Java tutorial
/* * 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.client; import com.mongodb.client.model.Collation; import com.mongodb.client.model.MapReduceAction; import com.mongodb.lang.Nullable; import org.bson.conversions.Bson; import java.util.concurrent.TimeUnit; /** * Iterable for map-reduce. * * <p>By default the {@code MapReduceIterable} returns the results inline. You can write map-reduce output to a collection by using the * {@link MapReduceIterable#collectionName(String)} method.</p> * * @param <TResult> The type of the result. * @since 3.0 */ public interface MapReduceIterable<TResult> extends MongoIterable<TResult> { /** * Aggregates documents to a collection according to the specified map-reduce function with the given options, which must specify a * non-inline result. * * @throws IllegalStateException if a collection name to write the results to has not been specified * @see #collectionName(String) * @since 3.4 */ void toCollection(); /** * Sets the collectionName for the output of the MapReduce * * <p>The default action is replace the collection if it exists, to change this use {@link #action}.</p> * * @param collectionName the name of the collection that you want the map-reduce operation to write its output. * @return this */ MapReduceIterable<TResult> collectionName(String collectionName); /** * 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 */ MapReduceIterable<TResult> finalizeFunction(@Nullable String finalizeFunction); /** * 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 */ MapReduceIterable<TResult> scope(@Nullable Bson scope); /** * 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 */ MapReduceIterable<TResult> sort(@Nullable Bson sort); /** * Sets the query 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 */ MapReduceIterable<TResult> filter(@Nullable Bson filter); /** * 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 */ MapReduceIterable<TResult> limit(int limit); /** * 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 */ MapReduceIterable<TResult> jsMode(boolean jsMode); /** * 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 */ MapReduceIterable<TResult> verbose(boolean verbose); /** * 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 */ MapReduceIterable<TResult> maxTime(long maxTime, TimeUnit timeUnit); /** * Specify the {@code MapReduceAction} to be used when writing to a collection. * * @param action an {@link MapReduceAction} to perform on the collection * @return this */ MapReduceIterable<TResult> action(MapReduceAction action); /** * Sets the name of the database to output into. * * @param databaseName the name of the database to output into. * @return this * @mongodb.driver.manual reference/command/mapReduce/#output-to-a-collection-with-an-action output with an action */ MapReduceIterable<TResult> databaseName(@Nullable String databaseName); /** * Sets if the output database is sharded * * @param sharded if the output database is sharded * @return this * @mongodb.driver.manual reference/command/mapReduce/#output-to-a-collection-with-an-action output with an action */ MapReduceIterable<TResult> sharded(boolean sharded); /** * Sets if the post-processing step will prevent MongoDB from locking the database. * * Valid only with the {@code MapReduceAction.MERGE} or {@code MapReduceAction.REDUCE} actions. * * @param nonAtomic if the post-processing step will prevent MongoDB from locking the database. * @return this * @mongodb.driver.manual reference/command/mapReduce/#output-to-a-collection-with-an-action output with an action */ MapReduceIterable<TResult> nonAtomic(boolean nonAtomic); /** * Sets the number of documents to return per batch. * * @param batchSize the batch size * @return this * @mongodb.driver.manual reference/method/cursor.batchSize/#cursor.batchSize Batch Size */ @Override MapReduceIterable<TResult> batchSize(int batchSize); /** * Sets the bypass document level validation flag. * * <p>Note: This only applies when an $out stage is specified</p>. * * @param bypassDocumentValidation If true, allows the write to opt-out of document level validation. * @return this * @since 3.2 * @mongodb.driver.manual reference/command/mapReduce mapReduce * @mongodb.server.release 3.2 */ MapReduceIterable<TResult> bypassDocumentValidation(@Nullable Boolean bypassDocumentValidation); /** * 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 */ MapReduceIterable<TResult> collation(@Nullable Collation collation); }