firstBackoff * (factor ** n) where n is the iteration. If
72 | * maxBackoff is not null, the maximum backoff applied will be limited to
73 | * maxBackoff.
74 | *
75 | * If basedOnPreviousValue is true, backoff will be calculated using
76 | * prevBackoff * factor. When backoffs are combined with {@link Jitter}, this
77 | * value will be different from the actual exponential value for the iteration.
78 | *
79 | * @param firstBackoff First backoff duration
80 | * @param maxBackoff Maximum backoff duration, capped to {@link Long#MAX_VALUE} milliseconds
81 | * @param factor The multiplicand for calculating backoff
82 | * @param basedOnPreviousValue If true, calculation is based on previous value which may
83 | * be a backoff with jitter applied
84 | * @return Backoff function with exponential delay
85 | */
86 | static Backoff exponential(Duration firstBackoff, @Nullable Duration maxBackoff, int factor, boolean basedOnPreviousValue) {
87 | if (firstBackoff == null || firstBackoff.isNegative() || firstBackoff.isZero())
88 | throw new IllegalArgumentException("firstBackoff must be > 0");
89 | Duration cap = Duration.ofMillis(Long.MAX_VALUE);
90 | if (maxBackoff != null && maxBackoff.compareTo(cap) > 0) {
91 | throw new IllegalArgumentException("maxBackoff must be less than Long.MAX_VALUE milliseconds");
92 | }
93 | Duration maxBackoffInterval = maxBackoff != null && maxBackoff.compareTo(cap) < 0 ? maxBackoff : cap;
94 | if (maxBackoffInterval.compareTo(firstBackoff) < 0)
95 | throw new IllegalArgumentException("maxBackoff must be >= firstBackoff");
96 | if (!basedOnPreviousValue) {
97 | return new Backoff() {
98 | @Override
99 | public BackoffDelay apply(IterationContext context) {
100 | Duration nextBackoff;
101 | if (context.backoff() != null && context.backoff().compareTo(maxBackoffInterval) >= 0) {
102 | nextBackoff = maxBackoffInterval;
103 | }
104 | else {
105 | try {
106 | nextBackoff = firstBackoff.multipliedBy((long) Math.pow(factor, (context.iteration() - 1)));
107 | if (nextBackoff.compareTo(maxBackoffInterval) >= 0) {
108 | nextBackoff = maxBackoffInterval;
109 | }
110 | }
111 | catch (ArithmeticException e) {
112 | nextBackoff = maxBackoffInterval;
113 | }
114 | }
115 | return new BackoffDelay(firstBackoff, maxBackoffInterval, nextBackoff);
116 | }
117 |
118 | @Override
119 | public String toString() {
120 | return String.format("Backoff{exponential,min=%sms,max=%s,factor=%s,basedOnPreviousValue=false}",
121 | firstBackoff.toMillis(),
122 | maxBackoff == null ? "NONE" : maxBackoff.toMillis() + "ms",
123 | factor);
124 | }
125 | };
126 | }
127 | else {
128 | return new Backoff() {
129 | @Override
130 | public BackoffDelay apply(IterationContext context) {
131 | Duration prevBackoff = context.backoff() == null ? Duration.ZERO : context.backoff();
132 | Duration nextBackoff;
133 | if (prevBackoff.compareTo(maxBackoffInterval) >= 0) {
134 | nextBackoff = maxBackoffInterval;
135 | }
136 | else try {
137 | nextBackoff = prevBackoff.multipliedBy(factor);
138 | if (nextBackoff.compareTo(maxBackoffInterval) >= 0) {
139 | nextBackoff = maxBackoffInterval;
140 | }
141 | }
142 | catch (ArithmeticException e) {
143 | nextBackoff = maxBackoffInterval;
144 | }
145 | nextBackoff = nextBackoff.compareTo(firstBackoff) < 0 ? firstBackoff : nextBackoff;
146 | return new BackoffDelay(firstBackoff, maxBackoffInterval, nextBackoff);
147 | }
148 |
149 | @Override
150 | public String toString() {
151 | return String.format("Backoff{exponential,min=%sms,max=%s,factor=%s,basedOnPreviousValue=true}",
152 | firstBackoff.toMillis(),
153 | maxBackoff == null ? "NONE" : maxBackoff.toMillis() + "ms",
154 | factor);
155 | }
156 | };
157 | }
158 | }
159 | }
160 |
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/reactor-extra/src/main/java/reactor/retry/BackoffDelay.java:
--------------------------------------------------------------------------------
1 | /*
2 | * Copyright (c) 2017-2021 VMware Inc. or its affiliates, All Rights Reserved.
3 | *
4 | * Licensed under the Apache License, Version 2.0 (the "License");
5 | * you may not use this file except in compliance with the License.
6 | * You may obtain a copy of the License at
7 | *
8 | * https://www.apache.org/licenses/LICENSE-2.0
9 | *
10 | * Unless required by applicable law or agreed to in writing, software
11 | * distributed under the License is distributed on an "AS IS" BASIS,
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 | * See the License for the specific language governing permissions and
14 | * limitations under the License.
15 | */
16 |
17 | package reactor.retry;
18 |
19 | import java.time.Duration;
20 |
21 | public class BackoffDelay {
22 |
23 | static final BackoffDelay ZERO = new BackoffDelay(Duration.ZERO) {
24 | @Override
25 | public String toString() {
26 | return "{ZERO}";
27 | }
28 | };
29 |
30 | final Duration min;
31 | final Duration max;
32 | final Duration delay;
33 |
34 | public BackoffDelay(Duration fixedBackoff) {
35 | this(fixedBackoff, fixedBackoff, fixedBackoff);
36 | }
37 |
38 | public BackoffDelay(Duration min, Duration max, Duration delay) {
39 | this.min = min;
40 | this.max = max;
41 | this.delay = delay;
42 | }
43 |
44 | public Duration minDelay() {
45 | return min;
46 | }
47 |
48 | public Duration maxDelay() {
49 | return max;
50 | }
51 |
52 | public Duration delay() {
53 | return delay;
54 | }
55 |
56 | @Override
57 | public String toString() {
58 | if (min == max && max == delay) {
59 | return "{" + delay.toMillis() + "ms}";
60 | }
61 | else {
62 | return "{" + delay.toMillis() + "ms/" + max.toMillis() + "ms}";
63 | }
64 | }
65 | }
66 |
--------------------------------------------------------------------------------
/reactor-extra/src/main/java/reactor/retry/DefaultContext.java:
--------------------------------------------------------------------------------
1 | /*
2 | * Copyright (c) 2017-2021 VMware Inc. or its affiliates, All Rights Reserved.
3 | *
4 | * Licensed under the Apache License, Version 2.0 (the "License");
5 | * you may not use this file except in compliance with the License.
6 | * You may obtain a copy of the License at
7 | *
8 | * https://www.apache.org/licenses/LICENSE-2.0
9 | *
10 | * Unless required by applicable law or agreed to in writing, software
11 | * distributed under the License is distributed on an "AS IS" BASIS,
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 | * See the License for the specific language governing permissions and
14 | * limitations under the License.
15 | */
16 |
17 | package reactor.retry;
18 |
19 | import java.time.Duration;
20 |
21 | public class DefaultContext