/*
* Copyright (c) 2010-2012 LinkedIn, Inc
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package krati.store.avro;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import krati.io.SerializationException;
import krati.io.Serializer;
import org.apache.avro.Schema;
import org.apache.avro.generic.GenericData;
import org.apache.avro.generic.GenericDatumReader;
import org.apache.avro.generic.GenericDatumWriter;
import org.apache.avro.generic.GenericRecord;
import org.apache.avro.generic.GenericData.Record;
import org.apache.avro.io.BinaryEncoder;
import org.apache.avro.io.Decoder;
import org.apache.avro.io.DecoderFactory;
import org.apache.avro.io.Encoder;
import org.apache.avro.io.ResolvingDecoder;
/**
* AvroGenericRecordResolvingSerializer requires a writer schema and a reader schema.
* The writer schema is used by {@link #serialize(GenericRecord)} and the reader
* schema is used by {@link #deserialize(byte[])}.
*
* @author jwu
* @since 02/01, 2012
*/
public class AvroGenericRecordResolvingSerializer implements Serializer<GenericRecord> {
private final Schema _writer;
private final Schema _reader;
private final Object _resolver;
/**
* Creates a new instance of AvroGenericRecordResolvingSerializer with the specified
* writer and reader.
*
* @param writer - the writer {@link Schema} used by {@link #serialize(GenericRecord)}.
* @param reader - the reader {@link Schema} used by {@link #deserialize(byte[])}.
* @throws IOException if the {@link ResolvingDecoder} failed to resolve the reader versus the writer.
*/
public AvroGenericRecordResolvingSerializer(Schema writer, Schema reader) throws IOException {
this._writer = writer;
this._reader = reader;
this._resolver = ResolvingDecoder.resolve(writer, reader);
}
@Override
public GenericRecord deserialize(byte[] bytes) throws SerializationException {
if (bytes == null) {
return null;
}
try {
ByteArrayInputStream in = new ByteArrayInputStream(bytes);
Decoder decoder = DecoderFactory.defaultFactory().createBinaryDecoder(in, null);
ResolvingDecoder resolvingDecoder = new ResolvingDecoder(_resolver, decoder);
GenericDatumReader<Record> datumReader = new GenericDatumReader<Record>(_reader);
GenericData.Record record = new GenericData.Record(_reader);
datumReader.read(record, resolvingDecoder);
return record;
} catch(Exception e) {
throw new SerializationException("Failed to deserialize", e);
}
}
@Override
public byte[] serialize(GenericRecord record) throws SerializationException {
if(record == null) {
return null;
}
try {
ByteArrayOutputStream out = new ByteArrayOutputStream();
Encoder encoder = new BinaryEncoder(out);
GenericDatumWriter<GenericRecord> datumWriter = new GenericDatumWriter<GenericRecord>(_writer);
datumWriter.write(record, encoder);
encoder.flush();
return out.toByteArray();
} catch(Exception e) {
throw new SerializationException("Failed to serialize", e);
}
}
/**
* Gets the writer {@link Schema} used by {@link #serialize(GenericRecord)}.
*/
public final Schema getWriter() {
return _writer;
}
/**
* Gets the reader {@link Schema} used by {@link #deserialize(byte[])}.
*/
public final Schema getReader() {
return _reader;
}
/**
* Gets the opaque resolver generated by the {@link ResolvingDecoder}
* based on the writer and the reader known to this serializer.
*/
public final Object getResolver() {
return _resolver;
}
}