com.twitter.elephantbird.pig.piggybank.BytesToThriftTuple Maven / Gradle / Ivy
package com.twitter.elephantbird.pig.piggybank;
import java.io.IOException;
import com.twitter.elephantbird.thrift.ThriftBinaryDeserializer;
import org.apache.pig.EvalFunc;
import org.apache.pig.data.DataByteArray;
import org.apache.pig.data.Tuple;
import org.apache.thrift.TBase;
import org.apache.thrift.TDeserializer;
import org.apache.thrift.TException;
import org.apache.thrift.protocol.TBinaryProtocol;
import com.twitter.elephantbird.pig.util.ThriftToPig;
import com.twitter.elephantbird.util.TypeRef;
/**
* This is an abstract UDF for converting serialized Thrift objects into Pig tuples.
* To create a converter for your Thrift class MyThriftClass, you simply need to extend
* BytesToThriftTuple with something like this:
*
* {@code
* public class BytesToSimpleLocation extends BytesToThriftTuple {
*
* public BytesToSimpleLocation() {
* setTypeRef(new TypeRef() {});
* }
* }}
*
*/
public abstract class BytesToThriftTuple> extends EvalFunc {
private final TDeserializer deserializer_ = new ThriftBinaryDeserializer();
private ThriftToPig thriftToTuple_;
private TypeRef typeRef_;
/**
* Set the type parameter so it doesn't get erased by Java. Must be called by the constructor!
*
* @param typeRef
*/
public void setTypeRef(TypeRef typeRef) {
typeRef_ = typeRef;
thriftToTuple_ = ThriftToPig.newInstance(typeRef);
}
@Override
public Tuple exec(org.apache.pig.data.Tuple input) throws IOException {
if (input == null || input.size() < 1) {
return null;
}
try {
T tObj = typeRef_.safeNewInstance();
DataByteArray dbarr = (DataByteArray) input.get(0);
deserializer_.deserialize(tObj, dbarr.get());
return thriftToTuple_.getPigTuple(tObj);
} catch (IOException e) {
log.warn("Caught exception "+e.getMessage());
return null;
} catch (TException e) {
log.warn("Unable to deserialize Thrift object: "+e);
return null;
}
}
}