Package org.apache.beam.sdk.coders

Class CoderRegistry

java.lang.Object

org.apache.beam.sdk.coders.CoderRegistry

public class CoderRegistry
extends Object

A CoderRegistry allows creating a Coder for a given Java class or type descriptor.

Creation of the Coder is delegated to one of the many registered coder providers based upon the registration order.

By default, the coder provider precedence order is as follows:

• Coder providers registered programmatically with registerCoderProvider(CoderProvider).
• A default coder provider for common Java (Byte, Double, List, ...) and Apache Beam (KV, ...) types.
• Coder providers registered automatically through a CoderProviderRegistrar using a ServiceLoader. Note that the ServiceLoader registration order is consistent but may change due to the addition or removal of libraries exposed to the application. This can impact the coder returned if multiple coder providers are capable of supplying a coder for the specified type.

Note that if multiple coder providers can provide a Coder for a given type, the precedence order above defines which CoderProvider is chosen.

Method Summary

Modifier and Type	Method	Description
static CoderRegistry	createDefault()	Creates a CoderRegistry containing registrations for all standard coders part of the core Java Apache Beam SDK and also any registrations provided by coder registrars.
<T, OutputT> Coder<OutputT>	getCoder(Class<? extends T> subClass, Class<T> baseClass, Map<Type,? extends Coder<?>> knownCoders, TypeVariable<?> param)	Deprecated. This method is to change in an unknown backwards incompatible way once support for this functionality is refined.
<T> Coder<T>	getCoder(Class<T> clazz)	Returns the Coder to use for values of the given class.
<InputT, OutputT> Coder<OutputT>	getCoder(TypeDescriptor<OutputT> typeDescriptor, TypeDescriptor<InputT> inputTypeDescriptor, Coder<InputT> inputCoder)	Deprecated. This method is to change in an unknown backwards incompatible way once support for this functionality is refined.
<T> Coder<T>	getCoder(TypeDescriptor<T> type)	Returns the Coder to use for values of the given type.
<InputT, OutputT> Coder<OutputT>	getOutputCoder(SerializableFunction<InputT,OutputT> fn, Coder<InputT> inputCoder)	Deprecated. This method is to change in an unknown backwards incompatible way once support for this functionality is refined.
void	registerCoderForClass(Class<?> clazz, Coder<?> coder)	Registers the provided Coder for the given class.
void	registerCoderForType(TypeDescriptor<?> type, Coder<?> coder)	Registers the provided Coder for the given type.
void	registerCoderProvider(CoderProvider coderProvider)	Registers coderProvider as a potential CoderProvider which can produce Coder instances.

Methods inherited from class java.lang.Object

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

Method Details

createDefault

public static CoderRegistry createDefault()

Creates a CoderRegistry containing registrations for all standard coders part of the core Java Apache Beam SDK and also any registrations provided by coder registrars.

Multiple registrations which can produce a coder for a given type result in a Coder created by the (in order of precedence):

• coder providers registered programmatically through registerCoderProvider(org.apache.beam.sdk.coders.CoderProvider).
• coder providers for core types found within the Apache Beam Java SDK being used.
• The coder providers from the CoderProviderRegistrar with the lexicographically smallest class name being used.

registerCoderProvider

public void registerCoderProvider(CoderProvider coderProvider)

Registers coderProvider as a potential CoderProvider which can produce Coder instances.

This method prioritizes this CoderProvider over all prior registered coders.

See CoderProviders for common CoderProvider patterns.

registerCoderForClass

public void registerCoderForClass(Class<?> clazz,
 Coder<?> coder)

Registers the provided Coder for the given class.

Note that this is equivalent to registerCoderForType(TypeDescriptor.of(clazz)). See registerCoderForType(TypeDescriptor, Coder) for further details.

registerCoderForType

public void registerCoderForType(TypeDescriptor<?> type,
 Coder<?> coder)

Registers the provided Coder for the given type.

Note that this is equivalent to registerCoderProvider(CoderProviders.forCoder(type, coder)). See registerCoderProvider(org.apache.beam.sdk.coders.CoderProvider) and CoderProviders.forCoder(org.apache.beam.sdk.values.TypeDescriptor<?>, org.apache.beam.sdk.coders.Coder<?>) for further details.

getCoder

public <T> Coder<T> getCoder(Class<T> clazz)
                      throws CannotProvideCoderException

Returns the Coder to use for values of the given class.

Throws:

CannotProvideCoderException - if a Coder cannot be provided

getCoder

public <T> Coder<T> getCoder(TypeDescriptor<T> type)
                      throws CannotProvideCoderException

Returns the Coder to use for values of the given type.

Throws:

CannotProvideCoderException - if a Coder cannot be provided

getCoder

@Deprecated
@Internal
public <InputT,
OutputT> Coder<OutputT> getCoder(TypeDescriptor<OutputT> typeDescriptor,
 TypeDescriptor<InputT> inputTypeDescriptor,
 Coder<InputT> inputCoder)
                                          throws CannotProvideCoderException

Deprecated.

This method is to change in an unknown backwards incompatible way once support for this functionality is refined.

Returns the Coder for values of the given type, where the given input type uses the given Coder.

Throws:

CannotProvideCoderException - if a Coder cannot be provided

getOutputCoder

@Deprecated
@Internal
public <InputT,
OutputT> Coder<OutputT> getOutputCoder(SerializableFunction<InputT,OutputT> fn,
 Coder<InputT> inputCoder)
                                                throws CannotProvideCoderException

Deprecated.

This method is to change in an unknown backwards incompatible way once support for this functionality is refined.

Returns the Coder to use on elements produced by this function, given the Coder used for its input elements.

Throws:

CannotProvideCoderException - if a Coder cannot be provided

getCoder

@Deprecated
@Internal
public <T,
OutputT> Coder<OutputT> getCoder(Class<? extends T> subClass,
 Class<T> baseClass,
 Map<Type,? extends Coder<?>> knownCoders,
 TypeVariable<?> param)
                                     throws CannotProvideCoderException

Deprecated.

This method is to change in an unknown backwards incompatible way once support for this functionality is refined.

Returns the Coder to use for the specified type parameter specialization of the subclass, given Coders to use for all other type parameters (if any).

Throws:

CannotProvideCoderException - if a Coder cannot be provided