| /** |
| * 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 org.apache.aurora.common.util; |
| |
| import com.google.common.base.Preconditions; |
| |
| /** |
| * A sampler that implements logic for fractional random selection. |
| * |
| * @author William Farner |
| */ |
| public class Sampler { |
| |
| private final Random rand; |
| private final double threshold; |
| |
| /** |
| * Creates a new sampler using the default system {@link Random}. |
| * |
| * @param selectPercent Percentage to randomly select, must be between 0 and 100 (inclusive). |
| */ |
| public Sampler(float selectPercent) { |
| this(selectPercent, Random.Util.newDefaultRandom()); |
| } |
| |
| /** |
| * Creates a new sampler using the provided {@link Random}. |
| * |
| * @param selectPercent Percentage to randoml select, must be between 0 and 100 (inclusive). |
| * @param rand The random utility to use for generating random numbers. |
| */ |
| public Sampler(float selectPercent, Random rand) { |
| Preconditions.checkArgument((selectPercent >= 0) && (selectPercent <= 100), |
| "Invalid selectPercent value: " + selectPercent); |
| |
| this.threshold = selectPercent / 100; |
| this.rand = Preconditions.checkNotNull(rand); |
| } |
| |
| public boolean select() { |
| return rand.nextDouble() < threshold; |
| } |
| } |