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java.lang.Object java.util.Random net.sf.ehcache.util.concurrent.ThreadLocalRandom
public class ThreadLocalRandom
A random number generator isolated to the current thread. Like the
global Random
generator used by the Math
class, a ThreadLocalRandom
is initialized
with an internally generated seed that may not otherwise be
modified. When applicable, use of ThreadLocalRandom
rather
than shared Random
objects in concurrent programs will
typically encounter much less overhead and contention. Use of
ThreadLocalRandom
is particularly appropriate when multiple
tasks (for example, each a ForkJoinTask
) use random numbers
in parallel in thread pools.
Usages of this class should typically be of the form:
ThreadLocalRandom.current().nextX(...)
(where
X
is Int
, Long
, etc).
When all usages are of this form, it is never possible to
accidently share a ThreadLocalRandom
across multiple threads.
This class also provides additional commonly used bounded random generation methods.
Method Summary | |
---|---|
static ThreadLocalRandom |
current()
Returns the current thread's ThreadLocalRandom . |
protected int |
next(int bits)
|
double |
nextDouble(double n)
Returns a pseudorandom, uniformly distributed double value
between 0 (inclusive) and the specified value (exclusive). |
double |
nextDouble(double least,
double bound)
Returns a pseudorandom, uniformly distributed value between the given least value (inclusive) and bound (exclusive). |
int |
nextInt(int least,
int bound)
Returns a pseudorandom, uniformly distributed value between the given least value (inclusive) and bound (exclusive). |
long |
nextLong(long n)
Returns a pseudorandom, uniformly distributed value between 0 (inclusive) and the specified value (exclusive). |
long |
nextLong(long least,
long bound)
Returns a pseudorandom, uniformly distributed value between the given least value (inclusive) and bound (exclusive). |
void |
setSeed(long seed)
Throws UnsupportedOperationException . |
Methods inherited from class java.util.Random |
---|
nextBoolean, nextBytes, nextDouble, nextFloat, nextGaussian, nextInt, nextInt, nextLong |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Method Detail |
---|
public static ThreadLocalRandom current()
ThreadLocalRandom
.
ThreadLocalRandom
public void setSeed(long seed)
UnsupportedOperationException
. Setting seeds in
this generator is not supported.
setSeed
in class Random
UnsupportedOperationException
- alwaysprotected int next(int bits)
next
in class Random
public int nextInt(int least, int bound)
least
- the least value returnedbound
- the upper bound (exclusive)
IllegalArgumentException
- if least greater than or equal
to boundpublic long nextLong(long n)
n
- the bound on the random number to be returned. Must be
positive.
IllegalArgumentException
- if n is not positivepublic long nextLong(long least, long bound)
least
- the least value returnedbound
- the upper bound (exclusive)
IllegalArgumentException
- if least greater than or equal
to boundpublic double nextDouble(double n)
double
value
between 0 (inclusive) and the specified value (exclusive).
n
- the bound on the random number to be returned. Must be
positive.
IllegalArgumentException
- if n is not positivepublic double nextDouble(double least, double bound)
least
- the least value returnedbound
- the upper bound (exclusive)
IllegalArgumentException
- if least greater than or equal
to bound
|
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