com.mongodb

类 GroupCommand

java.lang.Object

com.mongodb.GroupCommand

public class GroupCommand
extends java.lang.Object

This class groups the argument for a group operation and can build the underlying command object

MongoDB documentation

Group

构造器概要

构造器

构造器和说明
GroupCommand(DBCollection collection, DBObject keys, DBObject condition, DBObject initial, java.lang.String reduce, java.lang.String finalize) Creates a new group command.
GroupCommand(DBCollection collection, java.lang.String keyf, DBObject condition, DBObject initial, java.lang.String reduce, java.lang.String finalize) Creates a new group command.

方法概要

限定符和类型	方法和说明
DBObject	toDBObject() Turns this group command into the DBObject format of the command.

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

构造器详细资料

GroupCommand

public GroupCommand(DBCollection collection,
                    DBObject keys,
                    DBObject condition,
                    DBObject initial,
                    java.lang.String reduce,
                    java.lang.String finalize)

Creates a new group command.

参数:

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.

GroupCommand

public GroupCommand(DBCollection collection,
                    java.lang.String keyf,
                    DBObject condition,
                    DBObject initial,
                    java.lang.String reduce,
                    java.lang.String finalize)

Creates a new group command.

参数:

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.

从以下版本开始:

3.1

方法详细资料

toDBObject

public DBObject toDBObject()

Turns this group command into the DBObject format of the command.

返回:

a DBObject containing the group command as a MongoDB document