Package com.lmax.disruptor
Class Sequence
- java.lang.Object
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- com.lmax.disruptor.LhsPadding
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- com.lmax.disruptor.Value
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- com.lmax.disruptor.RhsPadding
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- com.lmax.disruptor.Sequence
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- Direct Known Subclasses:
FixedSequenceGroup
,NoOpEventProcessor.SequencerFollowingSequence
,SequenceGroup
public class Sequence extends RhsPadding
Concurrent sequence class used for tracking the progress of the ring buffer and event processors. Support a number of concurrent operations including CAS and order writes.
Also attempts to be more efficient with regards to false sharing by adding padding around the volatile field.
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Field Summary
Fields Modifier and Type Field Description (package private) static long
INITIAL_VALUE
private static sun.misc.Unsafe
UNSAFE
private static long
VALUE_OFFSET
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description long
addAndGet(long increment)
Atomically add the supplied value.boolean
compareAndSet(long expectedValue, long newValue)
Perform a compare and set operation on the sequence.long
get()
Perform a volatile read of this sequence's value.long
incrementAndGet()
Atomically increment the sequence by one.void
set(long value)
Perform an ordered write of this sequence.void
setVolatile(long value)
Performs a volatile write of this sequence.java.lang.String
toString()
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Field Detail
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INITIAL_VALUE
static final long INITIAL_VALUE
- See Also:
- Constant Field Values
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UNSAFE
private static final sun.misc.Unsafe UNSAFE
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VALUE_OFFSET
private static final long VALUE_OFFSET
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Method Detail
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get
public long get()
Perform a volatile read of this sequence's value.- Returns:
- The current value of the sequence.
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set
public void set(long value)
Perform an ordered write of this sequence. The intent is a Store/Store barrier between this write and any previous store.- Parameters:
value
- The new value for the sequence.
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setVolatile
public void setVolatile(long value)
Performs a volatile write of this sequence. The intent is a Store/Store barrier between this write and any previous write and a Store/Load barrier between this write and any subsequent volatile read.- Parameters:
value
- The new value for the sequence.
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compareAndSet
public boolean compareAndSet(long expectedValue, long newValue)
Perform a compare and set operation on the sequence.- Parameters:
expectedValue
- The expected current value.newValue
- The value to update to.- Returns:
- true if the operation succeeds, false otherwise.
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incrementAndGet
public long incrementAndGet()
Atomically increment the sequence by one.- Returns:
- The value after the increment
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addAndGet
public long addAndGet(long increment)
Atomically add the supplied value.- Parameters:
increment
- The value to add to the sequence.- Returns:
- The value after the increment.
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toString
public java.lang.String toString()
- Overrides:
toString
in classjava.lang.Object
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