Reducer (pregel 2.0.0-alpha02 API)

All Known Implementing Classes:

Reducer.Count, Reducer.Max, Reducer.Min, Reducer.Sum
```
public interface Reducer
```

Nested Class Summary

Nested Classes
Modifier and Type Interface Description

static class Reducer.Count

static class Reducer.Max

static class Reducer.Min

static class Reducer.Sum

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`double`	`identity()`	The identity element is used as the initial value.
`double`	`reduce(double current, double message)`	Computes a new value based on the current value and the message.

- Method Detail
  - identity
```
double identity()
```
    The identity element is used as the initial value.
  - reduce
```
double reduce(double current,
              double message)
```
    Computes a new value based on the current value and the message.