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
18 package org.apache.commons.rng.sampling;
19
20 import java.util.stream.Stream;
21
22 /**
23 * Sampler that generates values of a specified type.
24 *
25 * @param <T> Type of the sample.
26 * @since 1.4
27 */
28 public interface ObjectSampler<T> {
29 /**
30 * Create an object sample.
31 *
32 * @return a sample.
33 */
34 T sample();
35
36 /**
37 * Returns an effectively unlimited stream of object sample values.
38 *
39 * <p>The default implementation produces a sequential stream that repeatedly
40 * calls {@link #sample sample}().
41 *
42 * @return a stream of object values.
43 * @since 1.5
44 */
45 default Stream<T> samples() {
46 return Stream.generate(this::sample).sequential();
47 }
48
49 /**
50 * Returns a stream producing the given {@code streamSize} number of object
51 * sample values.
52 *
53 * <p>The default implementation produces a sequential stream that repeatedly
54 * calls {@link #sample sample}(); the stream is limited to the given {@code streamSize}.
55 *
56 * @param streamSize Number of values to generate.
57 * @return a stream of object values.
58 * @since 1.5
59 */
60 default Stream<T> samples(long streamSize) {
61 return samples().limit(streamSize);
62 }
63 }