public class Sum
extends java.lang.Object
PTransform
s for computing the sum of the elements in a PCollection
, or the sum of
the values associated with each key in a PCollection
of KV
s.
Example 1: get the sum of a PCollection
of Double
s.
PCollection<Double> input = ...;
PCollection<Double> sum = input.apply(Sum.doublesGlobally());
Example 2: calculate the sum of the Integer
s associated with each unique key (which is
of type String
).
PCollection<KV<String, Integer>> input = ...;
PCollection<KV<String, Integer>> sumPerKey = input
.apply(Sum.<String>integersPerKey());
Modifier and Type | Method and Description |
---|---|
static Combine.Globally<java.lang.Double,java.lang.Double> |
doublesGlobally()
Returns a
PTransform that takes an input PCollection<Double> and returns a
PCollection<Double> whose contents is the sum of the input PCollection 's
elements, or 0 if there are no elements. |
static <K> Combine.PerKey<K,java.lang.Double,java.lang.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 sum of the values associated with that key in the input
PCollection . |
static Combine.Globally<java.lang.Integer,java.lang.Integer> |
integersGlobally()
Returns a
PTransform that takes an input PCollection<Integer> and returns a
PCollection<Integer> whose contents is the sum of the input PCollection 's
elements, or 0 if there are no elements. |
static <K> Combine.PerKey<K,java.lang.Integer,java.lang.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 sum of the values associated with that key
in the input PCollection . |
static Combine.Globally<java.lang.Long,java.lang.Long> |
longsGlobally()
Returns a
PTransform that takes an input PCollection<Long> and returns a PCollection<Long> whose contents is the sum of the input PCollection 's elements, or
0 if there are no elements. |
static <K> Combine.PerKey<K,java.lang.Long,java.lang.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 sum of the values associated with that key in the input
PCollection . |
static Combine.BinaryCombineDoubleFn |
ofDoubles()
A
SerializableFunction that computes the sum of an Iterable 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 Combine.BinaryCombineIntegerFn |
ofIntegers()
A
SerializableFunction that computes the sum of an Iterable 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 Combine.BinaryCombineLongFn |
ofLongs()
A
SerializableFunction that computes the sum of an Iterable 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>) . |
public static Combine.Globally<java.lang.Integer,java.lang.Integer> integersGlobally()
PTransform
that takes an input PCollection<Integer>
and returns a
PCollection<Integer>
whose contents is the sum of the input PCollection
's
elements, or 0
if there are no elements.public static <K> Combine.PerKey<K,java.lang.Integer,java.lang.Integer> integersPerKey()
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 sum of the values associated with that key
in the input PCollection
.public static Combine.Globally<java.lang.Long,java.lang.Long> longsGlobally()
PTransform
that takes an input PCollection<Long>
and returns a PCollection<Long>
whose contents is the sum of the input PCollection
's elements, or
0
if there are no elements.public static <K> Combine.PerKey<K,java.lang.Long,java.lang.Long> longsPerKey()
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 sum of the values associated with that key in the input
PCollection
.public static Combine.Globally<java.lang.Double,java.lang.Double> doublesGlobally()
PTransform
that takes an input PCollection<Double>
and returns a
PCollection<Double>
whose contents is the sum of the input PCollection
's
elements, or 0
if there are no elements.public static <K> Combine.PerKey<K,java.lang.Double,java.lang.Double> doublesPerKey()
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 sum of the values associated with that key in the input
PCollection
.public static Combine.BinaryCombineIntegerFn ofIntegers()
SerializableFunction
that computes the sum of an Iterable
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>)
.public static Combine.BinaryCombineDoubleFn ofDoubles()
SerializableFunction
that computes the sum of an Iterable
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>)
.public static Combine.BinaryCombineLongFn ofLongs()
SerializableFunction
that computes the sum of an Iterable
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>)
.