org.apache.beam.sdk.io.mongodb.FindQuery.java Source code

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Here is the source code for org.apache.beam.sdk.io.mongodb.FindQuery.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.beam.sdk.io.mongodb;

import static org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions.checkArgument;

import com.google.auto.value.AutoValue;
import com.mongodb.BasicDBObject;
import com.mongodb.MongoClient;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoCursor;
import com.mongodb.client.model.Projections;
import java.util.Collections;
import java.util.List;
import javax.annotation.Nullable;
import org.apache.beam.sdk.annotations.Experimental;
import org.apache.beam.sdk.transforms.SerializableFunction;
import org.bson.BsonDocument;
import org.bson.Document;
import org.bson.conversions.Bson;

/** Builds a MongoDB FindQuery object. */
@Experimental(Experimental.Kind.SOURCE_SINK)
@AutoValue
public abstract class FindQuery implements SerializableFunction<MongoCollection<Document>, MongoCursor<Document>> {

    @Nullable
    abstract BsonDocument filters();

    abstract int limit();

    abstract List<String> projection();

    private static Builder builder() {
        return new AutoValue_FindQuery.Builder().setLimit(0).setProjection(Collections.emptyList())
                .setFilters(new BsonDocument());
    }

    abstract Builder toBuilder();

    public static FindQuery create() {
        return builder().build();
    }

    @AutoValue.Builder
    abstract static class Builder {
        abstract Builder setFilters(@Nullable BsonDocument filters);

        abstract Builder setLimit(int limit);

        abstract Builder setProjection(List<String> projection);

        abstract FindQuery build();
    }

    /** Sets the filters to find. */
    private FindQuery withFilters(BsonDocument filters) {
        return toBuilder().setFilters(filters).build();
    }

    /** Convert the Bson filters into a BsonDocument via default encoding. */
    static BsonDocument bson2BsonDocument(Bson filters) {
        return filters.toBsonDocument(BasicDBObject.class, MongoClient.getDefaultCodecRegistry());
    }

    /** Sets the filters to find. */
    public FindQuery withFilters(Bson filters) {
        return withFilters(bson2BsonDocument(filters));
    }

    /** Sets the limit of documents to find. */
    public FindQuery withLimit(int limit) {
        return toBuilder().setLimit(limit).build();
    }

    /** Sets the projection. */
    public FindQuery withProjection(List<String> projection) {
        checkArgument(projection != null, "projection can not be null");
        return toBuilder().setProjection(projection).build();
    }

    @Override
    public MongoCursor<Document> apply(MongoCollection<Document> collection) {
        return collection.find().filter(filters()).limit(limit()).projection(Projections.include(projection()))
                .iterator();
    }
}