co.cask.cdap.format.io

Class JsonStructuredRecordDatumWriter

java.lang.Object

co.cask.cdap.format.io.StructuredRecordDatumWriter

co.cask.cdap.format.io.JsonStructuredRecordDatumWriter

All Implemented Interfaces:

DatumWriter<co.cask.cdap.api.data.format.StructuredRecord>

public final class JsonStructuredRecordDatumWriter
extends StructuredRecordDatumWriter

A StructuredRecordDatumWriter for encoding StructuredRecord to json.

Constructor Summary

Constructors

Constructor and Description
JsonStructuredRecordDatumWriter()

Method Summary

Modifier and Type	Method and Description
void	encode(co.cask.cdap.api.data.format.StructuredRecord data, Encoder encoder)
protected void	encodeArrayBegin(Encoder encoder, co.cask.cdap.api.data.schema.Schema elementSchema, int size) Encodes the beginning of an array.
protected void	encodeArrayEnd(Encoder encoder, co.cask.cdap.api.data.schema.Schema elementSchema, int size) Encodes the ending of an array.
protected void	encodeEnum(Encoder encoder, co.cask.cdap.api.data.schema.Schema enumSchema, Object value) Encodes a enum value.
protected void	encodeMapBegin(Encoder encoder, co.cask.cdap.api.data.schema.Schema keySchema, co.cask.cdap.api.data.schema.Schema valueSchema, int size) Encodes the beginning of a Map.
protected void	encodeMapEnd(Encoder encoder, co.cask.cdap.api.data.schema.Schema keySchema, co.cask.cdap.api.data.schema.Schema valueSchema, int size) Encodes the ending of a Map.
protected void	encodeMapEntry(Encoder encoder, co.cask.cdap.api.data.schema.Schema keySchema, co.cask.cdap.api.data.schema.Schema valueSchema, Map.Entry<?,?> entry) Encodes a map entry.
protected void	encodeRecordBegin(Encoder encoder, co.cask.cdap.api.data.schema.Schema schema) Encodes the beginning of record.
protected void	encodeRecordEnd(Encoder encoder, co.cask.cdap.api.data.schema.Schema schema) Encodes the ending of record.
protected void	encodeRecordField(Encoder encoder, co.cask.cdap.api.data.schema.Schema.Field field, Object value) Encodes a record field.
protected void	encodeUnion(Encoder encoder, co.cask.cdap.api.data.schema.Schema schema, int matchingIdx, Object value) Encodes a union value.

Methods inherited from class co.cask.cdap.format.io.StructuredRecordDatumWriter

encode, encodeArrayElement

Methods inherited from class java.lang.Object

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

Constructor Detail

JsonStructuredRecordDatumWriter

public JsonStructuredRecordDatumWriter()

Method Detail

encode

public void encode(co.cask.cdap.api.data.format.StructuredRecord data,
                   Encoder encoder)
            throws IOException

Specified by:

encode in interface DatumWriter<co.cask.cdap.api.data.format.StructuredRecord>

Overrides:

encode in class StructuredRecordDatumWriter

Throws:

IOException

encodeEnum

protected void encodeEnum(Encoder encoder,
                          co.cask.cdap.api.data.schema.Schema enumSchema,
                          Object value)
                   throws IOException

Description copied from class: StructuredRecordDatumWriter

Encodes a enum value. This method will encode with the enum index of the enum value according to the Schema. Sub-class can override this to have different behavior.

Overrides:

encodeEnum in class StructuredRecordDatumWriter

Parameters:

encoder - The encoder to use

enumSchema - The Schema for the enum field

value - The enum value

Throws:

IOException - If failed to encode

encodeArrayBegin

protected void encodeArrayBegin(Encoder encoder,
                                co.cask.cdap.api.data.schema.Schema elementSchema,
                                int size)
                         throws IOException

Description copied from class: StructuredRecordDatumWriter

Encodes the beginning of an array. This method will encode with the size of the array. Sub-class can override this to have different behavior

Overrides:

encodeArrayBegin in class StructuredRecordDatumWriter

Parameters:

encoder - The encoder to use

elementSchema - The Schema of the array element

size - Number of array elements

Throws:

IOException - If failed to encode

encodeArrayEnd

protected void encodeArrayEnd(Encoder encoder,
                              co.cask.cdap.api.data.schema.Schema elementSchema,
                              int size)
                       throws IOException

Description copied from class: StructuredRecordDatumWriter

Encodes the ending of an array. This method writes out 0 to signal the end of the array. Sub-class can override this to have different behavior

Overrides:

encodeArrayEnd in class StructuredRecordDatumWriter

Parameters:

encoder - The encoder to use

elementSchema - The Schema of the array element

size - Number of array elements

Throws:

IOException - If failed to encode

encodeMapBegin

protected void encodeMapBegin(Encoder encoder,
                              co.cask.cdap.api.data.schema.Schema keySchema,
                              co.cask.cdap.api.data.schema.Schema valueSchema,
                              int size)
                       throws IOException

Description copied from class: StructuredRecordDatumWriter

Encodes the beginning of a Map. This method will write out the size of the map. Sub-class can override this to have different behavior.

Overrides:

encodeMapBegin in class StructuredRecordDatumWriter

Parameters:

encoder - The encoder to use

keySchema - The Schema of the map key

valueSchema - The Schema of the map value

size - size of the map

Throws:

IOException - If failed to encode

encodeMapEntry

protected void encodeMapEntry(Encoder encoder,
                              co.cask.cdap.api.data.schema.Schema keySchema,
                              co.cask.cdap.api.data.schema.Schema valueSchema,
                              Map.Entry<?,?> entry)
                       throws IOException

Description copied from class: StructuredRecordDatumWriter

Encodes a map entry. This method will write out the key based on the key schema, followed by the value based on the value schema by calling the StructuredRecordDatumWriter.encode(Encoder, Schema, Object) method. Sub-class can override this to have different behavior.

Overrides:

encodeMapEntry in class StructuredRecordDatumWriter

Parameters:

encoder - The encoder to use

keySchema - The Schema of the map key

valueSchema - The Schema of the map value

entry - the map entry to encode

Throws:

IOException - If failed to encode

encodeMapEnd

protected void encodeMapEnd(Encoder encoder,
                            co.cask.cdap.api.data.schema.Schema keySchema,
                            co.cask.cdap.api.data.schema.Schema valueSchema,
                            int size)
                     throws IOException

Description copied from class: StructuredRecordDatumWriter

Encodes the ending of a Map. This method writes out 0 to signal the end of the map. Sub-class can override this to have different behavior.

Overrides:

encodeMapEnd in class StructuredRecordDatumWriter

Parameters:

encoder - The encoder to use

keySchema - The Schema of the map key

valueSchema - The Schema of the map value

size - size of the map

Throws:

IOException - If failed to encode

encodeRecordBegin

protected void encodeRecordBegin(Encoder encoder,
                                 co.cask.cdap.api.data.schema.Schema schema)
                          throws IOException

Description copied from class: StructuredRecordDatumWriter

Encodes the beginning of record. This method is an no-op. Sub-class can override this to have different behavior.

Overrides:

encodeRecordBegin in class StructuredRecordDatumWriter

Parameters:

encoder - The encoder to use

schema - The Schema of the record

Throws:

IOException - If failed to encode

encodeRecordField

protected void encodeRecordField(Encoder encoder,
                                 co.cask.cdap.api.data.schema.Schema.Field field,
                                 Object value)
                          throws IOException

Description copied from class: StructuredRecordDatumWriter

Encodes a record field. This method will encode the field based on the field schema by calling the StructuredRecordDatumWriter.encode(Encoder, Schema, Object) method. Sub-class can override this to have different behavior.

Overrides:

encodeRecordField in class StructuredRecordDatumWriter

Parameters:

encoder - The encoder to use

field - The Schema.Field to encode

value - the field value to encode

Throws:

IOException - If failed to encode

encodeRecordEnd

protected void encodeRecordEnd(Encoder encoder,
                               co.cask.cdap.api.data.schema.Schema schema)
                        throws IOException

Description copied from class: StructuredRecordDatumWriter

Encodes the ending of record. This method is an no-op. Sub-class can override this to have different behavior.

Overrides:

encodeRecordEnd in class StructuredRecordDatumWriter

Parameters:

encoder - The encoder to use

schema - The Schema of the record

Throws:

IOException - If failed to encode

encodeUnion

protected void encodeUnion(Encoder encoder,
                           co.cask.cdap.api.data.schema.Schema schema,
                           int matchingIdx,
                           Object value)
                    throws IOException

Description copied from class: StructuredRecordDatumWriter

Encodes a union value. This method will write out the index of the matching schema in the union schema, followed by encoding the value. Sub-class can override this to have different behavior.

Overrides:

encodeUnion in class StructuredRecordDatumWriter

Parameters:

encoder - The encoder to use

schema - The union schema

matchingIdx - The index in the union schema that matches the data type

value - The value to encode

Throws:

IOException - If failed to encode