Google Cloud Dataflow SDK for Java, version 1.9.1

Class Max

• ```public class Max
extends Object```
`PTransform`s for computing the maximum of the elements in a `PCollection`, or the maximum of the values associated with each key in a `PCollection` of `KV`s.

Example 1: get the maximum of a `PCollection` of `Double`s.

``` ```
PCollection<Double> input = ...;
PCollection<Double> max = input.apply(Max.doublesGlobally());
``` ```

Example 2: calculate the maximum of the `Integer`s 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());
``` ```

• Method Summary

All 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.

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