Package org.apache.beam.sdk.transforms
Class KvSwap<K,V>
- java.lang.Object
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- org.apache.beam.sdk.transforms.PTransform<PCollection<KV<K,V>>,PCollection<KV<V,K>>>
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- org.apache.beam.sdk.transforms.KvSwap<K,V>
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- Type Parameters:
K
- the type of the keys in the inputPCollection
and the values in the outputPCollection
V
- the type of the values in the inputPCollection
and the keys in the outputPCollection
- All Implemented Interfaces:
java.io.Serializable
,HasDisplayData
public class KvSwap<K,V> extends PTransform<PCollection<KV<K,V>>,PCollection<KV<V,K>>>
KvSwap<K, V>
takes aPCollection<KV<K, V>>
and returns aPCollection<KV<V, K>>
, where all the keys and values have been swapped.Example of use:
PCollection<String, Long> wordsToCounts = ...; PCollection<Long, String> countsToWords = wordToCounts.apply(KvSwap.<String, Long>create());
Each output element has the same timestamp and is in the same windows as its corresponding input element, and the output
PCollection
has the sameWindowFn
associated with it as the input.- See Also:
- Serialized Form
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Field Summary
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Fields inherited from class org.apache.beam.sdk.transforms.PTransform
name, resourceHints
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description static <K,V>
KvSwap<K,V>create()
Returns aKvSwap<K, V>
PTransform
.PCollection<KV<V,K>>
expand(PCollection<KV<K,V>> in)
Override this method to specify how thisPTransform
should be expanded on the givenInputT
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Methods inherited from class org.apache.beam.sdk.transforms.PTransform
compose, compose, getAdditionalInputs, getDefaultOutputCoder, getDefaultOutputCoder, getDefaultOutputCoder, getKindString, getName, getResourceHints, populateDisplayData, setResourceHints, toString, validate, validate
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Method Detail
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create
public static <K,V> KvSwap<K,V> create()
Returns aKvSwap<K, V>
PTransform
.- Type Parameters:
K
- the type of the keys in the inputPCollection
and the values in the outputPCollection
V
- the type of the values in the inputPCollection
and the keys in the outputPCollection
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expand
public PCollection<KV<V,K>> expand(PCollection<KV<K,V>> in)
Description copied from class:PTransform
Override this method to specify how thisPTransform
should be expanded on the givenInputT
.NOTE: This method should not be called directly. Instead apply the
PTransform
should be applied to theInputT
using theapply
method.Composite transforms, which are defined in terms of other transforms, should return the output of one of the composed transforms. Non-composite transforms, which do not apply any transforms internally, should return a new unbound output and register evaluators (via backend-specific registration methods).
- Specified by:
expand
in classPTransform<PCollection<KV<K,V>>,PCollection<KV<V,K>>>
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