java.lang.Object
- dev.morphia.aggregation.experimental.expressions.AccumulatorExpressions

public final class AccumulatorExpressions
extends Object

Defines helper methods for accumulator expressions

Since:: 2.0

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static Expression`	`addToSet(Expression value)`	Returns an array of unique expression values for each group.
`static Expression`	`avg(Expression value, Expression... additional)`	Returns an average of numerical values.
`static Expression`	`first(Expression value)`	Returns a value from the first document for each group.
`static Expression`	`last(Expression value)`	Returns a value from the last document for each group.
`static Expression`	`max(Expression value)`	Returns the highest expression value for each group.
`static Expression`	`min(Expression value)`	Returns the lowest expression value for each group.
`static Push`	`push()`	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 Expression`	`push(Expression value)`	Returns an array of expression values for each group.
`static Expression`	`stdDevPop(Expression value, Expression... additional)`	Returns the population standard deviation of the input values.
`static Expression`	`stdDevSamp(Expression value, Expression... additional)`	Returns the sample standard deviation of the input values.
`static Expression`	`sum(Expression first, Expression... additional)`	Calculates and returns the sum of numeric values.

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

- Method Detail
  - sum
```
public static Expression sum(Expression first,
                             Expression... additional)
```
    Calculates and returns the sum of numeric values. $sum ignores non-numeric values.
    
    Parameters:
    
    first - the first expression to sum
    
    additional - any subsequent expressions to include in the sum
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $sum
  - addToSet
```
public static Expression addToSet(Expression value)
```
    Returns an array of unique expression values for each group. Order of the array elements is undefined.
    
    Parameters:
    
    value - the value
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $addToSet
  - avg
```
public static Expression avg(Expression value,
                             Expression... additional)
```
    Returns an average of numerical values. Ignores non-numeric values.
    
    Parameters:
    
    value - the value
    
    additional - any subsequent expressions to include in the expression
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $avg
  - first
```
public static Expression first(Expression value)
```
    Returns a value from the first document for each group. Order is only defined if the documents are in a defined order.
    
    Parameters:
    
    value - the value
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $first
  - last
```
public static Expression last(Expression value)
```
    Returns a value from the last document for each group. Order is only defined if the documents are in a defined order.
    
    Parameters:
    
    value - the value
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $last
  - max
```
public static Expression max(Expression value)
```
    Returns the highest expression value for each group.
    
    Parameters:
    
    value - the value
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $max
  - min
```
public static Expression min(Expression value)
```
    Returns the lowest expression value for each group.
    
    Parameters:
    
    value - the value
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $min
  - push
```
public static Expression push(Expression value)
```
    Returns an array of expression values for each group.
    
    Parameters:
    
    value - the value
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $push
  - push
```
public static Push push()
```
    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.
    $push is only available in the $group stage.
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $push
  - stdDevPop
```
public static Expression stdDevPop(Expression value,
                                   Expression... additional)
```
    Returns the population standard deviation of the input values.
    
    Parameters:
    
    value - the value
    
    additional - any subsequent expressions to include in the expression
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $stdDevPop
  - stdDevSamp
```
public static Expression stdDevSamp(Expression value,
                                    Expression... additional)
```
    Returns the sample standard deviation of the input values.
    
    Parameters:
    
    value - the value
    
    additional - any subsequent expressions to include in the expression
    
    Returns:
    
    the new expression
    
    MongoDB documentation
    Aggregration Expression: $stdDevSamp

Class AccumulatorExpressions

Method Summary

Methods inherited from class java.lang.Object

Method Detail

sum

addToSet

avg

first

last

max

min

push

push

stdDevPop

stdDevSamp