LongSampler.java

  1. /*
  2.  * Licensed to the Apache Software Foundation (ASF) under one or more
  3.  * contributor license agreements.  See the NOTICE file distributed with
  4.  * this work for additional information regarding copyright ownership.
  5.  * The ASF licenses this file to You under the Apache License, Version 2.0
  6.  * (the "License"); you may not use this file except in compliance with
  7.  * the License.  You may obtain a copy of the License at
  8.  *
  9.  *      http://www.apache.org/licenses/LICENSE-2.0
  10.  *
  11.  * Unless required by applicable law or agreed to in writing, software
  12.  * distributed under the License is distributed on an "AS IS" BASIS,
  13.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14.  * See the License for the specific language governing permissions and
  15.  * limitations under the License.
  16.  */
  17. package org.apache.commons.rng.sampling.distribution;

  18. import java.util.stream.LongStream;

  19. /**
  20.  * Sampler that generates values of type {@code long}.
  21.  *
  22.  * @since 1.4
  23.  */
  24. public interface LongSampler {
  25.     /**
  26.      * Creates a {@code long} sample.
  27.      *
  28.      * @return a sample.
  29.      */
  30.     long sample();

  31.     /**
  32.      * Returns an effectively unlimited stream of {@code long} sample values.
  33.      *
  34.      * <p>The default implementation produces a sequential stream that repeatedly
  35.      * calls {@link #sample sample}().
  36.      *
  37.      * @return a stream of {@code long} values.
  38.      * @since 1.5
  39.      */
  40.     default LongStream samples() {
  41.         return LongStream.generate(this::sample).sequential();
  42.     }

  43.     /**
  44.      * Returns a stream producing the given {@code streamSize} number of {@code long}
  45.      * sample values.
  46.      *
  47.      * <p>The default implementation produces a sequential stream that repeatedly
  48.      * calls {@link #sample sample}(); the stream is limited to the given {@code streamSize}.
  49.      *
  50.      * @param streamSize Number of values to generate.
  51.      * @return a stream of {@code long} values.
  52.      * @since 1.5
  53.      */
  54.     default LongStream samples(long streamSize) {
  55.         return samples().limit(streamSize);
  56.     }
  57. }