package com.mycompany.example;

import com.vertica.sdk.*;

public class RowCountFactory extends ScalarFunctionFactory {
				
    @Override							
    public void getPrototype(ServerInterface srvInterface, ColumnTypes argTypes, ColumnTypes returnType) 				
    {				
        argTypes.addInt();
        argTypes.addInt();
	 returnType.addInt();				
    }				

public class RowCount extends ScalarFunction {
	
    private Integer count;
    private Integer rowCount;
				
	// In the setup method, you look for the rowCount parameter. If it doesn't exist, it is created.
	// Look in the default namespace which is "library," but it could be anything else, most likely "public" if not "library".
	@Override			
       public void setup(ServerInterface srvInterface, SizedColumnTypes argTypes) {
	count = new Integer(0);
	ParamReader pSessionParams = srvInterface.getUDSessionParamReader("library");
	String rCount = pSessionParams.containsParameter("rowCount")?
	pSessionParams.getString("rowCount"): "0";
	rowCount = Integer.parseInt(rCount);
				
    }
  						
    @Override				
    public void processBlock(ServerInterface srvInterface, BlockReader arg_reader, BlockWriter res_writer)
		throws UdfException, DestroyInvocation {				
        do {
		++count;
		long a = arg_reader.getLong(0);
		long b = arg_reader.getLong(1);
			
		res_writer.setLong(a+b);
		res_writer.next();
        } while (arg_reader.next());
    }
	
    @Override			
    public void destroy(ServerInterface srvInterface, SizedColumnTypes argTypes, SessionParamWriterMap udParams){
		rowCount = rowCount+count;
		udParams.getUDSessionParamWriter("library").setString("rowCount", Integer.toString(rowCount));
		srvInterface.log("RowNumber processed %d records", count);
		}
	}
				
    @Override				
    public ScalarFunction createScalarFunction(ServerInterface srvInterface){			
        return new RowCount();			
    }
}