Oracle® Coherence Java API Reference
v3.5

E14977-01

com.tangosol.util
Class AtomicCounter

java.lang.Object
  extended by com.tangosol.util.Base
      extended by com.tangosol.util.AtomicCounter

public abstract class AtomicCounter
extends Base

Abstract base class for AtomicCounters. The AtomicCounter allows for atomic updates to a "long" value where possible without requiring synchronization. The underlying AtomicCounter impelementation will be choosen based at runtime.

Since:
Coherence 3.2
Author:
mf 2006.05.09

Field Summary
protected static java.lang.Class s_clzImplementation
          The counter implementation which will be used.
 
Constructor Summary
AtomicCounter()
           
 
Method Summary
protected abstract  long adjust(long c)
          Adjust the value of the counter by the specified amount, and return the new value.
 long decrement()
          Decrement the value, and return the new value.
 long decrement(long c)
          Decrement the value by c, and return the new value.
abstract  long getCount()
          Return the current value of the counter.
 long increment()
          Incremenet the value, and return the new value.
 long increment(long c)
          Incremenet the value by c, and return the new value.
static AtomicCounter newAtomicCounter()
          Instantiate and return a new AtomicCounter.
static AtomicCounter newAtomicCounter(long l)
          Instantiate and return a new AtomicCounter initialized to a particular value.
protected abstract  long postAdjust(long c)
          Adjust the value of the counter by the specified amount, and return the old value.
 long postDecrement()
          Decrement the value, and return the original value.
 long postDecrement(long c)
          Decrement the value by c, and return the original value.
 long postIncrement()
          Incremenet the value, and return the original value.
 long postIncrement(long c)
          Incremenet the value by c, and return the original value.
abstract  long setCount(long cNew)
          Update the current value, and return the previous value.
abstract  boolean setCount(long cAssume, long cNew)
          Update the current value, only if it is equal to the assumed value.
 java.lang.String toString()
          Return the count as a string.
 

Field Detail

s_clzImplementation

protected static java.lang.Class s_clzImplementation
The counter implementation which will be used.

Constructor Detail

AtomicCounter

public AtomicCounter()
Method Detail

increment

public long increment()
Incremenet the value, and return the new value.

Returns:
the new value

increment

public long increment(long c)
Incremenet the value by c, and return the new value.

Parameters:
c - the amount to increment the counter by
Returns:
the new value

postIncrement

public long postIncrement()
Incremenet the value, and return the original value.

Returns:
the original value

postIncrement

public long postIncrement(long c)
Incremenet the value by c, and return the original value.

Parameters:
c - the amount to increment the counter by
Returns:
the original value

decrement

public long decrement()
Decrement the value, and return the new value.

Returns:
the new value

decrement

public long decrement(long c)
Decrement the value by c, and return the new value.

Parameters:
c - the amount to decrement the counter by
Returns:
the new value

postDecrement

public long postDecrement()
Decrement the value, and return the original value.

Returns:
the original value

postDecrement

public long postDecrement(long c)
Decrement the value by c, and return the original value.

Parameters:
c - the amount to decrement the counter by
Returns:
the original value

getCount

public abstract long getCount()
Return the current value of the counter.

Returns:
the current value

setCount

public abstract boolean setCount(long cAssume,
                                 long cNew)
Update the current value, only if it is equal to the assumed value.

Parameters:
cAssume - the assumed old value
cNew - the new value
Returns:
true if the value was updated, false otherwise

setCount

public abstract long setCount(long cNew)
Update the current value, and return the previous value.

Parameters:
cNew - the new value
Returns:
the previous value just before the update went through

toString

public java.lang.String toString()
Return the count as a string.

Returns:
a string represenation of the count

adjust

protected abstract long adjust(long c)
Adjust the value of the counter by the specified amount, and return the new value.

Parameters:
c - the amount to adjust the counter by
Returns:
the new value, after the adjustment has been made

postAdjust

protected abstract long postAdjust(long c)
Adjust the value of the counter by the specified amount, and return the old value.

Parameters:
c - the amount to adjust the counter by
Returns:
the old value, prior to the adjustment having been made

newAtomicCounter

public static AtomicCounter newAtomicCounter()
Instantiate and return a new AtomicCounter. The underlying implementation be choosen based on the JVM.

Returns:
a new AtomicCounter with a count of zero

newAtomicCounter

public static AtomicCounter newAtomicCounter(long l)
Instantiate and return a new AtomicCounter initialized to a particular value.

Parameters:
l - the initial counter value
Returns:
a new AtomicCounter with the specified counter value

Oracle® Coherence Java API Reference
v3.5

E14977-01

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