Package org.apache.beam.sdk.transforms

Class Min

java.lang.Object

org.apache.beam.sdk.transforms.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 Summary

Modifier and Type	Method	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 minimum of the input PCollection's elements, or Double.POSITIVE_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 minimum 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 minimum 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 minimum 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 a single value that is the minimum of the input PCollection's elements, or Integer.MAX_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 minimum 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 minimum of the input PCollection's elements, or Long.MAX_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 minimum of the values associated with that key in the input PCollection.
static <T extends Comparable<? super T>> Combine.BinaryCombineFn<T>	naturalOrder()
static <T extends Comparable<? super T>> Combine.BinaryCombineFn<T>	naturalOrder(T identity)
static <T, ComparatorT extends Comparator<? super T> & Serializable> Combine.BinaryCombineFn<T>	of(ComparatorT comparator)	A CombineFn that computes the minimum 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 <T, ComparatorT extends Comparator<? super T> & Serializable> Combine.BinaryCombineFn<T>	of(T identity, ComparatorT comparator)	A CombineFn that computes the minimum of a collection of elements of type T using an arbitrary Comparator and an identity, 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 Combine.BinaryCombineDoubleFn	ofDoubles()	A CombineFn that computes the minimum of a collection of Doubles, 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 Combine.BinaryCombineIntegerFn	ofIntegers()	A CombineFn that computes the minimum of a collection of Integers, 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 Combine.BinaryCombineLongFn	ofLongs()	A CombineFn that computes the minimum of a collection of Longs, 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 <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.
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.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

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.

ofIntegers

public static Combine.BinaryCombineIntegerFn ofIntegers()

A CombineFn that computes the minimum of a collection of Integers, 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>).

ofLongs

public static Combine.BinaryCombineLongFn ofLongs()

A CombineFn that computes the minimum of a collection of Longs, 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>).

ofDoubles

public static Combine.BinaryCombineDoubleFn ofDoubles()

A CombineFn that computes the minimum of a collection of Doubles, 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>).

of

public static <T,
ComparatorT extends Comparator<? super T> & Serializable>
Combine.BinaryCombineFn<T> of(T identity,
 ComparatorT comparator)

A CombineFn that computes the minimum of a collection of elements of type T using an arbitrary Comparator and an identity, 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>).

Type Parameters:

T - the type of the values being compared

of

public static <T,
ComparatorT extends Comparator<? super T> & Serializable>
Combine.BinaryCombineFn<T> of(ComparatorT comparator)

A CombineFn that computes the minimum 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>).

Type Parameters:

T - the type of the values being compared

naturalOrder

public static <T extends Comparable<? super T>>
Combine.BinaryCombineFn<T> naturalOrder(T identity)

naturalOrder

public static <T extends Comparable<? super T>>
Combine.BinaryCombineFn<T> naturalOrder()

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.