Max (Apache Beam SDK 0.2.0-incubating API)

java.lang.Object
- org.apache.beam.sdk.transforms.Max

```
public class Max
extends Object
```
PTransforms for computing the maximum of the elements in a PCollection, or the maximum of the values associated with each key in a PCollection of KVs.
Example 1: get the maximum of a PCollection of Doubles.
```
 
 PCollection<Double> input = ...;
 PCollection<Double> max = input.apply(Max.doublesGlobally());
  
```
Example 2: calculate the maximum of the Integers associated with each unique key (which is of type String).
```
 
 PCollection<KV<String, Integer>> input = ...;
 PCollection<KV<String, Integer>> maxPerKey = input
     .apply(Max.<String>integersPerKey());
  
```

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`Max.MaxDoubleFn` A `CombineFn` that computes the maximum of a collection of `Double`s, useful as an argument to `Combine.globally(org.apache.beam.sdk.transforms.SerializableFunction<java.lang.Iterable<V>, V>)` or `Combine.perKey(org.apache.beam.sdk.transforms.SerializableFunction<java.lang.Iterable<V>, V>)`.
`static class`	`Max.MaxFn<T>` A `CombineFn` that computes the maximum of a collection of elements of type `T` using an arbitrary `Comparator`, useful as an argument to `Combine.globally(org.apache.beam.sdk.transforms.SerializableFunction<java.lang.Iterable<V>, V>)` or `Combine.perKey(org.apache.beam.sdk.transforms.SerializableFunction<java.lang.Iterable<V>, V>)`.
`static class`	`Max.MaxIntegerFn` A `CombineFn` that computes the maximum of a collection of `Integer`s, useful as an argument to `Combine.globally(org.apache.beam.sdk.transforms.SerializableFunction<java.lang.Iterable<V>, V>)` or `Combine.perKey(org.apache.beam.sdk.transforms.SerializableFunction<java.lang.Iterable<V>, V>)`.
`static class`	`Max.MaxLongFn` A `CombineFn` that computes the maximum of a collection of `Long`s, useful as an argument to `Combine.globally(org.apache.beam.sdk.transforms.SerializableFunction<java.lang.Iterable<V>, V>)` or `Combine.perKey(org.apache.beam.sdk.transforms.SerializableFunction<java.lang.Iterable<V>, V>)`.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static Combine.Globally<Double,Double>`	`doublesGlobally()` Returns a `PTransform` that takes an input `PCollection<Double>` and returns a `PCollection<Double>` whose contents is the maximum of the input `PCollection`'s elements, or `Double.NEGATIVE_INFINITY` if there are no elements.
`static <K> Combine.PerKey<K,Double,Double>`	`doublesPerKey()` Returns a `PTransform` that takes an input `PCollection<KV<K, Double>>` and returns a `PCollection<KV<K, Double>>` that contains an output element mapping each distinct key in the input `PCollection` to the maximum of the values associated with that key in the input `PCollection`.
`static <T extends Comparable<? super T>> Combine.Globally<T,T>`	`globally()` Returns a `PTransform` that takes an input `PCollection<T>` and returns a `PCollection<T>` whose contents is the maximum according to the natural ordering of `T` of the input `PCollection`'s elements, or `null` if there are no elements.
`static <T,ComparatorT extends Comparator<? super T> & Serializable> Combine.Globally<T,T>`	`globally(ComparatorT comparator)` Returns a `PTransform` that takes an input `PCollection<T>` and returns a `PCollection<T>` whose contents is the maximum of the input `PCollection`'s elements, or `null` if there are no elements.
`static Combine.Globally<Integer,Integer>`	`integersGlobally()` Returns a `PTransform` that takes an input `PCollection<Integer>` and returns a `PCollection<Integer>` whose contents is the maximum of the input `PCollection`'s elements, or `Integer.MIN_VALUE` if there are no elements.
`static <K> Combine.PerKey<K,Integer,Integer>`	`integersPerKey()` Returns a `PTransform` that takes an input `PCollection<KV<K, Integer>>` and returns a `PCollection<KV<K, Integer>>` that contains an output element mapping each distinct key in the input `PCollection` to the maximum of the values associated with that key in the input `PCollection`.
`static Combine.Globally<Long,Long>`	`longsGlobally()` Returns a `PTransform` that takes an input `PCollection<Long>` and returns a `PCollection<Long>` whose contents is the maximum of the input `PCollection`'s elements, or `Long.MIN_VALUE` if there are no elements.
`static <K> Combine.PerKey<K,Long,Long>`	`longsPerKey()` Returns a `PTransform` that takes an input `PCollection<KV<K, Long>>` and returns a `PCollection<KV<K, Long>>` that contains an output element mapping each distinct key in the input `PCollection` to the maximum of the values associated with that key in the input `PCollection`.
`static <K,T extends Comparable<? super T>> Combine.PerKey<K,T,T>`	`perKey()` Returns a `PTransform` that takes an input `PCollection<KV<K, T>>` and returns a `PCollection<KV<K, T>>` that contains an output element mapping each distinct key in the input `PCollection` to the maximum according to the natural ordering of `T` of the values associated with that key in the input `PCollection`.
`static <K,T,ComparatorT extends Comparator<? super T> & Serializable> Combine.PerKey<K,T,T>`	`perKey(ComparatorT comparator)` Returns a `PTransform` that takes an input `PCollection<KV<K, T>>` and returns a `PCollection<KV<K, T>>` that contains one output element per key mapping each to the maximum of the values associated with that key in the input `PCollection`.

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

- Method Detail
  - integersGlobally
```
public static Combine.Globally<Integer,Integer> integersGlobally()
```
    Returns a PTransform that takes an input PCollection<Integer> and returns a PCollection<Integer> whose contents is the maximum of the input PCollection's elements, or Integer.MIN_VALUE if there are no elements.
  - integersPerKey
```
public static <K> Combine.PerKey<K,Integer,Integer> integersPerKey()
```
    Returns a PTransform that takes an input PCollection<KV<K, Integer>> and returns a PCollection<KV<K, Integer>> that contains an output element mapping each distinct key in the input PCollection to the maximum of the values associated with that key in the input PCollection.
    See Combine.PerKey for how this affects timestamps and windowing.
  - longsGlobally
```
public static Combine.Globally<Long,Long> longsGlobally()
```
    Returns a PTransform that takes an input PCollection<Long> and returns a PCollection<Long> whose contents is the maximum of the input PCollection's elements, or Long.MIN_VALUE if there are no elements.
  - longsPerKey
```
public static <K> Combine.PerKey<K,Long,Long> longsPerKey()
```
    Returns a PTransform that takes an input PCollection<KV<K, Long>> and returns a PCollection<KV<K, Long>> that contains an output element mapping each distinct key in the input PCollection to the maximum of the values associated with that key in the input PCollection.
    See Combine.PerKey for how this affects timestamps and windowing.
  - doublesGlobally
```
public static Combine.Globally<Double,Double> doublesGlobally()
```
    Returns a PTransform that takes an input PCollection<Double> and returns a PCollection<Double> whose contents is the maximum of the input PCollection's elements, or Double.NEGATIVE_INFINITY if there are no elements.
  - doublesPerKey
```
public static <K> Combine.PerKey<K,Double,Double> doublesPerKey()
```
    Returns a PTransform that takes an input PCollection<KV<K, Double>> and returns a PCollection<KV<K, Double>> that contains an output element mapping each distinct key in the input PCollection to the maximum of the values associated with that key in the input PCollection.
    See Combine.PerKey for how this affects timestamps and windowing.
  - globally
```
public static <T extends Comparable<? super T>> Combine.Globally<T,T> globally()
```
    Returns a PTransform that takes an input PCollection<T> and returns a PCollection<T> whose contents is the maximum according to the natural ordering of T of the input PCollection's elements, or null if there are no elements.
  - perKey
```
public static <K,T extends Comparable<? super T>> Combine.PerKey<K,T,T> perKey()
```
    Returns a PTransform that takes an input PCollection<KV<K, T>> and returns a PCollection<KV<K, T>> that contains an output element mapping each distinct key in the input PCollection to the maximum according to the natural ordering of T of the values associated with that key in the input PCollection.
    See Combine.PerKey for how this affects timestamps and windowing.
  - globally
```
public static <T,ComparatorT extends Comparator<? super T> & Serializable> Combine.Globally<T,T> globally(ComparatorT comparator)
```
    Returns a PTransform that takes an input PCollection<T> and returns a PCollection<T> whose contents is the maximum of the input PCollection's elements, or null if there are no elements.
  - perKey
```
public static <K,T,ComparatorT extends Comparator<? super T> & Serializable> Combine.PerKey<K,T,T> perKey(ComparatorT comparator)
```
    Returns a PTransform that takes an input PCollection<KV<K, T>> and returns a PCollection<KV<K, T>> that contains one output element per key mapping each to the maximum of the values associated with that key in the input PCollection.
    See Combine.PerKey for how this affects timestamps and windowing.

Class Max

Nested Class Summary

Method Summary

Methods inherited from class java.lang.Object

Method Detail

integersGlobally

integersPerKey

longsGlobally

longsPerKey

doublesGlobally

doublesPerKey

globally

perKey

globally

perKey