/*
 * 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;

import com.mongodb.client.model.Collation;
import com.mongodb.lang.Nullable;
import com.mongodb.operation.GroupOperation;
import org.bson.BsonDocumentWrapper;
import org.bson.BsonJavaScript;
import org.bson.codecs.Codec;

import static com.mongodb.assertions.Assertions.notNull;

This class groups the argument for a group operation and can build the underlying command object
@mongodb.driver.manualreference/command/group/ Group
Deprecated:the group command was deprecated in MongoDB 3.4
/** * This class groups the argument for a group operation and can build the underlying command object * * @mongodb.driver.manual reference/command/group/ Group * @deprecated the group command was deprecated in MongoDB 3.4 */
@Deprecated public class GroupCommand { private final String collectionName; private final DBObject keys; private final String keyf; private final DBObject condition; private final DBObject initial; private final String reduce; private final String finalize; private final Collation collation;
Creates a new group command.
Params:
  • collection – the collection from which to perform the group by operation.
  • keys – the field or fields to group.
  • condition – optional - a filter to determine which documents in the collection to process.
  • initial – the initial state of the aggregation result document.
  • reduce – a JavaScript aggregation function that operates on the documents during the grouping operation.
  • finalize – optional - a JavaScript function that runs each item in the result set before group returns the final value.
/** * Creates a new group command. * * @param collection the collection from which to perform the group by operation. * @param keys the field or fields to group. * @param condition optional - a filter to determine which documents in the collection to process. * @param initial the initial state of the aggregation result document. * @param reduce a JavaScript aggregation function that operates on the documents during the grouping operation. * @param finalize optional - a JavaScript function that runs each item in the result set before group returns the final value. */
public GroupCommand(final DBCollection collection, final DBObject keys, final DBObject condition, final DBObject initial, final String reduce, @Nullable final String finalize) { this(collection, keys, condition, initial, reduce, finalize, null); }
Creates a new group command.
Params:
  • collection – the collection from which to perform the group by operation.
  • keys – the field or fields to group.
  • condition – optional - a filter to determine which documents in the collection to process.
  • initial – the initial state of the aggregation result document.
  • reduce – a JavaScript aggregation function that operates on the documents during the grouping operation.
  • finalize – optional - a JavaScript function that runs each item in the result set before group returns the final value.
  • collation – optional - the collation options
Since:3.4
/** * Creates a new group command. * * @param collection the collection from which to perform the group by operation. * @param keys the field or fields to group. * @param condition optional - a filter to determine which documents in the collection to process. * @param initial the initial state of the aggregation result document. * @param reduce a JavaScript aggregation function that operates on the documents during the grouping operation. * @param finalize optional - a JavaScript function that runs each item in the result set before group returns the final value. * @param collation optional - the collation options * * @since 3.4 */
public GroupCommand(final DBCollection collection, final DBObject keys, final DBObject condition, final DBObject initial, final String reduce, @Nullable final String finalize, @Nullable final Collation collation) { notNull("collection", collection); this.collectionName = collection.getName(); this.keys = keys; this.condition = condition; this.initial = initial; this.reduce = reduce; this.finalize = finalize; this.keyf = null; this.collation = collation; }
Creates a new group command.
Params:
  • collection – the collection from which to perform the group by operation.
  • keyf – the function that creates a "key object" for use as the grouping key
  • condition – optional - a filter to determine which documents in the collection to process.
  • initial – the initial state of the aggregation result document.
  • reduce – a JavaScript aggregation function that operates on the documents during the grouping operation.
  • finalize – optional - a JavaScript function that runs each item in the result set before group returns the final value.
Since:3.1
/** * Creates a new group command. * * @param collection the collection from which to perform the group by operation. * @param keyf the function that creates a "key object" for use as the grouping key * @param condition optional - a filter to determine which documents in the collection to process. * @param initial the initial state of the aggregation result document. * @param reduce a JavaScript aggregation function that operates on the documents during the grouping operation. * @param finalize optional - a JavaScript function that runs each item in the result set before group returns the final value. * * @since 3.1 */
public GroupCommand(final DBCollection collection, final String keyf, final DBObject condition, final DBObject initial, final String reduce, final String finalize) { this(collection, keyf, condition, initial, reduce, finalize, null); }
Creates a new group command.
Params:
  • collection – the collection from which to perform the group by operation.
  • keyf – the function that creates a "key object" for use as the grouping key
  • condition – optional - a filter to determine which documents in the collection to process.
  • initial – the initial state of the aggregation result document.
  • reduce – a JavaScript aggregation function that operates on the documents during the grouping operation.
  • finalize – optional - a JavaScript function that runs each item in the result set before group returns the final value.
  • collation – optional - the collation options
Since:3.4
/** * Creates a new group command. * * @param collection the collection from which to perform the group by operation. * @param keyf the function that creates a "key object" for use as the grouping key * @param condition optional - a filter to determine which documents in the collection to process. * @param initial the initial state of the aggregation result document. * @param reduce a JavaScript aggregation function that operates on the documents during the grouping operation. * @param finalize optional - a JavaScript function that runs each item in the result set before group returns the final value. * @param collation optional - the collation options * * @since 3.4 */
public GroupCommand(final DBCollection collection, final String keyf, final DBObject condition, final DBObject initial, final String reduce, @Nullable final String finalize, @Nullable final Collation collation) { notNull("collection", collection); this.collectionName = collection.getName(); this.keyf = notNull("keyf", keyf); this.condition = condition; this.initial = initial; this.reduce = reduce; this.finalize = finalize; this.keys = null; this.collation = collation; }
Turns this group command into the DBObject format of the command.
Returns:a DBObject containing the group command as a MongoDB document
/** * Turns this group command into the DBObject format of the command. * * @return a DBObject containing the group command as a MongoDB document */
public DBObject toDBObject() { DBObject args = new BasicDBObject("ns", collectionName).append("cond", condition) .append("$reduce", reduce) .append("initial", initial); if (keys != null) { args.put("key", keys); } if (keyf != null) { args.put("$keyf", keyf); } if (finalize != null) { args.put("finalize", finalize); } return new BasicDBObject("group", args); } GroupOperation<DBObject> toOperation(final MongoNamespace namespace, final Codec<DBObject> codec, final boolean retryReads) { if (initial == null) { throw new IllegalArgumentException("Group command requires an initial document for the aggregate result"); } if (reduce == null) { throw new IllegalArgumentException("Group command requires a reduce function for the aggregate result"); } GroupOperation<DBObject> operation = new GroupOperation<DBObject>(namespace, new BsonJavaScript(reduce), new BsonDocumentWrapper<DBObject>(initial, codec), codec).retryReads(retryReads); if (keys != null) { operation.key(new BsonDocumentWrapper<DBObject>(keys, codec)); } if (keyf != null) { operation.keyFunction(new BsonJavaScript(keyf)); } if (condition != null) { operation.filter(new BsonDocumentWrapper<DBObject>(condition, codec)); } if (finalize != null) { operation.finalizeFunction(new BsonJavaScript(finalize)); } operation.collation(collation); return operation; } }