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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.aliyun.openservices.eas.discovery.utils;
import java.util.Random;
/**
* RandomUtils is a wrapper that supports all possible
* {@link Random} methods via the {@link 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}.
*/
public 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 ge 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 ge 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();
}
}