core/src/main/java/org/apache/accumulo/testing/core/stress/RandomWithinRange.java

/*
 * 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 org.apache.accumulo.test.stress.random;

import static com.google.common.base.Preconditions.checkArgument;

import java.util.Random;

/**
 * Class that returns positive integers between some minimum and maximum.
 *
 */
public class RandomWithinRange {
  private final Random random;
  private final int min, max;

  public RandomWithinRange(int seed, int min, int max) {
    this(new Random(seed), min, max);
  }

  public RandomWithinRange(Random random, int min, int max) {
    checkArgument(min > 0, "Min must be positive.");
    checkArgument(max >= min, "Max must be greater than or equal to min.");
    this.random = random;
    this.min = min;
    this.max = max;
  }

  public int next() {
    if (min == max) {
      return min;
    } else {
      // we pick a random number that's between 0 and (max - min), then add
      // min as an offset to get a random number that's [min, max)
      return random.nextInt(max - min) + min;
    }
  }

  public byte[] next_bytes() {
    byte[] b = new byte[next()];
    random.nextBytes(b);
    return b;
  }
}