org.apache.flink.formats.json.canal

Class CanalJsonDeserializationSchema

java.lang.Object

org.apache.flink.formats.json.canal.CanalJsonDeserializationSchema

All Implemented Interfaces:

Serializable, DeserializationSchema<RowData>, ResultTypeQueryable<RowData>

public final class CanalJsonDeserializationSchema
extends Object
implements DeserializationSchema<RowData>

Deserialization schema from Canal JSON to Flink Table/SQL internal data structure RowData. The deserialization schema knows Canal's schema definition and can extract the database data and convert into RowData with RowKind.

Deserializes a byte[] message as a JSON object and reads the specified fields.

Failures during deserialization are forwarded as wrapped IOExceptions.

See Also:

Alibaba Canal, Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CanalJsonDeserializationSchema.Builder A builder for creating a CanalJsonDeserializationSchema.

Nested classes/interfaces inherited from interface org.apache.flink.api.common.serialization.DeserializationSchema

DeserializationSchema.InitializationContext

Method Summary

Modifier and Type	Method and Description
static CanalJsonDeserializationSchema.Builder	builder(DataType physicalDataType, List<org.apache.flink.formats.json.canal.CanalJsonDecodingFormat.ReadableMetadata> requestedMetadata, TypeInformation<RowData> producedTypeInfo) Creates A builder for building a CanalJsonDeserializationSchema.
RowData	deserialize(byte[] message) Deserializes the byte message.
void	deserialize(byte[] message, Collector<RowData> out) Deserializes the byte message.
boolean	equals(Object o)
TypeInformation<RowData>	getProducedType() Gets the data type (as a TypeInformation) produced by this function or input format.
int	hashCode()
boolean	isEndOfStream(RowData nextElement) Method to decide whether the element signals the end of the stream.
void	open(DeserializationSchema.InitializationContext context) Initialization method for the schema.

Methods inherited from class java.lang.Object

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

Method Detail

builder

public static CanalJsonDeserializationSchema.Builder builder(DataType physicalDataType,
                                                             List<org.apache.flink.formats.json.canal.CanalJsonDecodingFormat.ReadableMetadata> requestedMetadata,
                                                             TypeInformation<RowData> producedTypeInfo)

Creates A builder for building a CanalJsonDeserializationSchema.

open

public void open(DeserializationSchema.InitializationContext context)
          throws Exception

Description copied from interface: DeserializationSchema

Initialization method for the schema. It is called before the actual working methods DeserializationSchema.deserialize(byte[]) and thus suitable for one time setup work.

The provided DeserializationSchema.InitializationContext can be used to access additional features such as e.g. registering user metrics.

Specified by:

open in interface DeserializationSchema<RowData>

Parameters:

context - Contextual information that can be used during initialization.

Throws:

Exception

deserialize

public RowData deserialize(byte[] message)
                    throws IOException

Description copied from interface: DeserializationSchema

Deserializes the byte message.

Specified by:

deserialize in interface DeserializationSchema<RowData>

Parameters:

message - The message, as a byte array.

Returns:

The deserialized message as an object (null if the message cannot be deserialized).

Throws:

IOException

deserialize

public void deserialize(@Nullable
                        byte[] message,
                        Collector<RowData> out)
                 throws IOException

Description copied from interface: DeserializationSchema

Deserializes the byte message.

Can output multiple records through the Collector. Note that number and size of the produced records should be relatively small. Depending on the source implementation records can be buffered in memory or collecting records might delay emitting checkpoint barrier.

Specified by:

deserialize in interface DeserializationSchema<RowData>

Parameters:

message - The message, as a byte array.

out - The collector to put the resulting messages.

Throws:

IOException

isEndOfStream

public boolean isEndOfStream(RowData nextElement)

Description copied from interface: DeserializationSchema

Method to decide whether the element signals the end of the stream. If true is returned the element won't be emitted.

Specified by:

isEndOfStream in interface DeserializationSchema<RowData>

Parameters:

nextElement - The element to test for the end-of-stream signal.

Returns:

True, if the element signals end of stream, false otherwise.

getProducedType

public TypeInformation<RowData> getProducedType()

Description copied from interface: ResultTypeQueryable

Gets the data type (as a TypeInformation) produced by this function or input format.

Specified by:

getProducedType in interface ResultTypeQueryable<RowData>

Returns:

The data type produced by this function or input format.

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object