Class ThreadLocalRandom

Method Details

• current

  public static ThreadLocalRandom current()

  Returns the current thread's ThreadLocalRandom object. Methods of this object should be called only by the current thread, not by other threads.

  Returns:

  the current thread's ThreadLocalRandom

• setSeed

  public void setSeed(long seed)

  Throws UnsupportedOperationException. Setting seeds in this generator is not supported.

  Overrides:

  setSeed in class Random

  Parameters:

  seed - the seed value

  Throws:

  UnsupportedOperationException - always

• next

  protected int next(int bits)

  Generates a pseudorandom number with the indicated number of low-order bits. Because this class has no subclasses, this method cannot be invoked or overridden.

  Overrides:

  next in class Random

  Parameters:

  bits - random bits

  Returns:

  the next pseudorandom value from this random number generator's sequence

• nextInt

  public int nextInt(int bound)

  Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence. The general contract of nextInt is that one int value in the specified range is pseudorandomly generated and returned. All bound possible int values are produced with (approximately) equal probability.

  Specified by:

  nextInt in interface RandomGenerator

  Overrides:

  nextInt in class Random

  Parameters:

  bound - the upper bound (exclusive). Must be positive.

  Returns:

  the next pseudorandom, uniformly distributed int value between zero (inclusive) and bound (exclusive) from this random number generator's sequence

  Throws:

  IllegalArgumentException - if bound is not positive

• nextInt

  public int nextInt(int origin, int bound)

  Returns a pseudorandomly chosen int value between the specified origin (inclusive) and the specified bound (exclusive).

  Parameters:

  origin - the least value that can be returned

  bound - the upper bound (exclusive) for the returned value

  Returns:

  a pseudorandomly chosen int value between the origin (inclusive) and the bound (exclusive)

  Throws:

  IllegalArgumentException - if origin is greater than or equal to bound

• nextLong

  public long nextLong(long bound)

  Returns a pseudorandomly chosen long value between zero (inclusive) and the specified bound (exclusive).

  Parameters:

  bound - the upper bound (exclusive) for the returned value. Must be positive.

  Returns:

  a pseudorandomly chosen long value between zero (inclusive) and the bound (exclusive)

  Throws:

  IllegalArgumentException - if bound is not positive

• nextLong

  public long nextLong(long origin, long bound)

  Returns a pseudorandomly chosen long value between the specified origin (inclusive) and the specified bound (exclusive).

  Parameters:

  origin - the least value that can be returned

  bound - the upper bound (exclusive) for the returned value

  Returns:

  a pseudorandomly chosen long value between the origin (inclusive) and the bound (exclusive)

  Throws:

  IllegalArgumentException - if origin is greater than or equal to bound

• nextFloat

  public float nextFloat(float bound)

  Returns a pseudorandomly chosen float value between zero (inclusive) and the specified bound (exclusive).

  Implementation Note:

  Parameters:

  bound - the upper bound (exclusive) for the returned value. Must be positive and finite

  Returns:

  a pseudorandomly chosen float value between zero (inclusive) and the bound (exclusive)

  Throws:

  IllegalArgumentException - if bound is not both positive and finite

• nextFloat

  public float nextFloat(float origin, float bound)

  Returns a pseudorandomly chosen float value between the specified origin (inclusive) and the specified bound (exclusive).

  Implementation Note:

  Parameters:

  origin - the least value that can be returned

  bound - the upper bound (exclusive)

  Returns:

  a pseudorandomly chosen float value between the origin (inclusive) and the bound (exclusive)

  Throws:

  IllegalArgumentException - if origin is not finite, or bound is not finite, or origin is greater than or equal to bound

• nextDouble

  public double nextDouble(double bound)

  Returns a pseudorandomly chosen double value between zero (inclusive) and the specified bound (exclusive).

  Implementation Note:

  Parameters:

  bound - the upper bound (exclusive) for the returned value. Must be positive and finite

  Returns:

  a pseudorandomly chosen double value between zero (inclusive) and the bound (exclusive)

  Throws:

  IllegalArgumentException - if bound is not both positive and finite

• nextDouble

  public double nextDouble(double origin, double bound)

  Returns a pseudorandomly chosen double value between the specified origin (inclusive) and the specified bound (exclusive).

  Implementation Note:

  Parameters:

  origin - the least value that can be returned

  bound - the upper bound (exclusive) for the returned value

  Returns:

  a pseudorandomly chosen double value between the origin (inclusive) and the bound (exclusive)

  Throws:

  IllegalArgumentException - if origin is not finite, or bound is not finite, or origin is greater than or equal to bound

• ints

  public IntStream ints(long streamSize)

  Returns a stream producing the given streamSize number of pseudorandom int values.

  A pseudorandom int value is generated as if it's the result of calling the method Random.nextInt().

  Specified by:

  ints in interface RandomGenerator

  Overrides:

  ints in class Random

  Parameters:

  streamSize - the number of values to generate

  Returns:

  a stream of pseudorandom int values

  Throws:

  IllegalArgumentException - if streamSize is less than zero

  Since:

  1.8

• ints

  public IntStream ints()

  Returns an effectively unlimited stream of pseudorandom int values.

  A pseudorandom int value is generated as if it's the result of calling the method Random.nextInt().

  Specified by:

  ints in interface RandomGenerator

  Overrides:

  ints in class Random

  Implementation Note:

  This method is implemented to be equivalent to ints(Long.MAX_VALUE).

  Returns:

  a stream of pseudorandom int values

  Since:

  1.8

• ints

  public IntStream ints(long streamSize, int randomNumberOrigin, int randomNumberBound)

  Returns a stream producing the given streamSize number of pseudorandom int values, each conforming to the given origin (inclusive) and bound (exclusive).

  A pseudorandom int value is generated as if it's the result of calling the following method with the origin and bound:

   
   int nextInt(int origin, int bound) {
     int n = bound - origin;
     if (n > 0) {
       return nextInt(n) + origin;
     }
     else {  // range not representable as int
       int r;
       do {
         r = nextInt();
       } while (r < origin || r >= bound);
       return r;
     }
   }

  Specified by:

  ints in interface RandomGenerator

  Overrides:

  ints in class Random

  Parameters:

  streamSize - the number of values to generate

  randomNumberOrigin - the origin (inclusive) of each random value

  randomNumberBound - the bound (exclusive) of each random value

  Returns:

  a stream of pseudorandom int values, each with the given origin (inclusive) and bound (exclusive)

  Throws:

  IllegalArgumentException - if streamSize is less than zero, or randomNumberOrigin is greater than or equal to randomNumberBound

  Since:

  1.8

• ints

  public IntStream ints(int randomNumberOrigin, int randomNumberBound)

  Returns an effectively unlimited stream of pseudorandom int values, each conforming to the given origin (inclusive) and bound (exclusive).

  A pseudorandom int value is generated as if it's the result of calling the following method with the origin and bound:

   
   int nextInt(int origin, int bound) {
     int n = bound - origin;
     if (n > 0) {
       return nextInt(n) + origin;
     }
     else {  // range not representable as int
       int r;
       do {
         r = nextInt();
       } while (r < origin || r >= bound);
       return r;
     }
   }

  Specified by:

  ints in interface RandomGenerator

  Overrides:

  ints in class Random

  Implementation Note:

  This method is implemented to be equivalent to ints(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound).

  Parameters:

  randomNumberOrigin - the origin (inclusive) of each random value

  randomNumberBound - the bound (exclusive) of each random value

  Returns:

  a stream of pseudorandom int values, each with the given origin (inclusive) and bound (exclusive)

  Throws:

  IllegalArgumentException - if randomNumberOrigin is greater than or equal to randomNumberBound

  Since:

  1.8

• longs

  public LongStream longs(long streamSize)

  Returns a stream producing the given streamSize number of pseudorandom long values.

  A pseudorandom long value is generated as if it's the result of calling the method Random.nextLong().

  Specified by:

  longs in interface RandomGenerator

  Overrides:

  longs in class Random

  Parameters:

  streamSize - the number of values to generate

  Returns:

  a stream of pseudorandom long values

  Throws:

  IllegalArgumentException - if streamSize is less than zero

  Since:

  1.8

• longs

  public LongStream longs()

  Returns an effectively unlimited stream of pseudorandom long values.

  A pseudorandom long value is generated as if it's the result of calling the method Random.nextLong().

  Specified by:

  longs in interface RandomGenerator

  Overrides:

  longs in class Random

  Implementation Note:

  This method is implemented to be equivalent to longs(Long.MAX_VALUE).

  Returns:

  a stream of pseudorandom long values

  Since:

  1.8

• longs

  public LongStream longs(long streamSize, long randomNumberOrigin, long randomNumberBound)

  Returns a stream producing the given streamSize number of pseudorandom long, each conforming to the given origin (inclusive) and bound (exclusive).

  A pseudorandom long value is generated as if it's the result of calling the following method with the origin and bound:

   
   long nextLong(long origin, long bound) {
     long r = nextLong();
     long n = bound - origin, m = n - 1;
     if ((n & m) == 0L)  // power of two
       r = (r & m) + origin;
     else if (n > 0L) {  // reject over-represented candidates
       for (long u = r >>> 1;            // ensure nonnegative
            u + m - (r = u % n) < 0L;    // rejection check
            u = nextLong() >>> 1) // retry
           ;
       r += origin;
     }
     else {              // range not representable as long
       while (r < origin || r >= bound)
         r = nextLong();
     }
     return r;
   }

  Specified by:

  longs in interface RandomGenerator

  Overrides:

  longs in class Random

  Parameters:

  streamSize - the number of values to generate

  randomNumberOrigin - the origin (inclusive) of each random value

  randomNumberBound - the bound (exclusive) of each random value

  Returns:

  a stream of pseudorandom long values, each with the given origin (inclusive) and bound (exclusive)

  Throws:

  IllegalArgumentException - if streamSize is less than zero, or randomNumberOrigin is greater than or equal to randomNumberBound

  Since:

  1.8

• longs

  public LongStream longs(long randomNumberOrigin, long randomNumberBound)

  Returns an effectively unlimited stream of pseudorandom long values, each conforming to the given origin (inclusive) and bound (exclusive).

  A pseudorandom long value is generated as if it's the result of calling the following method with the origin and bound:

   
   long nextLong(long origin, long bound) {
     long r = nextLong();
     long n = bound - origin, m = n - 1;
     if ((n & m) == 0L)  // power of two
       r = (r & m) + origin;
     else if (n > 0L) {  // reject over-represented candidates
       for (long u = r >>> 1;            // ensure nonnegative
            u + m - (r = u % n) < 0L;    // rejection check
            u = nextLong() >>> 1) // retry
           ;
       r += origin;
     }
     else {              // range not representable as long
       while (r < origin || r >= bound)
         r = nextLong();
     }
     return r;
   }

  Specified by:

  longs in interface RandomGenerator

  Overrides:

  longs in class Random

  Implementation Note:

  This method is implemented to be equivalent to longs(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound).

  Parameters:

  randomNumberOrigin - the origin (inclusive) of each random value

  randomNumberBound - the bound (exclusive) of each random value

  Returns:

  a stream of pseudorandom long values, each with the given origin (inclusive) and bound (exclusive)

  Throws:

  IllegalArgumentException - if randomNumberOrigin is greater than or equal to randomNumberBound

  Since:

  1.8

• doubles

  public DoubleStream doubles(long streamSize)

  Returns a stream producing the given streamSize number of pseudorandom double values, each between zero (inclusive) and one (exclusive).

  A pseudorandom double value is generated as if it's the result of calling the method Random.nextDouble().

  Specified by:

  doubles in interface RandomGenerator

  Overrides:

  doubles in class Random

  Parameters:

  streamSize - the number of values to generate

  Returns:

  a stream of double values

  Throws:

  IllegalArgumentException - if streamSize is less than zero

  Since:

  1.8

• doubles

  public DoubleStream doubles()

  Returns an effectively unlimited stream of pseudorandom double values, each between zero (inclusive) and one (exclusive).

  A pseudorandom double value is generated as if it's the result of calling the method Random.nextDouble().

  Specified by:

  doubles in interface RandomGenerator

  Overrides:

  doubles in class Random

  Implementation Note:

  This method is implemented to be equivalent to doubles(Long.MAX_VALUE).

  Returns:

  a stream of pseudorandom double values

  Since:

  1.8

• doubles

  public DoubleStream doubles(long streamSize, double randomNumberOrigin, double randomNumberBound)

  Returns a stream producing the given streamSize number of pseudorandom double values, each conforming to the given origin (inclusive) and bound (exclusive).

  Specified by:

  doubles in interface RandomGenerator

  Overrides:

  doubles in class Random

  Parameters:

  streamSize - the number of values to generate

  randomNumberOrigin - the origin (inclusive) of each random value

  randomNumberBound - the bound (exclusive) of each random value

  Returns:

  a stream of pseudorandom double values, each with the given origin (inclusive) and bound (exclusive)

  Throws:

  IllegalArgumentException - if streamSize is less than zero, or randomNumberOrigin is not finite, or randomNumberBound is not finite, or randomNumberOrigin is greater than or equal to randomNumberBound

  Since:

  1.8

• doubles

  public DoubleStream doubles(double randomNumberOrigin, double randomNumberBound)

  Returns an effectively unlimited stream of pseudorandom double values, each conforming to the given origin (inclusive) and bound (exclusive).

  Specified by:

  doubles in interface RandomGenerator

  Overrides:

  doubles in class Random

  Implementation Note:

  This method is implemented to be equivalent to doubles(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound).

  Parameters:

  randomNumberOrigin - the origin (inclusive) of each random value

  randomNumberBound - the bound (exclusive) of each random value

  Returns:

  a stream of pseudorandom double values, each with the given origin (inclusive) and bound (exclusive)

  Throws:

  IllegalArgumentException - if randomNumberOrigin is not finite, or randomNumberBound is not finite, or randomNumberOrigin is greater than or equal to randomNumberBound

  Since:

  1.8