org.apache.avro.mapreduce

Class AvroKeyValueRecordWriter<K,V>

java.lang.Object

org.apache.hadoop.mapreduce.RecordWriter<K,V>

org.apache.avro.mapreduce.AvroKeyValueRecordWriter<K,V>

Type Parameters:

K - The type of key to write.

V - The type of value to write.

All Implemented Interfaces:

Syncable

public class AvroKeyValueRecordWriter<K,V>
extends RecordWriter<K,V>
implements Syncable

Writes key/value pairs to an Avro container file.

Each entry in the Avro container file will be a generic record with two fields, named 'key' and 'value'. The input types may be basic Writable objects like Text or IntWritable, or they may be AvroWrapper subclasses (AvroKey or AvroValue). Writable objects will be converted to their corresponding Avro types when written to the generic record key/value pair.

Constructor Summary

Constructors

Constructor and Description
AvroKeyValueRecordWriter(AvroDatumConverter<K,?> keyConverter, AvroDatumConverter<V,?> valueConverter, GenericData dataModel, CodecFactory compressionCodec, OutputStream outputStream) Constructor.
AvroKeyValueRecordWriter(AvroDatumConverter<K,?> keyConverter, AvroDatumConverter<V,?> valueConverter, GenericData dataModel, CodecFactory compressionCodec, OutputStream outputStream, int syncInterval) Constructor.

Method Summary

Modifier and Type	Method and Description
void	close(TaskAttemptContext context)
Schema	getWriterSchema() Gets the writer schema for the key/value pair generic record.
long	sync() Return the current position as a value that may be passed to DataFileReader.seek(long).
void	write(K key, V value)

Methods inherited from class java.lang.Object

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

Constructor Detail

AvroKeyValueRecordWriter

public AvroKeyValueRecordWriter(AvroDatumConverter<K,?> keyConverter,
                                AvroDatumConverter<V,?> valueConverter,
                                GenericData dataModel,
                                CodecFactory compressionCodec,
                                OutputStream outputStream,
                                int syncInterval)
                         throws IOException

Constructor.

Parameters:

keyConverter - A key to Avro datum converter.

valueConverter - A value to Avro datum converter.

dataModel - The data model for key and value.

compressionCodec - A compression codec factory for the Avro container file.

outputStream - The output stream to write the Avro container file to.

syncInterval - The sync interval for the Avro container file.

Throws:

IOException - If the record writer cannot be opened.

AvroKeyValueRecordWriter

public AvroKeyValueRecordWriter(AvroDatumConverter<K,?> keyConverter,
                                AvroDatumConverter<V,?> valueConverter,
                                GenericData dataModel,
                                CodecFactory compressionCodec,
                                OutputStream outputStream)
                         throws IOException

Constructor.

Parameters:

keyConverter - A key to Avro datum converter.

valueConverter - A value to Avro datum converter.

dataModel - The data model for key and value.

compressionCodec - A compression codec factory for the Avro container file.

outputStream - The output stream to write the Avro container file to.

Throws:

IOException - If the record writer cannot be opened.

Method Detail

getWriterSchema

public Schema getWriterSchema()

Gets the writer schema for the key/value pair generic record.

Returns:

The writer schema used for entries of the Avro container file.

write

public void write(K key,
                  V value)
           throws IOException

Specified by:

write in class RecordWriter<K,V>

Throws:

IOException

close

public void close(TaskAttemptContext context)
           throws IOException

Specified by:

close in class RecordWriter<K,V>

Throws:

IOException

sync

public long sync()
          throws IOException

Return the current position as a value that may be passed to DataFileReader.seek(long). Forces the end of the current block, emitting a synchronization marker.

Specified by:

sync in interface Syncable

Throws:

IOException - - if an error occurred while attempting to sync.