/*
* Copyright © 2014 Cask Data, 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 co.cask.tigon.sql.io;
import co.cask.tigon.internal.io.DatumReader;
import co.cask.tigon.internal.io.ReflectionDatumReader;
import co.cask.tigon.internal.io.ReflectionSchemaGenerator;
import co.cask.tigon.internal.io.Schema;
import co.cask.tigon.internal.io.UnsupportedTypeException;
import co.cask.tigon.io.Decoder;
import com.google.common.reflect.TypeToken;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
/**
* POJOCreator
* This class converts incoming byte records into POJOs of the output class type
*/
public class POJOCreator {
private static final Logger LOG = LoggerFactory.getLogger(POJOCreator.class);
private final Schema schema;
private final DatumReader outputGenerator;
private final Class<?> outputClass;
/**
* Constructor for the POJOCreator
* @param outputClass Class type to be generated by this {@link co.cask.tigon.sql.io.POJOCreator} object
* @param schema {@link co.cask.tigon.sql.flowlet.StreamSchema} of the incoming data record
* @throws UnsupportedTypeException if the {@link co.cask.tigon.internal.io.ReflectionDatumReader} cannot
* instantiate an object of type outputClass
*/
public POJOCreator(Class<?> outputClass, Schema schema) throws UnsupportedTypeException {
this.schema = schema;
this.outputClass = outputClass;
this.outputGenerator = new ReflectionDatumReader(new ReflectionSchemaGenerator().generate(outputClass, false),
TypeToken.of(outputClass));
}
/**
* This function is called for each incoming byte record.
*
* @param decoder The decoder that encapsulates the byte[] data record
* @return Map of method and the input parameter objects
* @throws java.io.IOException if the {@link co.cask.tigon.internal.io.ReflectionDatumReader} cannot decode incoming
* data record
*/
public Object decode(Decoder decoder) throws IOException {
try {
return outputGenerator.read(decoder, schema);
} catch (IOException e) {
LOG.error("Cannot instantiate object of type {}", outputClass.getName(), e);
throw e;
}
}
}