org.apache.beam.sdk.values

Class PValueBase

java.lang.Object

org.apache.beam.sdk.values.PValueBase

All Implemented Interfaces:

PInput, POutput, PValue

Direct Known Subclasses:

PCollection, PCollectionViews.SimplePCollectionView

@Internal
public abstract class PValueBase
extends java.lang.Object
implements PValue

For internal use. No backwards compatibility guarantees.

An abstract base class that provides default implementations for some methods of PValue.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	PValueBase() No-arg constructor for Java serialization only.
protected	PValueBase(Pipeline pipeline)

Method Summary

Modifier and Type	Method and Description
java.util.Map<TupleTag<?>,PValue>	expand() Expands this POutput into a list of its component output PValues.
void	finishSpecifying(PInput input, PTransform<?,?> transform) After building, finalizes this PValue to make it ready for being used as an input to a PTransform.
void	finishSpecifyingOutput(java.lang.String transformName, PInput input, PTransform<?,?> transform) As part of applying the producing PTransform, finalizes this output to make it ready for being used as an input and for running.
protected java.lang.String	getKindString() Returns a String capturing the kind of this PValueBase.
java.lang.String	getName() Returns the name of this PValueBase.
Pipeline	getPipeline() Returns the owning Pipeline of this POutput.
PValueBase	setName(java.lang.String name) Sets the name of this PValueBase.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

PValueBase

protected PValueBase(Pipeline pipeline)

PValueBase

protected PValueBase()

No-arg constructor for Java serialization only. The resulting PValueBase is unlikely to be valid.

Method Detail

getName

public java.lang.String getName()

Returns the name of this PValueBase.

By default, the name of a PValueBase is based on the name of the PTransform that produces it. It can be specified explicitly by calling setName(java.lang.String).

Specified by:

getName in interface PValue

Throws:

java.lang.IllegalStateException - if the name hasn't been set yet

setName

public PValueBase setName(java.lang.String name)

Sets the name of this PValueBase. Returns this.

Throws:

java.lang.IllegalStateException - if this PValueBase has already been finalized and may no longer be set.

expand

public final java.util.Map<TupleTag<?>,PValue> expand()

Description copied from interface: PValue

Expands this POutput 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..

A PValue always expands into itself. Calling PValue.expand() on a PValue is almost never appropriate.

Specified by:

expand in interface PInput

Specified by:

expand in interface POutput

Specified by:

expand in interface PValue

finishSpecifying

public void finishSpecifying(PInput input,
                             PTransform<?,?> transform)

Description copied from interface: PValue

After building, finalizes this PValue to make it ready for being used as an input to a PTransform.

Automatically invoked whenever apply() is invoked on this PValue. Users should not normally call this explicitly.

Specified by:

finishSpecifying in interface PValue

Parameters:

input - the PInput the PTransform was applied to to produce this output

transform - the PTransform that produced this PValue

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getKindString

protected java.lang.String getKindString()

Returns a String capturing the kind of this PValueBase.

By default, uses the base name of the current class as its kind string.

getPipeline

public Pipeline getPipeline()

Description copied from interface: POutput

Returns the owning Pipeline of this POutput.

Specified by:

getPipeline in interface PInput

Specified by:

getPipeline in interface POutput

finishSpecifyingOutput

public void finishSpecifyingOutput(java.lang.String transformName,
                                   PInput input,
                                   PTransform<?,?> transform)

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 output, after POutput.finishSpecifyingOutput(String, PInput, PTransform) has been called on each component PValue returned by POutput.expand().

Specified by:

finishSpecifyingOutput in interface POutput