co.cask.cdap.format.io

Class StructuredRecordDatumWriter

java.lang.Object

co.cask.cdap.format.io.StructuredRecordDatumWriter

All Implemented Interfaces:

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

Direct Known Subclasses:

JsonStructuredRecordDatumWriter

public class StructuredRecordDatumWriter
extends Object
implements DatumWriter<co.cask.cdap.api.data.format.StructuredRecord>

A DatumWriter for writing out StructuredRecord to Encoder.

Constructor Summary

Constructors

Constructor and Description
StructuredRecordDatumWriter()

Method Summary

Modifier and Type	Method and Description
protected void	encode(Encoder encoder, co.cask.cdap.api.data.schema.Schema schema, Object value) Encodes a value based on a Schema
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	encodeArrayElement(Encoder encoder, co.cask.cdap.api.data.schema.Schema elementSchema, Object element) Encodes an element 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 java.lang.Object

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

Constructor Detail

StructuredRecordDatumWriter

public StructuredRecordDatumWriter()

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>

Throws:

IOException

encode

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

Encodes a value based on a Schema

Parameters:

encoder - the encoder to use

schema - the Schema of the value

value - the value to encode

Throws:

IOException - If failed to encode

encodeEnum

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

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.

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

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

Parameters:

encoder - The encoder to use

elementSchema - The Schema of the array element

size - Number of array elements

Throws:

IOException - If failed to encode

encodeArrayElement

protected void encodeArrayElement(Encoder encoder,
                                  co.cask.cdap.api.data.schema.Schema elementSchema,
                                  Object element)
                           throws IOException

Encodes an element of an array. This method will encode the element by calling the encode(Encoder, Schema, Object) method with the element schema.

Parameters:

encoder - The encoder to use

elementSchema - The Schema of the array element

element - the value to encode

Throws:

IOException - If failed to encode

encodeArrayEnd

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

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

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

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.

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

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 encode(Encoder, Schema, Object) method. Sub-class can override this to have different behavior.

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

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.

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

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

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

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

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

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

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

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.

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