1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
|
/*-
* ============LICENSE_START=======================================================
* SDC
* ================================================================================
* Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
* ================================================================================
* 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.
* ============LICENSE_END=========================================================
*/
package org.openecomp.sdc.common.util;
import java.util.ArrayList;
import java.util.List;
import java.util.Spliterator;
import java.util.Spliterators.AbstractSpliterator;
import java.util.function.Consumer;
import java.util.function.Predicate;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
/**
* Utility Class For Actions On Streams
*
* @author mshitrit
*/
public final class StreamUtils {
private StreamUtils() {
throw new UnsupportedOperationException();
}
/**
* Breaks the stream when the predicate is not met.<br>
* Does not evaluate elements after the stream breaks.<br>
* This method evaluates the stream.<br>
*
* @param stream
* @param predicate
* @return
*/
public static <T> Stream<T> takeWhilePlusOneNoEval(Stream<T> stream, Predicate<T> predicate) {
List<T> results = new ArrayList<>();
Consumer<T> listAdder = results::add;
stream.map(e -> {
listAdder.accept(e);
return e;
}).filter(e -> !predicate.test(e)).findFirst();
return results.stream();
}
public static <T> Stream<T> takeWhile(Stream<T> stream, Predicate<T> predicate) {
return StreamSupport.stream(takeWhile(stream.spliterator(), predicate), false);
}
public static <T> Stream<T> takeWhilePlusOne(Stream<T> stream, Predicate<T> predicate) {
return StreamSupport.stream(takeWhile(stream.spliterator(), new StopAfterFailPredicate<>(predicate)), false);
}
private static <T> Spliterator<T> takeWhile(Spliterator<T> splitr, Predicate<T> predicate) {
return new MySplitIterator<>(splitr, predicate);
}
public static class MySplitIterator<T> extends AbstractSpliterator<T> implements Spliterator<T> {
private boolean stillGoing = true;
private Spliterator<T> innerItr;
private Predicate<T> innerPred;
private MySplitIterator(Spliterator<T> splitItr, Predicate<T> pred) {
super(splitItr.estimateSize(), 0);
innerItr = splitItr;
innerPred = pred;
}
@Override
public boolean tryAdvance(Consumer<? super T> action) {
boolean canAdvance = true;
if (stillGoing) {
stillGoing = innerItr.tryAdvance(createConsumerWrapper(action));
} else {
canAdvance = false;
}
return canAdvance;
}
private Consumer<? super T> createConsumerWrapper(Consumer<? super T> action) {
return new Consumer<T>() {
@Override
public void accept(T t) {
stillGoing = innerPred.test(t);
if (stillGoing) {
action.accept(t);
}
}
};
}
}
public static class StopAfterFailPredicate<T> implements Predicate<T> {
private boolean hasNotFailed;
private Predicate<T> innerPredicate;
private StopAfterFailPredicate(Predicate<T> pred) {
hasNotFailed = true;
innerPredicate = pred;
}
@Override
public boolean test(T t) {
boolean isPassed;
if (hasNotFailed) {
isPassed = true;
hasNotFailed = innerPredicate.test(t);
} else {
isPassed = false;
}
return isPassed;
}
}
}
|
