Min (Google Cloud Dataflow SDK 1.9.1 API)

Google Cloud Dataflow SDK for Java, version 1.9.1

com.google.cloud.dataflow.sdk.transforms

Class Min


  • public class Min
extends Object
    PTransforms for computing the minimum of the elements in a PCollection, or the minimum of the values associated with each key in a PCollection of KVs.

    Example 1: get the minimum of a PCollection of Doubles. 

     
 PCollection<Double> input = ...;
 PCollection<Double> min = input.apply(Min.doublesGlobally());

    Example 2: calculate the minimum of the Integers associated with each unique key (which is of type String). 

     
 PCollection<KV<String, Integer>> input = ...;
 PCollection<KV<String, Integer>> minPerKey = input
     .apply(Min.<String>integersPerKey());

    • 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 a single value that is the minimum of the input PCollection's elements, or Integer.MAX_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 minimum 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 minimum of the input PCollection's elements, or Long.MAX_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 minimum 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 minimum of the input PCollection's elements, or Double.POSITIVE_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 minimum 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 minimum 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 minimum 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 minimum 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 minimum of the values associated with that key in the input PCollection.

        See Combine.PerKey for how this affects timestamps and windowing.