/*
 * 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.operation;

import com.mongodb.ExplainVerbosity;
import com.mongodb.MongoNamespace;
import com.mongodb.async.SingleResultCallback;
import com.mongodb.binding.AsyncConnectionSource;
import com.mongodb.binding.AsyncReadBinding;
import com.mongodb.binding.ConnectionSource;
import com.mongodb.binding.ReadBinding;
import com.mongodb.client.model.Collation;
import com.mongodb.connection.AsyncConnection;
import com.mongodb.connection.Connection;
import com.mongodb.connection.ConnectionDescription;
import com.mongodb.connection.QueryResult;
import com.mongodb.connection.ServerDescription;
import com.mongodb.internal.connection.NoOpSessionContext;
import com.mongodb.operation.CommandOperationHelper.CommandReadTransformer;
import com.mongodb.operation.CommandOperationHelper.CommandReadTransformerAsync;
import com.mongodb.session.SessionContext;
import org.bson.BsonBoolean;
import org.bson.BsonDocument;
import org.bson.BsonInt32;
import org.bson.BsonJavaScript;
import org.bson.BsonNull;
import org.bson.BsonString;
import org.bson.BsonValue;
import org.bson.codecs.BsonDocumentCodec;
import org.bson.codecs.Decoder;

import java.util.concurrent.TimeUnit;

import static com.mongodb.assertions.Assertions.notNull;
import static com.mongodb.internal.async.ErrorHandlingResultCallback.errorHandlingCallback;
import static com.mongodb.operation.CommandOperationHelper.CommandCreator;
import static com.mongodb.operation.CommandOperationHelper.executeCommand;
import static com.mongodb.operation.CommandOperationHelper.executeCommandAsync;
import static com.mongodb.operation.DocumentHelper.putIfNotZero;
import static com.mongodb.operation.DocumentHelper.putIfTrue;
import static com.mongodb.operation.ExplainHelper.asExplainCommand;
import static com.mongodb.operation.OperationHelper.LOGGER;
import static com.mongodb.operation.OperationHelper.validateReadConcernAndCollation;
import static com.mongodb.operation.OperationReadConcernHelper.appendReadConcernToCommand;
import static java.util.concurrent.TimeUnit.MILLISECONDS;

Operation that runs a Map Reduce against a MongoDB instance. This operation only supports "inline" results, i.e. the results will be returned as a result of running this operation.

To run a map reduce operation into a given collection, use MapReduceToCollectionOperation.

Type parameters:
  • <T> – the operations result type.
@mongodb.driver.manualreference/command/mapReduce/ mapReduce
@mongodb.driver.manualcore/map-reduce Map-Reduce
Since:3.0
/** * <p>Operation that runs a Map Reduce against a MongoDB instance. This operation only supports "inline" results, i.e. the results will be * returned as a result of running this operation.</p> * * <p>To run a map reduce operation into a given collection, use {@code MapReduceToCollectionOperation}.</p> * * @param <T> the operations result type. * @mongodb.driver.manual reference/command/mapReduce/ mapReduce * @mongodb.driver.manual core/map-reduce Map-Reduce * @since 3.0 */
@Deprecated public class MapReduceWithInlineResultsOperation<T> implements AsyncReadOperation<MapReduceAsyncBatchCursor<T>>, ReadOperation<MapReduceBatchCursor<T>> { private final MongoNamespace namespace; private final BsonJavaScript mapFunction; private final BsonJavaScript reduceFunction; private final Decoder<T> decoder; private BsonJavaScript finalizeFunction; private BsonDocument scope; private BsonDocument filter; private BsonDocument sort; private int limit; private boolean jsMode; private boolean verbose; private long maxTimeMS; private Collation collation;
Construct a MapReduceOperation with all the criteria it needs to execute.
Params:
  • namespace – the database and collection namespace for the operation.
  • mapFunction – a JavaScript function that associates or "maps" a value with a key and emits the key and value pair.
  • reduceFunction – a JavaScript function that "reduces" to a single object all the values associated with a particular key.
  • decoder – the decoder for the result documents.
@mongodb.driver.manualreference/command/mapReduce/ mapReduce
/** * Construct a MapReduceOperation with all the criteria it needs to execute. * * @param namespace the database and collection namespace for the operation. * @param mapFunction a JavaScript function that associates or "maps" a value with a key and emits the key and value pair. * @param reduceFunction a JavaScript function that "reduces" to a single object all the values associated with a particular key. * @param decoder the decoder for the result documents. * @mongodb.driver.manual reference/command/mapReduce/ mapReduce */
public MapReduceWithInlineResultsOperation(final MongoNamespace namespace, final BsonJavaScript mapFunction, final BsonJavaScript reduceFunction, final Decoder<T> decoder) { this.namespace = notNull("namespace", namespace); this.mapFunction = notNull("mapFunction", mapFunction); this.reduceFunction = notNull("reduceFunction", reduceFunction); this.decoder = notNull("decoder", decoder); }
Gets the namespace.
Returns:the namespace
Since:3.4
/** * Gets the namespace. * * @return the namespace * @since 3.4 */
public MongoNamespace getNamespace() { return namespace; }
Gets the decoder used to decode the result documents.
Returns:the decoder
Since:3.4
/** * Gets the decoder used to decode the result documents. * * @return the decoder * @since 3.4 */
public Decoder<T> getDecoder() { return decoder; }
Gets the JavaScript function that associates or "maps" a value with a key and emits the key and value pair.
Returns:the JavaScript function that associates or "maps" a value with a key and emits the key and value pair.
/** * Gets the JavaScript function that associates or "maps" a value with a key and emits the key and value pair. * * @return the JavaScript function that associates or "maps" a value with a key and emits the key and value pair. */
public BsonJavaScript getMapFunction() { return mapFunction; }
Gets the JavaScript function that "reduces" to a single object all the values associated with a particular key.
Returns:the JavaScript function that "reduces" to a single object all the values associated with a particular key.
/** * Gets the JavaScript function that "reduces" to a single object all the values associated with a particular key. * * @return the JavaScript function that "reduces" to a single object all the values associated with a particular key. */
public BsonJavaScript getReduceFunction() { return reduceFunction; }
Gets the JavaScript function that follows the reduce method and modifies the output. Default is null
Returns:the JavaScript function that follows the reduce method and modifies the output.
@mongodb.driver.manualreference/command/mapReduce/#mapreduce-finalize-cmd Requirements for the finalize Function
/** * Gets the JavaScript function that follows the reduce method and modifies the output. Default is null * * @return the JavaScript function that follows the reduce method and modifies the output. * @mongodb.driver.manual reference/command/mapReduce/#mapreduce-finalize-cmd Requirements for the finalize Function */
public BsonJavaScript getFinalizeFunction() { return finalizeFunction; }
Sets the JavaScript function that follows the reduce method and modifies the output.
Params:
  • finalizeFunction – the JavaScript function that follows the reduce method and modifies the output.
Returns:this
@mongodb.driver.manualreference/command/mapReduce/#mapreduce-finalize-cmd Requirements for the finalize Function
/** * Sets the JavaScript function that follows the reduce method and modifies the output. * * @param finalizeFunction the JavaScript function that follows the reduce method and modifies the output. * @return this * @mongodb.driver.manual reference/command/mapReduce/#mapreduce-finalize-cmd Requirements for the finalize Function */
public MapReduceWithInlineResultsOperation<T> finalizeFunction(final BsonJavaScript finalizeFunction) { this.finalizeFunction = finalizeFunction; return this; }
Gets the global variables that are accessible in the map, reduce and finalize functions.
Returns:the global variables that are accessible in the map, reduce and finalize functions.
@mongodb.driver.manualreference/command/mapReduce Scope
/** * Gets the global variables that are accessible in the map, reduce and finalize functions. * * @return the global variables that are accessible in the map, reduce and finalize functions. * @mongodb.driver.manual reference/command/mapReduce Scope */
public BsonDocument getScope() { return scope; }
Sets the global variables that are accessible in the map, reduce and finalize functions.
Params:
  • scope – the global variables that are accessible in the map, reduce and finalize functions.
Returns:this
@mongodb.driver.manualreference/command/mapReduce mapReduce
/** * Sets the global variables that are accessible in the map, reduce and finalize functions. * * @param scope the global variables that are accessible in the map, reduce and finalize functions. * @return this * @mongodb.driver.manual reference/command/mapReduce mapReduce */
public MapReduceWithInlineResultsOperation<T> scope(final BsonDocument scope) { this.scope = scope; return this; }
Gets the query filter.
Returns:the query filter
@mongodb.driver.manualreference/method/db.collection.find/ Filter
/** * Gets the query filter. * * @return the query filter * @mongodb.driver.manual reference/method/db.collection.find/ Filter */
public BsonDocument getFilter() { return filter; }
Sets the filter to apply to the query.
Params:
  • filter – the filter to apply to the query.
Returns:this
@mongodb.driver.manualreference/method/db.collection.find/ Filter
/** * Sets the filter to apply to the query. * * @param filter the filter to apply to the query. * @return this * @mongodb.driver.manual reference/method/db.collection.find/ Filter */
public MapReduceWithInlineResultsOperation<T> filter(final BsonDocument filter) { this.filter = filter; return this; }
Gets the sort criteria to apply to the query. The default is null, which means that the documents will be returned in an undefined order.
Returns:a document describing the sort criteria
@mongodb.driver.manualreference/method/cursor.sort/ Sort
/** * Gets the sort criteria to apply to the query. The default is null, which means that the documents will be returned in an undefined * order. * * @return a document describing the sort criteria * @mongodb.driver.manual reference/method/cursor.sort/ Sort */
public BsonDocument getSort() { return sort; }
Sets the sort criteria to apply to the query.
Params:
  • sort – the sort criteria, which may be null.
Returns:this
@mongodb.driver.manualreference/method/cursor.sort/ Sort
/** * Sets the sort criteria to apply to the query. * * @param sort the sort criteria, which may be null. * @return this * @mongodb.driver.manual reference/method/cursor.sort/ Sort */
public MapReduceWithInlineResultsOperation<T> sort(final BsonDocument sort) { this.sort = sort; return this; }
Gets the limit to apply. The default is null.
Returns:the limit
@mongodb.driver.manualreference/method/cursor.limit/#cursor.limit Limit
/** * Gets the limit to apply. The default is null. * * @return the limit * @mongodb.driver.manual reference/method/cursor.limit/#cursor.limit Limit */
public int getLimit() { return limit; }
Sets the limit to apply.
Params:
  • limit – the limit, which may be null
Returns:this
@mongodb.driver.manualreference/method/cursor.limit/#cursor.limit Limit
/** * Sets the limit to apply. * * @param limit the limit, which may be null * @return this * @mongodb.driver.manual reference/method/cursor.limit/#cursor.limit Limit */
public MapReduceWithInlineResultsOperation<T> limit(final int limit) { this.limit = limit; return this; }
Gets the flag that specifies whether to convert intermediate data into BSON format between the execution of the map and reduce functions. Defaults to false.
Returns:jsMode
@mongodb.driver.manualreference/command/mapReduce mapReduce
/** * Gets the flag that specifies whether to convert intermediate data into BSON format between the execution of the map and reduce * functions. Defaults to false. * * @return jsMode * @mongodb.driver.manual reference/command/mapReduce mapReduce */
public boolean isJsMode() { return jsMode; }
Sets the flag that specifies whether to convert intermediate data into BSON format between the execution of the map and reduce functions. Defaults to false.
Params:
  • jsMode – the flag that specifies whether to convert intermediate data into BSON format between the execution of the map and reduce functions
Returns:jsMode
@mongodb.driver.manualreference/command/mapReduce mapReduce
/** * Sets the flag that specifies whether to convert intermediate data into BSON format between the execution of the map and reduce * functions. Defaults to false. * * @param jsMode the flag that specifies whether to convert intermediate data into BSON format between the execution of the map and * reduce functions * @return jsMode * @mongodb.driver.manual reference/command/mapReduce mapReduce */
public MapReduceWithInlineResultsOperation<T> jsMode(final boolean jsMode) { this.jsMode = jsMode; return this; }
Gets whether to include the timing information in the result information. Defaults to true.
Returns:whether to include the timing information in the result information
/** * Gets whether to include the timing information in the result information. Defaults to true. * * @return whether to include the timing information in the result information */
public boolean isVerbose() { return verbose; }
Sets whether to include the timing information in the result information.
Params:
  • verbose – whether to include the timing information in the result information.
Returns:this
/** * Sets whether to include the timing information in the result information. * * @param verbose whether to include the timing information in the result information. * @return this */
public MapReduceWithInlineResultsOperation<T> verbose(final boolean verbose) { this.verbose = verbose; return this; }
Returns the collation options
Returns:the collation options
Since:3.4
@mongodb.server.release3.4
/** * Returns the collation options * * @return the collation options * @since 3.4 * @mongodb.server.release 3.4 */
public Collation getCollation() { return collation; }
Sets the collation options

A null value represents the server default.

Params:
  • collation – the collation options to use
Returns:this
Since:3.4
@mongodb.server.release3.4
/** * Sets the collation options * * <p>A null value represents the server default.</p> * @param collation the collation options to use * @return this * @since 3.4 * @mongodb.server.release 3.4 */
public MapReduceWithInlineResultsOperation<T> collation(final Collation collation) { this.collation = collation; return this; }
Gets the maximum execution time on the server for this operation. The default is 0, which places no limit on the execution time.
Params:
  • timeUnit – the time unit to return the result in
Returns:the maximum execution time in the given time unit
@mongodb.driver.manualreference/method/cursor.maxTimeMS/#cursor.maxTimeMS Max Time
/** * Gets the maximum execution time on the server for this operation. The default is 0, which places no limit on the execution time. * * @param timeUnit the time unit to return the result in * @return the maximum execution time in the given time unit * @mongodb.driver.manual reference/method/cursor.maxTimeMS/#cursor.maxTimeMS Max Time */
public long getMaxTime(final TimeUnit timeUnit) { notNull("timeUnit", timeUnit); return timeUnit.convert(maxTimeMS, TimeUnit.MILLISECONDS); }
Sets the maximum execution time on the server for this operation.
Params:
  • maxTime – the max time
  • timeUnit – the time unit, which may not be null
Returns:this
@mongodb.driver.manualreference/method/cursor.maxTimeMS/#cursor.maxTimeMS Max Time
/** * Sets the maximum execution time on the server for this operation. * * @param maxTime the max time * @param timeUnit the time unit, which may not be null * @return this * @mongodb.driver.manual reference/method/cursor.maxTimeMS/#cursor.maxTimeMS Max Time */
public MapReduceWithInlineResultsOperation<T> maxTime(final long maxTime, final TimeUnit timeUnit) { notNull("timeUnit", timeUnit); this.maxTimeMS = TimeUnit.MILLISECONDS.convert(maxTime, timeUnit); return this; }
Executing this will return a cursor with your results and the statistics in.
Params:
  • binding – the binding
Returns:a MapReduceCursor that can be iterated over to find all the results of the Map Reduce operation.
/** * Executing this will return a cursor with your results and the statistics in. * * @param binding the binding * @return a MapReduceCursor that can be iterated over to find all the results of the Map Reduce operation. */
@Override @SuppressWarnings("unchecked") public MapReduceBatchCursor<T> execute(final ReadBinding binding) { return executeCommand(binding, namespace.getDatabaseName(), getCommandCreator(binding.getSessionContext()), CommandResultDocumentCodec.create(decoder, "results"), transformer(), false); } @Override public void executeAsync(final AsyncReadBinding binding, final SingleResultCallback<MapReduceAsyncBatchCursor<T>> callback) { SingleResultCallback<MapReduceAsyncBatchCursor<T>> errHandlingCallback = errorHandlingCallback(callback, LOGGER); executeCommandAsync(binding, namespace.getDatabaseName(), getCommandCreator(binding.getSessionContext()), CommandResultDocumentCodec.create(decoder, "results"), asyncTransformer(), false, errHandlingCallback); }
Gets an operation whose execution explains this operation.
Params:
  • explainVerbosity – the explain verbosity
Returns:a read operation that when executed will explain this operation
/** * Gets an operation whose execution explains this operation. * * @param explainVerbosity the explain verbosity * @return a read operation that when executed will explain this operation */
public ReadOperation<BsonDocument> asExplainableOperation(final ExplainVerbosity explainVerbosity) { return createExplainableOperation(explainVerbosity); }
Gets an operation whose execution explains this operation.
Params:
  • explainVerbosity – the explain verbosity
Returns:a read operation that when executed will explain this operation
/** * Gets an operation whose execution explains this operation. * * @param explainVerbosity the explain verbosity * @return a read operation that when executed will explain this operation */
public AsyncReadOperation<BsonDocument> asExplainableOperationAsync(final ExplainVerbosity explainVerbosity) { return createExplainableOperation(explainVerbosity); } private CommandReadOperation<BsonDocument> createExplainableOperation(final ExplainVerbosity explainVerbosity) { return new CommandReadOperation<BsonDocument>(namespace.getDatabaseName(), asExplainCommand(getCommand(NoOpSessionContext.INSTANCE), explainVerbosity), new BsonDocumentCodec()); } private CommandReadTransformer<BsonDocument, MapReduceBatchCursor<T>> transformer() { return new CommandReadTransformer<BsonDocument, MapReduceBatchCursor<T>>() { @Override public MapReduceBatchCursor<T> apply(final BsonDocument result, final ConnectionSource source, final Connection connection) { return new MapReduceInlineResultsCursor<T>(createQueryResult(result, connection.getDescription()), decoder, source, MapReduceHelper.createStatistics(result)); } }; } private CommandReadTransformerAsync<BsonDocument, MapReduceAsyncBatchCursor<T>> asyncTransformer() { return new CommandReadTransformerAsync<BsonDocument, MapReduceAsyncBatchCursor<T>>() { @Override public MapReduceAsyncBatchCursor<T> apply(final BsonDocument result, final AsyncConnectionSource source, final AsyncConnection connection) { return new MapReduceInlineResultsAsyncCursor<T>(createQueryResult(result, connection.getDescription()), MapReduceHelper.createStatistics(result)); } }; } private CommandCreator getCommandCreator(final SessionContext sessionContext) { return new CommandCreator() { @Override public BsonDocument create(final ServerDescription serverDescription, final ConnectionDescription connectionDescription) { validateReadConcernAndCollation(connectionDescription, sessionContext.getReadConcern(), collation); return getCommand(sessionContext); } }; } private BsonDocument getCommand(final SessionContext sessionContext) { BsonDocument commandDocument = new BsonDocument("mapreduce", new BsonString(namespace.getCollectionName())) .append("map", getMapFunction()) .append("reduce", getReduceFunction()) .append("out", new BsonDocument("inline", new BsonInt32(1))) .append("query", asValueOrNull(getFilter())) .append("sort", asValueOrNull(getSort())) .append("finalize", asValueOrNull(getFinalizeFunction())) .append("scope", asValueOrNull(getScope())) .append("verbose", BsonBoolean.valueOf(isVerbose())); appendReadConcernToCommand(sessionContext, commandDocument); putIfNotZero(commandDocument, "limit", getLimit()); putIfNotZero(commandDocument, "maxTimeMS", getMaxTime(MILLISECONDS)); putIfTrue(commandDocument, "jsMode", isJsMode()); if (collation != null) { commandDocument.put("collation", collation.asDocument()); } return commandDocument; } @SuppressWarnings("unchecked") private QueryResult<T> createQueryResult(final BsonDocument result, final ConnectionDescription description) { return new QueryResult<T>(namespace, BsonDocumentWrapperHelper.<T>toList(result, "results"), 0, description.getServerAddress()); } private static BsonValue asValueOrNull(final BsonValue value) { return value == null ? BsonNull.VALUE : value; } }