PCollectionTuple (Apache Beam SDK 0.2.0-incubating API)

java.lang.Object
- org.apache.beam.sdk.values.PCollectionTuple

All Implemented Interfaces:: PInput, POutput

public class PCollectionTuple
extends Object
implements PInput, POutput

A PCollectionTuple is an immutable tuple of heterogeneously-typed PCollections, "keyed" by TupleTags. A PCollectionTuple can be used as the input or output of a PTransform taking or producing multiple PCollection inputs or outputs that can be of different types, for instance a ParDo with side outputs.

A PCollectionTuple can be created and accessed like follows:

 
 PCollection<String> pc1 = ...;
 PCollection<Integer> pc2 = ...;
 PCollection<Iterable<String>> pc3 = ...;

 // Create TupleTags for each of the PCollections to put in the
 // PCollectionTuple (the type of the TupleTag enables tracking the
 // static type of each of the PCollections in the PCollectionTuple):
 TupleTag<String> tag1 = new TupleTag<>();
 TupleTag<Integer> tag2 = new TupleTag<>();
 TupleTag<Iterable<String>> tag3 = new TupleTag<>();

 // Create a PCollectionTuple with three PCollections:
 PCollectionTuple pcs =
     PCollectionTuple.of(tag1, pc1)
                     .and(tag2, pc2)
                     .and(tag3, pc3);

 // Create an empty PCollectionTuple:
 Pipeline p = ...;
 PCollectionTuple pcs2 = PCollectionTuple.empty(p);

 // Get PCollections out of a PCollectionTuple, using the same tags
 // that were used to put them in:
 PCollection<Integer> pcX = pcs.get(tag2);
 PCollection<String> pcY = pcs.get(tag1);
 PCollection<Iterable<String>> pcZ = pcs.get(tag3);

 // Get a map of all PCollections in a PCollectionTuple:
 Map<TupleTag<?>, PCollection<?>> allPcs = pcs.getAll();

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`<T> PCollectionTuple`	`and(TupleTag<T> tag, PCollection<T> pc)` Returns a new `PCollectionTuple` that has each `PCollection` and `TupleTag` of this `PCollectionTuple` plus the given `PCollection` associated with the given `TupleTag`.
`<OutputT extends POutput> OutputT`	`apply(PTransform<PCollectionTuple,OutputT> t)` Like `apply(String, PTransform)` but defaulting to the name of the `PTransform`.
`<OutputT extends POutput> OutputT`	`apply(String name, PTransform<PCollectionTuple,OutputT> t)` Applies the given `PTransform` to this input `PCollectionTuple`, using `name` to identify this specific application of the transform.
`static PCollectionTuple`	`empty(Pipeline pipeline)` Returns an empty `PCollectionTuple` that is part of the given `Pipeline`.
`Collection<? extends PValue>`	`expand()` Expands this `PInput` into a list of its component output `PValues`.
`void`	`finishSpecifying()` After building, finalizes this `PInput` to make it ready for being used as an input to a `PTransform`.
`void`	`finishSpecifyingOutput()` As part of applying the producing `PTransform`, finalizes this output to make it ready for being used as an input and for running.
`<T> PCollection<T>`	`get(TupleTag<T> tag)` Returns the `PCollection` associated with the given `TupleTag` in this `PCollectionTuple`.
`Map<TupleTag<?>,PCollection<?>>`	`getAll()` Returns an immutable Map from `TupleTag` to corresponding `PCollection`, for all the members of this `PCollectionTuple`.
`Pipeline`	`getPipeline()` Returns the owning `Pipeline` of this `PInput`.
`<T> boolean`	`has(TupleTag<T> tag)` Returns whether this `PCollectionTuple` contains a `PCollection` with the given tag.
`static <T> PCollectionTuple`	`of(TupleTag<T> tag, PCollection<T> pc)` Returns a singleton `PCollectionTuple` containing the given `PCollection` keyed by the given `TupleTag`.
`static PCollectionTuple`	`ofPrimitiveOutputsInternal(Pipeline pipeline, TupleTagList outputTags, org.apache.beam.sdk.util.WindowingStrategy<?,?> windowingStrategy, PCollection.IsBounded isBounded)` Returns a `PCollectionTuple` with each of the given tags mapping to a new output `PCollection`.
`void`	`recordAsOutput(AppliedPTransform<?,?,?> transform)` Records that this `POutput` is an output of the given `PTransform`.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - empty
```
public static PCollectionTuple empty(Pipeline pipeline)
```
    Returns an empty PCollectionTuple that is part of the given Pipeline.
    A PCollectionTuple containing additional elements can be created by calling and(org.apache.beam.sdk.values.TupleTag<T>, org.apache.beam.sdk.values.PCollection<T>) on the result.
  - of
```
public static <T> PCollectionTuple of(TupleTag<T> tag,
                                      PCollection<T> pc)
```
    Returns a singleton PCollectionTuple containing the given PCollection keyed by the given TupleTag.
    A PCollectionTuple containing additional elements can be created by calling and(org.apache.beam.sdk.values.TupleTag<T>, org.apache.beam.sdk.values.PCollection<T>) on the result.
  - and
```
public <T> PCollectionTuple and(TupleTag<T> tag,
                                PCollection<T> pc)
```
    Returns a new PCollectionTuple that has each PCollection and TupleTag of this PCollectionTuple plus the given PCollection associated with the given TupleTag.
    The given TupleTag should not already be mapped to a PCollection in this PCollectionTuple.
    Each PCollection in the resulting PCollectionTuple must be part of the same Pipeline.
  - has
```
public <T> boolean has(TupleTag<T> tag)
```
    Returns whether this PCollectionTuple contains a PCollection with the given tag.
  - get
```
public <T> PCollection<T> get(TupleTag<T> tag)
```
    Returns the PCollection associated with the given TupleTag in this PCollectionTuple. Throws IllegalArgumentException if there is no such PCollection, i.e., !has(tag).
  - getAll
```
public Map<TupleTag<?>,PCollection<?>> getAll()
```
    Returns an immutable Map from TupleTag to corresponding PCollection, for all the members of this PCollectionTuple.
  - apply
```
public <OutputT extends POutput> OutputT apply(PTransform<PCollectionTuple,OutputT> t)
```
    Like apply(String, PTransform) but defaulting to the name of the PTransform.
    
    Returns:
    
    the output of the applied PTransform
  - apply
```
public <OutputT extends POutput> OutputT apply(String name,
                                               PTransform<PCollectionTuple,OutputT> t)
```
    Applies the given PTransform to this input PCollectionTuple, using name to identify this specific application of the transform. This name is used in various places, including the monitoring UI, logging, and to stably identify this application node in the job graph.
    
    Returns:
    
    the output of the applied PTransform
  - ofPrimitiveOutputsInternal
```
public static PCollectionTuple ofPrimitiveOutputsInternal(Pipeline pipeline,
                                                          TupleTagList outputTags,
                                                          org.apache.beam.sdk.util.WindowingStrategy<?,?> windowingStrategy,
                                                          PCollection.IsBounded isBounded)
```
    Returns a PCollectionTuple with each of the given tags mapping to a new output PCollection.
    For use by primitive transformations only.
  - getPipeline
```
public Pipeline getPipeline()
```
    Description copied from interface: PInput
    
    Returns the owning Pipeline of this PInput.
    
    Specified by:
    
    getPipeline in interface PInput
    
    Specified by:
    
    getPipeline in interface POutput
  - expand
```
public Collection<? extends PValue> expand()
```
    Description copied from interface: PInput
    Expands this PInput into a list of its component output PValues.
    - A PValue expands to itself.
    - A tuple or list of PValues (such as PCollectionTuple or PCollectionList) expands to its component PValue PValues.
    Not intended to be invoked directly by user code.
    Specified by:
    
    expand in interface PInput
    
    Specified by:
    
    expand in interface POutput
  - recordAsOutput
```
public void recordAsOutput(AppliedPTransform<?,?,?> transform)
```
    Description copied from interface: POutput
    
    Records that this POutput is an output of the given PTransform.
    For a compound POutput, it is advised to call this method on each component POutput.
    This is not intended to be invoked by user code, but is automatically invoked as part of applying the producing PTransform.
    
    Specified by:
    
    recordAsOutput in interface POutput
  - finishSpecifying
```
public void finishSpecifying()
```
    Description copied from interface: PInput
    
    After building, finalizes this PInput to make it ready for being used as an input to a PTransform.
    Automatically invoked whenever apply() is invoked on this PInput, so users do not normally call this explicitly.
    
    Specified by:
    
    finishSpecifying in interface PInput
  - finishSpecifyingOutput
```
public void finishSpecifyingOutput()
```
    Description copied from interface: POutput
    
    As part of applying the producing PTransform, finalizes this output to make it ready for being used as an input and for running.
    This includes ensuring that all PCollections have Coders specified or defaulted.
    Automatically invoked whenever this POutput is used as a PInput to another PTransform, or if never used as a PInput, when Pipeline.run() is called, so users do not normally call this explicitly.
    
    Specified by:
    
    finishSpecifyingOutput in interface POutput

Class PCollectionTuple

Method Summary

Methods inherited from class java.lang.Object

Method Detail

empty

of

and

has

get

getAll

apply

apply

ofPrimitiveOutputsInternal

getPipeline

expand

recordAsOutput

finishSpecifying

finishSpecifyingOutput