Introduce the RetryPolicy abstraction
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| Original file line number | Diff line number | Diff line change |
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| /* | ||
| * Copyright 2008-present MongoDB, Inc. | ||
| * | ||
| * 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 com.mongodb.internal.async; | ||
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| import com.mongodb.internal.async.function.RetryContext; | ||
| import com.mongodb.internal.async.function.RetryPolicy; | ||
| import com.mongodb.internal.async.function.RetryPolicy.Decision.RetryAttemptInfo; | ||
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| import java.util.function.Predicate; | ||
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| final class SimpleRetryPolicy implements RetryPolicy { | ||
| private final Predicate<Throwable> shouldRetry; | ||
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| SimpleRetryPolicy(final Predicate<Throwable> shouldRetry) { | ||
| this.shouldRetry = shouldRetry; | ||
| } | ||
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| @Override | ||
| public Decision onAttemptFailure(final RetryContext retryContext, final Throwable attemptFailedResult) { | ||
| return new Decision(attemptFailedResult, shouldRetry.test(attemptFailedResult) ? new RetryAttemptInfo() : null); | ||
| } | ||
| } |
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There was a problem hiding this comment. @vbabanin I extracted the "Rename |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,140 @@ | ||
| /* | ||
| * Copyright 2008-present MongoDB, Inc. | ||
| * | ||
| * 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 com.mongodb.internal.async.function; | ||
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| import com.mongodb.annotations.NotThreadSafe; | ||
| import com.mongodb.internal.async.MutableValue; | ||
| import com.mongodb.internal.async.SingleResultCallback; | ||
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| import java.util.function.Supplier; | ||
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| import static com.mongodb.assertions.Assertions.assertFalse; | ||
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| /** | ||
| * A stateful controller of a loop that can be used to control it, for example, | ||
| * to {@linkplain #breakAndCompleteIf(Supplier, SingleResultCallback) break} it. | ||
| * {@linkplain MutableValue} may be used by the loop to preserve state between iterations. | ||
| * <p> | ||
| * This class is not part of the public API and may be removed or changed at any time. | ||
| * | ||
| * @see AsyncCallbackLoop | ||
| */ | ||
| @NotThreadSafe | ||
| public final class LoopControl { | ||
| private int iteration; | ||
| private boolean lastIteration; | ||
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| public LoopControl() { | ||
| iteration = 0; | ||
| } | ||
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| /** | ||
| * Advances this {@link LoopControl} such that it represents the state of the immediate next iteration, if any. | ||
| * Must not be called before the {@linkplain #isFirstIteration() first iteration}, must be called before each subsequent iteration. | ||
| * | ||
| * @return {@code true} if another iteration must be executed; | ||
| * otherwise the loop was {@link #isLastIteration() broken} and {@code false} is returned. | ||
| */ | ||
| boolean advance() { | ||
| if (lastIteration) { | ||
| return false; | ||
| } else { | ||
| iteration++; | ||
| return true; | ||
| } | ||
| } | ||
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| /** | ||
| * Returns {@code true} iff the current iteration is the first one. | ||
| * | ||
| * @see #iteration() | ||
| */ | ||
| boolean isFirstIteration() { | ||
| return iteration == 0; | ||
| } | ||
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| /** | ||
| * Returns {@code true} iff {@link #breakAndCompleteIf(Supplier, SingleResultCallback)} / {@link #markAsLastIteration()} was called. | ||
| */ | ||
| boolean isLastIteration() { | ||
| return lastIteration; | ||
| } | ||
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| /** | ||
| * A 0-based iteration number. | ||
| */ | ||
| int iteration() { | ||
| return iteration; | ||
| } | ||
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| /** | ||
| * This method emulates executing the <a href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-14.html#jls-14.15">{@code break}</a> statement | ||
| * in callback-based code. If {@code true} is returned, the caller must complete the current attempt. | ||
| * <p> | ||
| * Must not be called after breaking the loop. | ||
| * | ||
| * @param predicate {@code true} iff the loop needs to be broken. | ||
| * <ul> | ||
| * <li> | ||
| * If the {@code predicate} completes abruptly, this method completes the {@code callback} with the same exception but does not break the loop;</li> | ||
| * <li> | ||
| * if the {@code predicate} is {@code true}, then this method breaks the retry loop;</li> | ||
| * <li> | ||
| * if the {@code predicate} is {@code false}, then this method does nothing. | ||
| * </ul> | ||
| * @return {@code true} iff the {@code callback} was completed, which happens iff any of the following is true: | ||
| * <ul> | ||
| * <li>the {@code predicate} completed abruptly;</li> | ||
| * <li>this method broke the loop.</li> | ||
| * </ul> | ||
| * | ||
| * @see #isLastIteration() | ||
| */ | ||
| public boolean breakAndCompleteIf(final Supplier<Boolean> predicate, final SingleResultCallback<?> callback) { | ||
| assertFalse(lastIteration); | ||
| try { | ||
| lastIteration = predicate.get(); | ||
| } catch (Throwable predicateException) { | ||
| callback.onResult(null, predicateException); | ||
| return true; | ||
| } | ||
| if (lastIteration) { | ||
| callback.onResult(null, null); | ||
| return true; | ||
| } else { | ||
| return false; | ||
| } | ||
| } | ||
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| /** | ||
| * This method is similar to {@link #breakAndCompleteIf(Supplier, SingleResultCallback)}. | ||
| * The difference is that it allows the current iteration to continue, yet no more iterations will happen. | ||
| * | ||
| * @see #isLastIteration() | ||
| */ | ||
| void markAsLastIteration() { | ||
| assertFalse(lastIteration); | ||
| lastIteration = true; | ||
| } | ||
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| @Override | ||
| public String toString() { | ||
| return "LoopControl{" | ||
| + "iteration=" + iteration | ||
| + ", lastIteration=" + lastIteration | ||
| + '}'; | ||
| } | ||
| } |
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