JAVA-2673 AggregateToCollectionThenFindOperation casting code smell #1950
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,78 @@ | ||
| /* | ||
| * 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. | ||
| */ | ||
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| package com.mongodb.internal.operation; | ||
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| import com.mongodb.MongoNamespace; | ||
| import com.mongodb.internal.async.AsyncBatchCursor; | ||
| import com.mongodb.internal.async.SingleResultCallback; | ||
| import com.mongodb.internal.binding.AsyncReadWriteBinding; | ||
| import com.mongodb.internal.binding.ReadWriteBinding; | ||
| import com.mongodb.internal.connection.OperationContext; | ||
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| /** | ||
| * A {@link WriteThenReadOperationCursor} that performs a {@link WriteOperation} returning | ||
| * {@code Void} followed by a {@link ReadOperationCursor}, using a single read-write | ||
| * binding for both phases. | ||
| * | ||
| * <p>This class is not part of the public API and may be removed or changed at any time</p> | ||
| */ | ||
| public final class VoidWriteOperationThenCursorReadOperation<T> implements WriteThenReadOperationCursor<T> { | ||
| private final WriteOperation<Void> writeOperation; | ||
| private final ReadOperationCursor<T> cursorReadOperation; | ||
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| public VoidWriteOperationThenCursorReadOperation(final WriteOperation<Void> writeOperation, | ||
| final ReadOperationCursor<T> cursorReadOperation) { | ||
| this.writeOperation = writeOperation; | ||
| this.cursorReadOperation = cursorReadOperation; | ||
| } | ||
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| public WriteOperation<Void> getWriteOperation() { | ||
| return writeOperation; | ||
| } | ||
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| public ReadOperationCursor<T> getCursorReadOperation() { | ||
| return cursorReadOperation; | ||
| } | ||
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| @Override | ||
| public String getCommandName() { | ||
| return writeOperation.getCommandName(); | ||
| } | ||
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| @Override | ||
| public MongoNamespace getNamespace() { | ||
| return writeOperation.getNamespace(); | ||
| } | ||
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| @Override | ||
| public BatchCursor<T> execute(final ReadWriteBinding binding, final OperationContext operationContext) { | ||
| writeOperation.execute(binding, operationContext); | ||
| return cursorReadOperation.execute(binding, operationContext); | ||
| } | ||
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| @Override | ||
| public void executeAsync(final AsyncReadWriteBinding binding, final OperationContext operationContext, | ||
| final SingleResultCallback<AsyncBatchCursor<T>> callback) { | ||
| writeOperation.executeAsync(binding, operationContext, (result, t) -> { | ||
| if (t != null) { | ||
| callback.onResult(null, t); | ||
| } else { | ||
| cursorReadOperation.executeAsync(binding, operationContext, callback); | ||
| } | ||
| }); | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,68 @@ | ||
| /* | ||
| * 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. | ||
| */ | ||
|
|
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| package com.mongodb.internal.operation; | ||
|
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| import com.mongodb.MongoNamespace; | ||
| import com.mongodb.internal.async.AsyncBatchCursor; | ||
| import com.mongodb.internal.async.SingleResultCallback; | ||
| import com.mongodb.internal.binding.AsyncReadWriteBinding; | ||
| import com.mongodb.internal.binding.ReadWriteBinding; | ||
| import com.mongodb.internal.connection.OperationContext; | ||
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| /** | ||
| * An operation that performs a write followed by a read that returns a cursor, using a | ||
| * single read-write binding for both phases. | ||
| * | ||
| * <p>Having a dedicated interface lets the executor hand the operation a binding that is | ||
| * both a {@link ReadWriteBinding} and an {@link AsyncReadWriteBinding}, avoiding the | ||
| * narrowing cast from a read-only binding that would otherwise be required. | ||
| * | ||
| * <p>This class is not part of the public API and may be removed or changed at any time</p> | ||
| */ | ||
| public interface WriteThenReadOperationCursor<T> { | ||
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| /** | ||
| * @return the command name of the write phase of this operation (e.g. "mapReduce", "aggregate") | ||
| */ | ||
| String getCommandName(); | ||
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| /** | ||
| * @return the namespace the write phase targets | ||
| */ | ||
| MongoNamespace getNamespace(); | ||
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| /** | ||
| * Executes the write phase followed by the read phase, returning a {@link BatchCursor} | ||
| * over the results of the read. | ||
| * | ||
| * @param binding the read-write binding used by both phases | ||
| * @param operationContext the operation context to use | ||
| * @return the batch cursor produced by the read phase | ||
| */ | ||
| BatchCursor<T> execute(ReadWriteBinding binding, OperationContext operationContext); | ||
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| /** | ||
| * Executes the write phase followed by the read phase, yielding an {@link AsyncBatchCursor} | ||
| * over the results of the read. | ||
| * | ||
| * @param binding the read-write binding used by both phases | ||
| * @param operationContext the operation context to use | ||
| * @param callback receives the {@link AsyncBatchCursor} on success, or the failure of either phase | ||
| */ | ||
| void executeAsync(AsyncReadWriteBinding binding, OperationContext operationContext, | ||
| SingleResultCallback<AsyncBatchCursor<T>> callback); | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
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@@ -34,12 +34,14 @@ | |
| import com.mongodb.internal.operation.Operations; | ||
| import com.mongodb.internal.operation.ReadOperation; | ||
| import com.mongodb.internal.operation.ReadOperationCursor; | ||
| import com.mongodb.internal.operation.VoidWriteOperationThenCursorReadOperation; | ||
| import com.mongodb.internal.operation.WriteOperation; | ||
| import com.mongodb.lang.Nullable; | ||
| import com.mongodb.reactivestreams.client.ClientSession; | ||
| import org.bson.BsonDocument; | ||
| import org.bson.conversions.Bson; | ||
| import org.reactivestreams.Publisher; | ||
| import reactor.core.publisher.Mono; | ||
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| import java.util.concurrent.TimeUnit; | ||
| import java.util.function.Function; | ||
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@@ -201,10 +203,46 @@ public ReadOperationCursor<T> asReadOperation(final int initialBatchSize) { | |
| if (inline) { | ||
| // initialBatchSize is ignored for map reduce operations. | ||
| return createMapReduceInlineOperation(); | ||
| } | ||
| throw new IllegalStateException("Non-inline map-reduce uses the write-then-read path; " | ||
| + "asReadOperation must not be called."); | ||
| } | ||
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| @Override | ||
| public Mono<BatchCursor<T>> batchCursor(final int initialBatchSize) { | ||
| if (inline) { | ||
| return super.batchCursor(initialBatchSize); | ||
| } | ||
| return writeThenReadBatchCursor(initialBatchSize); | ||
| } | ||
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| @Override | ||
| public Publisher<T> first() { | ||
| if (inline) { | ||
| return super.first(); | ||
| } | ||
| return writeThenReadBatchCursor(1) | ||
|
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| .flatMap(batchCursor -> { | ||
| batchCursor.setBatchSize(1); | ||
| return Mono.from(batchCursor.next()) | ||
| .doOnTerminate(batchCursor::close) | ||
| .flatMap(results -> { | ||
| if (results == null || results.isEmpty()) { | ||
| return Mono.empty(); | ||
| } | ||
| return Mono.fromCallable(() -> results.get(0)); | ||
| }); | ||
| }); | ||
| } | ||
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| private Mono<BatchCursor<T>> writeThenReadBatchCursor(final int initialBatchSize) { | ||
| return getMongoOperationPublisher() | ||
| .createWriteThenReadOperationMono( | ||
| operations -> operations.createTimeoutSettings(maxTimeMS), | ||
| () -> new VoidWriteOperationThenCursorReadOperation<>(createMapReduceToCollectionOperation(), | ||
| createFindOperation(initialBatchSize)), | ||
| getClientSession()) | ||
| .map(BatchCursor::new); | ||
| } | ||
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| private WrappedMapReduceReadOperation<T> createMapReduceInlineOperation() { | ||
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Added a unit test here