Package org.apache.jmeter.util
Class ThreadLocalRandom
- java.lang.Object
-
- java.util.Random
-
- org.apache.jmeter.util.ThreadLocalRandom
-
- All Implemented Interfaces:
Serializable
public class ThreadLocalRandom extends Random
A random number generator isolated to the current thread. Like the globalRandom
generator used by theMath
class, aThreadLocalRandom
is initialized with an internally generated seed that may not otherwise be modified. When applicable, use ofThreadLocalRandom
rather than sharedRandom
objects in concurrent programs will typically encounter much less overhead and contention. Use ofThreadLocalRandom
is particularly appropriate when multiple tasks (for example, each a java.util.concurrent.ForkJoinTask (JDK 1.7)) use random numbers in parallel in thread pools.Usages of this class should typically be of the form:
ThreadLocalRandom.current().nextX(...)
(whereX
isInt
,Long
, etc). When all usages are of this form, it is never possible to accidently share aThreadLocalRandom
across multiple threads.This class also provides additional commonly used bounded random generation methods.
- Since:
- 2.12
- Author:
- Doug Lea TODO Remove when minimum Java Version become Java 7
- See Also:
- Serialized Form
-
-
Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description static ThreadLocalRandom
current()
Returns the current thread'sThreadLocalRandom
.protected int
next(int bits)
double
nextDouble(double n)
Returns a pseudorandom, uniformly distributeddouble
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)
ThrowsUnsupportedOperationException
.
-
-
-
Method Detail
-
current
public static ThreadLocalRandom current()
Returns the current thread'sThreadLocalRandom
.- Returns:
- the current thread's
ThreadLocalRandom
-
setSeed
public void setSeed(long seed)
ThrowsUnsupportedOperationException
. Setting seeds in this generator is not supported.- Overrides:
setSeed
in classRandom
- Throws:
UnsupportedOperationException
- always
-
nextInt
public int nextInt(int least, int bound)
Returns a pseudorandom, uniformly distributed value between the given least value (inclusive) and bound (exclusive).- Parameters:
least
- the least value returnedbound
- the upper bound (exclusive)- Returns:
- the next value
- Throws:
IllegalArgumentException
- if least greater than or equal to bound
-
nextLong
public long nextLong(long n)
Returns a pseudorandom, uniformly distributed value between 0 (inclusive) and the specified value (exclusive).- Parameters:
n
- the bound on the random number to be returned. Must be positive.- Returns:
- the next value
- Throws:
IllegalArgumentException
- if n is not positive
-
nextLong
public long nextLong(long least, long bound)
Returns a pseudorandom, uniformly distributed value between the given least value (inclusive) and bound (exclusive).- Parameters:
least
- the least value returnedbound
- the upper bound (exclusive)- Returns:
- the next value
- Throws:
IllegalArgumentException
- if least greater than or equal to bound
-
nextDouble
public double nextDouble(double n)
Returns a pseudorandom, uniformly distributeddouble
value between 0 (inclusive) and the specified value (exclusive).- Parameters:
n
- the bound on the random number to be returned. Must be positive.- Returns:
- the next value
- Throws:
IllegalArgumentException
- if n is not positive
-
nextDouble
public double nextDouble(double least, double bound)
Returns a pseudorandom, uniformly distributed value between the given least value (inclusive) and bound (exclusive).- Parameters:
least
- the least value returnedbound
- the upper bound (exclusive)- Returns:
- the next value
- Throws:
IllegalArgumentException
- if least greater than or equal to bound
-
-