/*
* Copyright 2011 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 voldemort.serialization.avro;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
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.reflect.ReflectDatumReader;
import org.apache.avro.reflect.ReflectDatumWriter;
import voldemort.serialization.SerializationException;
import voldemort.serialization.SerializationUtils;
import voldemort.serialization.Serializer;
/**
* <p>
* Avro serializer that uses Java reflection to generate schemas and protocols
* for existing classes.
* </p>
*
* <p>
* This API is not recommended except as a stepping stone for systems that
* currently uses Java interfaces to define RPC protocols. For new RPC systems,
* the Avro specific API is preferred. For systems that process dynamic data,
* the Avro generic API is probably best.
* </p>
*
* <p>
* Reflection is supported from either the class, the schema or both.
* <strong>For now we only support the class case.</strong>
* </p>
*
*/
public class AvroReflectiveSerializer<T> implements Serializer<T> {
private final Class<T> clazz;
/**
* Constructor accepting a Java class name under the convention
* java=classname.
*
* @param schemaInfo information on the schema for the serializer
*/
@SuppressWarnings("unchecked")
public AvroReflectiveSerializer(String schemaInfo) {
try {
clazz = (Class<T>) Class.forName(SerializationUtils.getJavaClassFromSchemaInfo(schemaInfo));
} catch(ClassNotFoundException e) {
throw new SerializationException(e);
}
}
public byte[] toBytes(T object) {
ByteArrayOutputStream output = new ByteArrayOutputStream();
Encoder encoder = new BinaryEncoder(output);
ReflectDatumWriter<T> datumWriter = null;
try {
datumWriter = new ReflectDatumWriter<T>(clazz);
datumWriter.write(object, encoder);
encoder.flush();
} catch(IOException e) {
throw new SerializationException(e);
} finally {
SerializationUtils.close(output);
}
return output.toByteArray();
}
public T toObject(byte[] bytes) {
Decoder decoder = DecoderFactory.defaultFactory().createBinaryDecoder(bytes, null);
ReflectDatumReader<T> reader = null;
try {
reader = new ReflectDatumReader<T>(clazz);
return reader.read(null, decoder);
} catch(IOException e) {
throw new SerializationException(e);
}
}
}