com.alibaba.nacos.client.naming.utils.RandomUtils Maven / Gradle / Ivy
/*
* Copyright 1999-2018 Alibaba Group Holding Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.alibaba.nacos.client.naming.utils;
import java.util.Random;
/**
* RandomUtils is a wrapper that supports all possible {@link java.util.Random} methods via the {@link
* java.lang.Math#random()} method and its system-wide Random object.
*
* @author Gary D. Gregory
* @version $Id: RandomUtils.java 906320 2010-02-04 01:41:10Z sebb $
* @since 2.0
*/
public class RandomUtils {
/**
* An instance of {@link JvmRandom}.
*/
private static final Random JVM_RANDOM = new JvmRandom();
// should be possible for JVM_RANDOM?
// public static void nextBytes(byte[]) {
// public synchronized double nextGaussian();
// }
/**
* Returns the next pseudorandom, uniformly distributed int value from the Math.random() sequence.
N.B.
* All values are >= 0.
*
* @return the random int
*/
public static int nextInt() {
return nextInt(JVM_RANDOM);
}
/**
* Returns the next pseudorandom, uniformly distributed int value from the given random
* sequence.
*
* @param random the Random sequence generator.
* @return the random int
*/
public static int nextInt(Random random) {
return random.nextInt();
}
/**
* Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified
* value (exclusive), from the Math.random() sequence.
*
* @param n the specified exclusive max-value
* @return the random int
*/
public static int nextInt(int n) {
return nextInt(JVM_RANDOM, n);
}
/**
* Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified
* value (exclusive), from the given Random sequence.
*
* @param random the Random sequence generator.
* @param n the specified exclusive max-value
* @return the random int
*/
public static int nextInt(Random random, int n) {
// check this cannot return 'n'
return random.nextInt(n);
}
/**
* Returns the next pseudorandom, uniformly distributed long value from the Math.random() sequence.
N.B.
* All values are >= 0.
*
* @return the random long
*/
public static long nextLong() {
return nextLong(JVM_RANDOM);
}
/**
* Returns the next pseudorandom, uniformly distributed long value from the given Random sequence.
*
* @param random the Random sequence generator.
* @return the random long
*/
public static long nextLong(Random random) {
return random.nextLong();
}
/**
* Returns the next pseudorandom, uniformly distributed boolean value from the Math.random() sequence.
*
* @return the random boolean
*/
public static boolean nextBoolean() {
return nextBoolean(JVM_RANDOM);
}
/**
* Returns the next pseudorandom, uniformly distributed boolean value from the given random sequence.
*
* @param random the Random sequence generator.
* @return the random boolean
*/
public static boolean nextBoolean(Random random) {
return random.nextBoolean();
}
/**
* Returns the next pseudorandom, uniformly distributed float value between 0.0 and
* 1.0
* from the Math.random() sequence.
*
* @return the random float
*/
public static float nextFloat() {
return nextFloat(JVM_RANDOM);
}
/**
* Returns the next pseudorandom, uniformly distributed float value between 0.0 and
* 1.0
* from the given Random sequence.
*
* @param random the Random sequence generator.
* @return the random float
*/
public static float nextFloat(Random random) {
return random.nextFloat();
}
/**
* Returns the next pseudorandom, uniformly distributed float value between 0.0 and
* 1.0
* from the Math.random() sequence.
*
* @return the random double
*/
public static double nextDouble() {
return nextDouble(JVM_RANDOM);
}
/**
* Returns the next pseudorandom, uniformly distributed float value between 0.0 and
* 1.0
* from the given Random sequence.
*
* @param random the Random sequence generator.
* @return the random double
*/
public static double nextDouble(Random random) {
return random.nextDouble();
}
}