Package dev.morphia.aggregation.stages

Class Group

java.lang.Object

dev.morphia.aggregation.stages.Stage

dev.morphia.aggregation.stages.Group

public class Group
extends Stage

Groups input documents by the specified _id expression and for each distinct grouping, outputs a document.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Group.GroupId	Defines a group ID

Method Summary

Modifier and Type	Method	Description
Group	field(String name)	Adds a field to the group.
Group	field(String name, Object expression)	Adds a named field to the group with an expression giving the value.
static Group	group()	Creates a group stage with no ID definition
static Group	group(Group.GroupId id)	Creates a group stage with an ID definition
static Group.GroupId	id()	Creates an unnamed group ID
static Group.GroupId	id(Object name)	Creates a named group ID

Methods inherited from class java.lang.Object

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

Method Details

group

public static Group group(Group.GroupId id)

Creates a group stage with an ID definition

Parameters:

id - the group ID

Returns:

the new stage

Since:

2.2

MongoDB documentation

Aggregration Pipeline Stage: $group

group

public static Group group()

Creates a group stage with no ID definition

Returns:

the new stage

Since:

2.2

MongoDB documentation

Aggregration Pipeline Stage: $group

id

public static Group.GroupId id()

Creates an unnamed group ID

Returns:

the new groupID

id

public static Group.GroupId id(@Nullable
 Object name)

Creates a named group ID

Parameters:

name - the id name

Returns:

the new groupID

field

public Group field(String name)

Adds a field to the group.

Parameters:

name - the field name

Returns:

this

See Also:

• field(String, Object)

field

public Group field(String name,
 Object expression)

Adds a named field to the group with an expression giving the value.

Parameters:

name - the name of the field

expression - the expression giving the value

Returns:

this