/*
* Copyright (c) 2008-2014 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;
import com.mongodb.client.model.Collation;
import com.mongodb.operation.GroupOperation;
import org.bson.BsonDocumentWrapper;
import org.bson.BsonJavaScript;
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.manual reference/command/group/ Group
*/
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.
*
* @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, final String finalize) {
this(collection, keys, condition, initial, reduce, finalize, null);
}
/**
* 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, final String finalize, 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.
*
* @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.
*
* @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, final String finalize, 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.
*
* @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 DBObjectCodec codec) {
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);
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;
}
}