diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Aggregation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Aggregation.java index cecc8f2554..3cb57ab2c9 100644 --- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Aggregation.java +++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Aggregation.java @@ -50,6 +50,7 @@ * @author Nikolay Bogdanov * @author Gustavo de Geus * @author Jérôme Guyon + * @author James McNee * @since 1.3 */ public class Aggregation { @@ -478,6 +479,17 @@ public static SampleOperation sample(long sampleSize) { return new SampleOperation(sampleSize); } + /** + * Creates a new {@link SampleRateOperation} to select the documents from its input randomly using the provided sample rate. + * + * @param sampleRate must not be less than zero or more than one. + * @return new instance of {@link SampleRateOperation}. + * @since 3.2.4 + */ + public static SampleRateOperation sampleRate(double sampleRate) { + return new SampleRateOperation(sampleRate); + } + /** * Creates a new {@link MatchOperation} using the given {@link Criteria}. * diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SampleRateOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SampleRateOperation.java new file mode 100644 index 0000000000..3754c10d4b --- /dev/null +++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SampleRateOperation.java @@ -0,0 +1,62 @@ +/* + * Copyright 2017-2021 the original author or authors. + * + * 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 + * + * https://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 org.springframework.data.mongodb.core.aggregation; + +import org.bson.Document; +import org.springframework.util.Assert; + +/** + * Encapsulates the {@code $sampleRate}-operation. + *
+ * We recommend using the static factory method {@link Aggregation#sampleRate(double)} instead of creating instances of this + * class directly. + * + * @author James McNee + * @see MongoDB Aggregation Framework: + * $sampleRate + * @since 3.2.4 + */ +public class SampleRateOperation implements AggregationOperation { + + private final double sampleRate; + + /** + * @param sampleRate sample rate to determine number of documents to be randomly selected from the input. + */ + public SampleRateOperation(double sampleRate) { + Assert.isTrue(sampleRate >= 0, "Sample rate must be greater than zero!"); + Assert.isTrue(sampleRate <= 1, "Sample rate must not be greater than one!"); + this.sampleRate = sampleRate; + } + + /* + (non-Javadoc) + * @see org.springframework.data.mongodb.core.aggregation.BucketOperationSupport#toDocument(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext) + */ + @Override + public Document toDocument(AggregationOperationContext context) { + return new Document(getOperator(), this.sampleRate); + } + + /* + * (non-Javadoc) + * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator() + */ + @Override + public String getOperator() { + return "$sampleRate"; + } +} diff --git a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/SampleRateOperationUnitTests.java b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/SampleRateOperationUnitTests.java new file mode 100644 index 0000000000..7688f2fb91 --- /dev/null +++ b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/SampleRateOperationUnitTests.java @@ -0,0 +1,54 @@ +/* + * Copyright 2017-2021 the original author or authors. + * + * 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 + * + * https://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 org.springframework.data.mongodb.core.aggregation; + +import org.bson.Document; +import org.junit.jupiter.api.Test; + +import static org.assertj.core.api.Assertions.assertThat; +import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException; + +/** + * Unit tests for {@link SampleRateOperation}. + * + * @author James McNee + */ +public class SampleRateOperationUnitTests { + + private static final String OPERATION = "$sampleRate"; + + @Test // GH-3726 + public void shouldRejectNegativeSampleRate() { + assertThatIllegalArgumentException().isThrownBy(() -> new SampleRateOperation(-1.0)); + } + + @Test // GH-3726 + public void shouldRejectSampleRateGreaterThan1() { + assertThatIllegalArgumentException().isThrownBy(() -> new SampleRateOperation(1.1)); + } + + @Test // GH-3726 + public void rendersSampleRateOperation() { + double sampleRate = 0.34; + + SampleRateOperation sampleOperation = Aggregation.sampleRate(sampleRate); + + Document sampleOperationDocument = sampleOperation.toDocument(Aggregation.DEFAULT_CONTEXT); + + assertThat(sampleOperationDocument.get(OPERATION)).isNotNull(); + assertThat(sampleOperationDocument.get(OPERATION)).isEqualTo(sampleRate); + } +}