Hack#48

ToTuple.java

package org.hadoophacks.pig;

import org.apache.pig.EvalFunc;
import org.apache.pig.data.Tuple;
import org.apache.pig.backend.executionengine.ExecException;
import java.io.IOException;
import org.apache.pig.data.TupleFactory;
import org.apache.pig.data.DataType;
import org.apache.pig.impl.logicalLayer.schema.Schema;

public class ToTuple extends EvalFunc<Tuple>{
    
    private TupleFactory tupleFactory = TupleFactory.getInstance();
    
    public Tuple exec(Tuple input)throws IOException{

	if(input == null || input.size() == 0){
	    return null;
	}
      
	try{

	    int size = input.size();
	    Tuple output = tupleFactory.newTuple(size);
	    
	    for(int i = 0;i < size;i++){
		output.set(i , input.get(i));
	    }

	    return output;
	}
	catch(ExecException e){
	    throw new IOException(e);
	}
    }
    
    public Schema outputSchema(Schema input){
	try{
	    Schema tupleSchema = new Schema();

	    int numFields = input.size();

	    for(int i = 0;i < numFields;i++){
		tupleSchema.add(input.getField(i));
	    }

	    return new Schema(new Schema.FieldSchema("col0" , tupleSchema , DataType.TUPLE));
	}catch(Exception e){
	    return null;
	}
    }
}