Group (Morphia 1.2.1-SNAPSHOT API)

java.lang.Object
- org.mongodb.morphia.aggregation.Group

```
public final class Group
extends Object
```
Defines a group pipeline stage.

MongoDB documentation

$group

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static Accumulator`	`addToSet(String field)` Returns an array of all unique values that results from applying an expression to each document in a group of documents that share the same group by key.
`static Accumulator`	`average(String field)` Returns the average value of the numeric values that result from applying a specified expression to each document in a group of documents that share the same group by key.
`static Accumulator`	`first(String field)` Returns the value that results from applying an expression to the first document in a group of documents that share the same group by key.
`Accumulator`	`getAccumulator()`
`String`	`getName()`
`Group`	`getNested()`
`List<Projection>`	`getProjections()`
`String`	`getSourceField()`
`static Group`	`grouping(String name)` Creates a named grouping
`static Group`	`grouping(String name, Accumulator accumulator)` Creates a named grouping on a field
`static Group`	`grouping(String name, Group group)` Creates a named grouping
`static Group`	`grouping(String name, Projection... projections)` Creates a named grouping
`static Group`	`grouping(String name, String sourceField)` Creates a named grouping on a field
`static List<Group>`	`id(Group... fields)` Create a group of Groups for use as an ID
`static Accumulator`	`last(String field)` Returns the value that results from applying an expression to the last document in a group of documents that share the same group by a field.
`static Accumulator`	`max(String field)` Returns the highest value that results from applying an expression to each document in a group of documents that share the same group by key.
`static Accumulator`	`min(String field)` Returns the lowest value that results from applying an expression to each document in a group of documents that share the same group by key.
`static Accumulator`	`push(String field)` Returns an array of all values that result from applying an expression to each document in a group of documents that share the same group by key.
`static Accumulator`	`sum(String field)` Calculates and returns the sum of all the numeric values that result from applying a specified expression to each document in a group of documents that share the same group by key.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - id
```
public static List<Group> id(Group... fields)
```
    Create a group of Groups for use as an ID
    
    Parameters:
    
    fields - the Groups to group
    
    Returns:
    
    the Group
  - grouping
```
public static Group grouping(String name)
```
    Creates a named grouping
    
    Parameters:
    
    name - the field name
    
    Returns:
    
    the Group
  - grouping
```
public static Group grouping(String name,
                             Projection... projections)
```
    Creates a named grouping
    
    Parameters:
    
    name - the field name
    
    projections - the fields to create
    
    Returns:
    
    the Group
  - grouping
```
public static Group grouping(String name,
                             Group group)
```
    Creates a named grouping
    
    Parameters:
    
    name - the field name
    
    group - the fields to create
    
    Returns:
    
    the Group
  - grouping
```
public static Group grouping(String name,
                             String sourceField)
```
    Creates a named grouping on a field
    
    Parameters:
    
    name - the group name
    
    sourceField - the field name
    
    Returns:
    
    the Group
  - grouping
```
public static Group grouping(String name,
                             Accumulator accumulator)
```
    Creates a named grouping on a field
    
    Parameters:
    
    name - the group name
    
    accumulator - the Accumulator to apply to the field
    
    Returns:
    
    the Group
  - addToSet
```
public static Accumulator addToSet(String field)
```
    Returns an array of all unique values that results from applying an expression to each document in a group of documents that share the same group by key. Order of the elements in the output array is unspecified.
    
    Parameters:
    
    field - the field to process
    
    Returns:
    
    an Accumulator
    
    MongoDB documentation
    
    $addToSet
  - average
```
public static Accumulator average(String field)
```
    Returns the average value of the numeric values that result from applying a specified expression to each document in a group of documents that share the same group by key. $avg ignores non-numeric values.
    
    Parameters:
    
    field - the field to process
    
    Returns:
    
    an Accumulator
    
    MongoDB documentation
    
    $avg
  - first
```
public static Accumulator first(String field)
```
    Returns the value that results from applying an expression to the first document in a group of documents that share the same group by key. Only meaningful when documents are in a defined order.
    
    Parameters:
    
    field - the field to process
    
    Returns:
    
    an Accumulator
    
    MongoDB documentation
    
    $first
  - last
```
public static Accumulator last(String field)
```
    Returns the value that results from applying an expression to the last document in a group of documents that share the same group by a field. Only meaningful when documents are in a defined order.
    
    Parameters:
    
    field - the field to process
    
    Returns:
    
    an Accumulator
    
    MongoDB documentation
    
    $last
  - max
```
public static Accumulator max(String field)
```
    Returns the highest value that results from applying an expression to each document in a group of documents that share the same group by key.
    
    Parameters:
    
    field - the field to process
    
    Returns:
    
    an Accumulator
    
    MongoDB documentation
    
    $max
  - min
```
public static Accumulator min(String field)
```
    Returns the lowest value that results from applying an expression to each document in a group of documents that share the same group by key.
    
    Parameters:
    
    field - the field to process
    
    Returns:
    
    an Accumulator
    
    MongoDB documentation
    
    $min
  - push
```
public static Accumulator push(String field)
```
    Returns an array of all values that result from applying an expression to each document in a group of documents that share the same group by key.
    
    Parameters:
    
    field - the field to process
    
    Returns:
    
    an Accumulator
    
    MongoDB documentation
    
    $push
  - sum
```
public static Accumulator sum(String field)
```
    Calculates and returns the sum of all the numeric values that result from applying a specified expression to each document in a group of documents that share the same group by key. $sum ignores non-numeric values.
    
    Parameters:
    
    field - the field to process
    
    Returns:
    
    an Accumulator
    
    MongoDB documentation
    
    $sum
  - getAccumulator
```
public Accumulator getAccumulator()
```
    Returns:
    
    the accumulator for this Group
  - getName
```
public String getName()
```
    Returns:
    
    the name of the group
  - getSourceField
```
public String getSourceField()
```
    Returns:
    
    the source field for the group
  - getProjections
```
public List<Projection> getProjections()
```
    Returns:
    
    the projections for the group
  - getNested
```
public Group getNested()
```
    Returns:
    
    the nested group

Class Group

Method Summary

Methods inherited from class java.lang.Object

Method Detail

id

grouping

grouping

grouping

grouping

grouping

addToSet

average

first

last

max

min

push

sum

getAccumulator

getName

getSourceField

getProjections

getNested