org.apache.beam.sdk.extensions.jackson

Class AsJsons<InputT>

java.lang.Object

org.apache.beam.sdk.transforms.PTransform<PCollection<InputT>,PCollection<java.lang.String>>

org.apache.beam.sdk.extensions.jackson.AsJsons<InputT>

All Implemented Interfaces:

java.io.Serializable, HasDisplayData

public class AsJsons<InputT>
extends PTransform<PCollection<InputT>,PCollection<java.lang.String>>

PTransform for serializing objects to JSON Strings. Transforms a PCollection<InputT> into a PCollection of JSON Strings representing objects in the original PCollection using Jackson.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	AsJsons.AsJsonsWithFailures<FailureT> A PTransform that adds exception handling to AsJsons.

Field Summary

Fields inherited from class org.apache.beam.sdk.transforms.PTransform

name, resourceHints

Method Summary

Modifier and Type	Method and Description
<NewFailureT> AsJsons.AsJsonsWithFailures<NewFailureT>	exceptionsInto(TypeDescriptor<NewFailureT> failureTypeDescriptor) Returns a new AsJsons.AsJsonsWithFailures transform that catches exceptions raised while writing JSON elements, with the given type descriptor used for the failure collection but the exception handler yet to be specified using AsJsons.AsJsonsWithFailures.exceptionsVia(ProcessFunction).
AsJsons.AsJsonsWithFailures<KV<InputT,java.util.Map<java.lang.String,java.lang.String>>>	exceptionsVia() Returns a new AsJsons.AsJsonsWithFailures transform that catches exceptions raised while writing JSON elements, passing the raised exception instance and the input element being processed through the default exception handler DefaultExceptionAsMapHandler and emitting the result to a failure collection.
<FailureT> AsJsons.AsJsonsWithFailures<FailureT>	exceptionsVia(InferableFunction<WithFailures.ExceptionElement<InputT>,FailureT> exceptionHandler) Returns a new AsJsons.AsJsonsWithFailures transform that catches exceptions raised while writing JSON elements, passing the raised exception instance and the input element being processed through the given exceptionHandler and emitting the result to a failure collection.
PCollection<java.lang.String>	expand(PCollection<InputT> input) Override this method to specify how this PTransform should be expanded on the given InputT.
static <InputT> AsJsons<InputT>	of(java.lang.Class<? extends InputT> inputClass) Creates a AsJsons PTransform that will transform a PCollection<InputT> into a PCollection of JSON Strings representing those objects using a Jackson ObjectMapper.
AsJsons<InputT>	withMapper(ObjectMapper mapper) Use custom Jackson ObjectMapper instead of the default one.

Methods inherited from class org.apache.beam.sdk.transforms.PTransform

compose, compose, getAdditionalInputs, getDefaultOutputCoder, getDefaultOutputCoder, getDefaultOutputCoder, getKindString, getName, getResourceHints, populateDisplayData, setResourceHints, toString, validate

Methods inherited from class java.lang.Object

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

Method Detail

of

public static <InputT> AsJsons<InputT> of(java.lang.Class<? extends InputT> inputClass)

Creates a AsJsons PTransform that will transform a PCollection<InputT> into a PCollection of JSON Strings representing those objects using a Jackson ObjectMapper.

withMapper

public AsJsons<InputT> withMapper(ObjectMapper mapper)

Use custom Jackson ObjectMapper instead of the default one.

exceptionsInto

@Experimental(value=WITH_EXCEPTIONS)
public <NewFailureT> AsJsons.AsJsonsWithFailures<NewFailureT> exceptionsInto(TypeDescriptor<NewFailureT> failureTypeDescriptor)

Returns a new AsJsons.AsJsonsWithFailures transform that catches exceptions raised while writing JSON elements, with the given type descriptor used for the failure collection but the exception handler yet to be specified using AsJsons.AsJsonsWithFailures.exceptionsVia(ProcessFunction).

See WithFailures documentation for usage patterns of the returned WithFailures.Result.

exceptionsVia

@Experimental(value=WITH_EXCEPTIONS)
public <FailureT> AsJsons.AsJsonsWithFailures<FailureT> exceptionsVia(InferableFunction<WithFailures.ExceptionElement<InputT>,FailureT> exceptionHandler)

Returns a new AsJsons.AsJsonsWithFailures transform that catches exceptions raised while writing JSON elements, passing the raised exception instance and the input element being processed through the given exceptionHandler and emitting the result to a failure collection.

See WithFailures documentation for usage patterns of the returned WithFailures.Result.

Example usage:

 WithFailures.Result<PCollection<String>, KV<MyPojo, Map<String, String>>> result =
     pojos.apply(
         AsJsons.of(MyPojo.class)
             .exceptionsVia(new WithFailures.ExceptionAsMapHandler<MyPojo>() {}));

 PCollection<String> output = result.output(); // valid json elements
 PCollection<KV<MyPojo, Map<String, String>>> failures = result.failures();
 

exceptionsVia

@Experimental(value=WITH_EXCEPTIONS)
public AsJsons.AsJsonsWithFailures<KV<InputT,java.util.Map<java.lang.String,java.lang.String>>> exceptionsVia()

Returns a new AsJsons.AsJsonsWithFailures transform that catches exceptions raised while writing JSON elements, passing the raised exception instance and the input element being processed through the default exception handler DefaultExceptionAsMapHandler and emitting the result to a failure collection.

See DefaultExceptionAsMapHandler for more details about default handler behavior.

See WithFailures documentation for usage patterns of the returned WithFailures.Result.

Example usage:

 WithFailures.Result<PCollection<String>, KV<MyPojo, Map<String, String>>> result =
     pojos.apply(
         AsJsons.of(MyPojo.class)
             .exceptionsVia());

 PCollection<String> output = result.output(); // valid json elements
 PCollection<KV<MyPojo, Map<String, String>>> failures = result.failures();
 

expand

public PCollection<java.lang.String> expand(PCollection<InputT> input)

Description copied from class: PTransform

Override this method to specify how this PTransform should be expanded on the given InputT.

NOTE: This method should not be called directly. Instead apply the PTransform should be applied to the InputT using the apply 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 class PTransform<PCollection<InputT>,PCollection<java.lang.String>>