|
ehcache | |||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | |||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
java.lang.Object java.lang.Number net.sf.ehcache.util.concurrent.LongAdder
public class LongAdder
One or more variables that together maintain an initially zero
long
sum. When updates (method add(long)
) are contended
across threads, the set of variables may grow dynamically to reduce
contention. Method sum()
(or, equivalently, longValue()
) returns the current total combined across the
variables maintaining the sum.
This class is usually preferable to AtomicLong
when
multiple threads update a common sum that is used for purposes such
as collecting statistics, not for fine-grained synchronization
control. Under low update contention, the two classes have similar
characteristics. But under high contention, expected throughput of
this class is significantly higher, at the expense of higher space
consumption.
This class extends Number
, but does not define
methods such as hashCode
and compareTo
because
instances are expected to be mutated, and so are not useful as
collection keys.
jsr166e note: This class is targeted to be placed in java.util.concurrent.atomic.
Constructor Summary | |
---|---|
LongAdder()
Creates a new adder with initial sum of zero. |
Method Summary | |
---|---|
void |
add(long x)
Adds the given value. |
void |
decrement()
Equivalent to add(-1) . |
double |
doubleValue()
Returns the sum() as a double after a widening
primitive conversion. |
float |
floatValue()
Returns the sum() as a float
after a widening primitive conversion. |
void |
increment()
Equivalent to add(1) . |
int |
intValue()
Returns the sum() as an int after a narrowing
primitive conversion. |
long |
longValue()
Equivalent to sum() . |
void |
reset()
Resets variables maintaining the sum to zero. |
long |
sum()
Returns the current sum. |
long |
sumThenReset()
Equivalent in effect to sum() followed by reset() . |
String |
toString()
Returns the String representation of the sum() . |
Methods inherited from class java.lang.Number |
---|
byteValue, shortValue |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Constructor Detail |
---|
public LongAdder()
Method Detail |
---|
public void add(long x)
x
- the value to addpublic void increment()
add(1)
.
public void decrement()
add(-1)
.
public long sum()
public void reset()
public long sumThenReset()
sum()
followed by reset()
. This method may apply for example during quiescent
points between multithreaded computations. If there are
updates concurrent with this method, the returned value is
not guaranteed to be the final value occurring before
the reset.
public String toString()
sum()
.
toString
in class Object
sum()
public long longValue()
sum()
.
longValue
in class Number
public int intValue()
sum()
as an int
after a narrowing
primitive conversion.
intValue
in class Number
public float floatValue()
sum()
as a float
after a widening primitive conversion.
floatValue
in class Number
public double doubleValue()
sum()
as a double
after a widening
primitive conversion.
doubleValue
in class Number
|
ehcache | |||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | |||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |