)
Get the current value of a counter and atomically set it to a new value.long
getWeak()
Get the value of the counter using weak ordering semantics.int
id()
Identity for the counter within theCountersManager
.long
increment()
Perform an atomic increment that will not lose updates across threads.long
incrementOrdered()
Perform an atomic increment that is not safe across threads.boolean
isClosed()
Has this counter been closed?java.lang.String
label()
Return the label for the counter within theCountersManager
.boolean
proposeMax(long proposedValue)
Set the value to a new proposedValue if greater than the current value with memory ordering semantics.boolean
proposeMaxOrdered(long proposedValue)
Set the value to a new proposedValue if greater than the current value with memory ordering semantics.void
set(long value)
Set the counter with volatile semantics.void
setOrdered(long value)
Set the counter with ordered semantics.void
setWeak(long value)
Set the counter with normal semantics.java.lang.String
toString()
void
updateKey(java.util.function.Consumer<MutableDirectBuffer> keyFunc)
Update the key for a counter constructed with aCountersManager
.void
updateKey(DirectBuffer keyBuffer, int offset, int length)
Update the key for a counter constructed with aCountersManager
.void
updateLabel(java.lang.String newLabel)
Update the label for the counter constructed with aCountersManager
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Field Detail
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isClosed
private boolean isClosed
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id
private final int id
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addressOffset
private final long addressOffset
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byteArray
private final byte[] byteArray
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countersManager
private CountersManager countersManager
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byteBuffer
private final java.nio.ByteBuffer byteBuffer
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Constructor Detail
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AtomicCounter
public AtomicCounter(AtomicBuffer buffer, int counterId)
Map a counter over a buffer. This version will NOT free the counter on close.- Parameters:
buffer
- containing the counter.counterId
- identifier of the counter.
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AtomicCounter
public AtomicCounter(AtomicBuffer buffer, int counterId, CountersManager countersManager)
Map a counter over a buffer. This version will free the counter on close.- Parameters:
buffer
- containing the counter.counterId
- identifier for the counter.countersManager
- to be called to free the counter on close.
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Method Detail
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id
public int id()
Identity for the counter within theCountersManager
.- Returns:
- identity for the counter within the
CountersManager
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disconnectCountersManager
public void disconnectCountersManager()
Disconnect fromCountersManager
if allocated, so it can be closed without freeing the slot.
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close
public void close()
Close counter and free the counter slot for reuse of connected toCountersManager
.- Specified by:
close
in interfacejava.lang.AutoCloseable
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isClosed
public boolean isClosed()
Has this counter been closed?- Returns:
- true if this counter has already been closed.
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label
public java.lang.String label()
Return the label for the counter within theCountersManager
.- Returns:
- the label for the counter within the
CountersManager
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updateLabel
public void updateLabel(java.lang.String newLabel)
Update the label for the counter constructed with aCountersManager
.- Parameters:
newLabel
- for the counter with aCountersManager
.- Throws:
java.lang.IllegalStateException
- is not constructedCountersManager
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appendToLabel
public AtomicCounter appendToLabel(java.lang.String suffix)
Append to the label for a counter constructed with aCountersManager
.- Parameters:
suffix
- for the counter within aCountersManager
.- Returns:
- this for a fluent API.
- Throws:
java.lang.IllegalStateException
- is not constructedCountersManager
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updateKey
public void updateKey(java.util.function.Consumer<MutableDirectBuffer> keyFunc)
Update the key for a counter constructed with aCountersManager
.- Parameters:
keyFunc
- callback to use to update the counter's key- Throws:
java.lang.IllegalStateException
- is not constructedCountersManager
.
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updateKey
public void updateKey(DirectBuffer keyBuffer, int offset, int length)
Update the key for a counter constructed with aCountersManager
.- Parameters:
keyBuffer
- contains key data to be copied into the counter.offset
- start of the key data within the keyBufferlength
- length of the data within the keyBuffer (must be <=CountersReader.MAX_KEY_LENGTH
)- Throws:
java.lang.IllegalStateException
- is not constructedCountersManager
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increment
public long increment()
Perform an atomic increment that will not lose updates across threads.- Returns:
- the previous value of the counter
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incrementOrdered
public long incrementOrdered()
Perform an atomic increment that is not safe across threads.- Returns:
- the previous value of the counter
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decrement
public long decrement()
Perform an atomic decrement that will not lose updates across threads.- Returns:
- the previous value of the counter
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decrementOrdered
public long decrementOrdered()
Perform an atomic decrement that is not safe across threads.- Returns:
- the previous value of the counter
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set
public void set(long value)
Set the counter with volatile semantics.- Parameters:
value
- to be set with volatile semantics.
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setOrdered
public void setOrdered(long value)
Set the counter with ordered semantics.- Parameters:
value
- to be set with ordered semantics.
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setWeak
public void setWeak(long value)
Set the counter with normal semantics.- Parameters:
value
- to be set with normal semantics.
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getAndAdd
public long getAndAdd(long increment)
Add an increment to the counter that will not lose updates across threads.- Parameters:
increment
- to be added.- Returns:
- the previous value of the counter
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getAndAddOrdered
public long getAndAddOrdered(long increment)
Add an increment to the counter with ordered store semantics.- Parameters:
increment
- to be added with ordered store semantics.- Returns:
- the previous value of the counter
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getAndSet
public long getAndSet(long value)
Get the current value of a counter and atomically set it to a new value.- Parameters:
value
- to be set.- Returns:
- the previous value of the counter
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compareAndSet
public boolean compareAndSet(long expectedValue, long updateValue)
Compare the current value to expected and if true then set to the update value atomically.- Parameters:
expectedValue
- for the counter.updateValue
- for the counter.- Returns:
- true if successful otherwise false.
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get
public long get()
Get the latest value for the counter with volatile semantics.- Returns:
- the latest value for the counter.
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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.
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proposeMax
public boolean proposeMax(long proposedValue)
Set the value to a new proposedValue if greater than the current value with memory ordering semantics.- Parameters:
proposedValue
- for the new max.- Returns:
- true if a new max as been set otherwise false.
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proposeMaxOrdered
public boolean proposeMaxOrdered(long proposedValue)
Set the value to a new proposedValue if greater than the current value with memory ordering semantics.- Parameters:
proposedValue
- for the new max.- Returns:
- true if a new max as been set otherwise false.
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toString
public java.lang.String toString()
- Overrides:
toString
in classjava.lang.Object
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