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/*
 * 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.MongoNamespace;
import com.mongodb.async.AsyncBatchCursor;
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.operation.CommandOperationHelper.CommandReadTransformer;
import com.mongodb.operation.CommandOperationHelper.CommandReadTransformerAsync;
import org.bson.BsonDocument;
import org.bson.BsonJavaScript;
import org.bson.BsonString;
import org.bson.codecs.Decoder;

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.OperationHelper.LOGGER;
import static com.mongodb.operation.OperationHelper.validateCollation;

/**
 * Groups documents in a collection by the specified key and performs simple aggregation functions, such as computing counts and sums. The
 * command is analogous to a SELECT ... GROUP BY statement in SQL.
 *
 * @param  the operations result type.
 * @mongodb.driver.manual reference/command/group Group Command
 * @since 3.0
 */
@Deprecated
public class GroupOperation implements AsyncReadOperation>, ReadOperation> {
    private final MongoNamespace namespace;
    private final Decoder decoder;
    private final BsonJavaScript reduceFunction;
    private final BsonDocument initial;
    private boolean retryReads;
    private BsonDocument key;
    private BsonJavaScript keyFunction;
    private BsonDocument filter;
    private BsonJavaScript finalizeFunction;
    private Collation collation;

    /**
     * Create an operation that will perform a Group on a given collection.
     *
     * @param namespace the database and collection namespace for the operation.
     * @param reduceFunction The aggregation function that operates on the documents during the grouping operation.
     * @param initial The initial the aggregation result document.
     * @param decoder the decoder for the result documents.
     * @mongodb.driver.manual reference/command/group Group Command
     */
    public GroupOperation(final MongoNamespace namespace, final BsonJavaScript reduceFunction,
                          final BsonDocument initial, final Decoder decoder) {
        this.namespace = notNull("namespace", namespace);
        this.reduceFunction = notNull("reduceFunction", reduceFunction);
        this.initial = notNull("initial", initial);
        this.decoder = notNull("decoder", decoder);
    }

    /**
     * Gets the namespace.
     *
     * @return the namespace
     * @since 3.4
     */
    public MongoNamespace getNamespace() {
        return namespace;
    }


    /**
     * Gets the decoder used to decode the result documents.
     *
     * @return the decoder
     * @since 3.4
     */
    public Decoder getDecoder() {
        return decoder;
    }

    /**
     * Gets the document containing the field or fields to group.
     *
     * @return the document containing the field or fields to group.
     */
    public BsonDocument getKey() {
        return key;
    }

    /**
     * Sets the document containing the field or fields to group.
     *
     * @param key the document containing the field or fields to group.
     * @return this
     */
    public GroupOperation key(final BsonDocument key) {
        this.key = key;
        return this;
    }

    /**
     * Gets the function that creates a "key object" for use as the grouping key.
     *
     * @return the function that creates a "key object" for use as the grouping key.
     */
    public BsonJavaScript getKeyFunction() {
        return keyFunction;
    }

    /**
     * Sets the function that creates a "key object" for use as the grouping key.
     *
     * @param keyFunction the function that creates a "key object" for use as the grouping key.
     * @return this
     */
    public GroupOperation keyFunction(final BsonJavaScript keyFunction) {
        this.keyFunction = keyFunction;
        return this;
    }

    /**
     * Gets the initial the aggregation result document.
     *
     * @return the initial the aggregation result document.
     */
    public BsonDocument getInitial() {
        return initial;
    }

    /**
     * Gets the aggregation function that operates on the documents during the grouping operation.
     *
     * @return the aggregation function that operates on the documents during the grouping operation.
     */
    public BsonJavaScript getReduceFunction() {
        return reduceFunction;
    }

    /**
     * Gets the query filter to determine which documents in the collection to process.
     *
     * @return the query filter to determine which documents in the collection to process.
     */
    public BsonDocument getFilter() {
        return filter;
    }

    /**
     * Sets the optional query filter to determine which documents in the collection to process.
     *
     * @param filter the query filter to determine which documents in the collection to process.
     * @return this
     */
    public GroupOperation filter(final BsonDocument filter) {
        this.filter = filter;
        return this;
    }

    /**
     * Gets the function that runs each item in the result before returning the final value.
     *
     * @return the function that runs each item in the result set before returning the final value.
     */
    public BsonJavaScript getFinalizeFunction() {
        return finalizeFunction;
    }

    /**
     * Sets the function that runs each item in the result set before returning the final value.
     *
     * @param finalizeFunction the function that runs each item in the result set before returning the final value.
     * @return this
     */
    public GroupOperation finalizeFunction(final BsonJavaScript finalizeFunction) {
        this.finalizeFunction = finalizeFunction;
        return this;
    }

    /**
     * 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.

* @param collation the collation options to use * @return this * @since 3.4 * @mongodb.server.release 3.4 */ public GroupOperation collation(final Collation collation) { this.collation = collation; return this; } /** * Enables retryable reads if a read fails due to a network error. * * @param retryReads true if reads should be retried * @return this * @since 3.11 */ public GroupOperation retryReads(final boolean retryReads) { this.retryReads = retryReads; return this; } /** * Gets the value for retryable reads. The default is true. * * @return the retryable reads value * @since 3.11 */ public boolean getRetryReads() { return retryReads; } /** * Will return a cursor of Documents containing the results of the group operation. * * @param binding the binding * @return a MongoCursor of T, the results of the group operation in a form to be iterated over. */ @Override public BatchCursor execute(final ReadBinding binding) { return executeCommand(binding, namespace.getDatabaseName(), getCommandCreator(), CommandResultDocumentCodec.create(decoder, "retval"), transformer(), retryReads); } @Override public void executeAsync(final AsyncReadBinding binding, final SingleResultCallback> callback) { executeCommandAsync(binding, namespace.getDatabaseName(), getCommandCreator(), CommandResultDocumentCodec.create(decoder, "retval"), asyncTransformer(), retryReads, errorHandlingCallback(callback, LOGGER)); } private CommandCreator getCommandCreator() { return new CommandCreator() { @Override public BsonDocument create(final ServerDescription serverDescription, final ConnectionDescription connectionDescription) { validateCollation(connectionDescription, collation); return getCommand(); } }; } private BsonDocument getCommand() { BsonDocument commandDocument = new BsonDocument("ns", new BsonString(namespace.getCollectionName())); if (getKey() != null) { commandDocument.put("key", getKey()); } else if (getKeyFunction() != null) { commandDocument.put("$keyf", getKeyFunction()); } commandDocument.put("initial", getInitial()); commandDocument.put("$reduce", getReduceFunction()); if (getFinalizeFunction() != null) { commandDocument.put("finalize", getFinalizeFunction()); } if (getFilter() != null) { commandDocument.put("cond", getFilter()); } if (getCollation() != null) { commandDocument.put("collation", collation.asDocument()); } return new BsonDocument("group", commandDocument); } private CommandReadTransformer> transformer() { return new CommandReadTransformer>() { @Override public BatchCursor apply(final BsonDocument result, final ConnectionSource source, final Connection connection) { return new QueryBatchCursor(createQueryResult(result, connection.getDescription()), 0, 0, decoder, source); } }; } private CommandReadTransformerAsync> asyncTransformer() { return new CommandReadTransformerAsync>() { @Override public AsyncBatchCursor apply(final BsonDocument result, final AsyncConnectionSource source, final AsyncConnection connection) { return new AsyncSingleBatchQueryCursor(createQueryResult(result, connection.getDescription())); } }; } @SuppressWarnings("unchecked") private QueryResult createQueryResult(final BsonDocument result, final ConnectionDescription description) { return new QueryResult(namespace, BsonDocumentWrapperHelper.toList(result, "retval"), 0, description.getServerAddress()); } }




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