Set a Field

In this example, you will learn how you can use DataPipeline to add a new field/column to a dataset and set its value.  You can use this approach to add timestamps and tracking data to all records in a dataset before sending it on for processing and analysis.

Input CSV file

Account,LastName,FirstName,Balance,CreditLimit,AccountCreated,Rating
101,Reeves,Keanu,9315.45,10000.00,1/17/1998,A
312,Butler,Gerard,90.00,1000.00,8/6/2003,B
868,Hewitt,Jennifer Love,0,17000.00,5/25/1985,B
761,Pinkett-Smith,Jada,49654.87,100000.00,12/5/2006,A
317,Murray,Bill,789.65,5000.00,2/5/2007,C

Java Code Listing

package com.northconcepts.datapipeline.examples.cookbook;

import java.io.File;

import com.northconcepts.datapipeline.core.DataReader;
import com.northconcepts.datapipeline.core.StreamWriter;
import com.northconcepts.datapipeline.csv.CSVReader;
import com.northconcepts.datapipeline.job.Job;
import com.northconcepts.datapipeline.transform.SetField;
import com.northconcepts.datapipeline.transform.TransformingReader;

public class SetAField {
    
    public static void main(String[] args) throws Throwable {
        DataReader reader = new CSVReader(new File("example/data/input/credit-balance-01.csv"))
            .setFieldNamesInFirstRow(true);
        
        TransformingReader transformingReader = new TransformingReader(reader);
        
        // Create an 'AccountType' field and set it to 'Personal'
        transformingReader.add(new SetField("AccountType", "Personal"));
        
        Job.run(transformingReader, new StreamWriter(System.out));
    }
    
}

Code walkthrough

1. CSVReader is created corresponding to the input file credit-balance-01.csv.
2. The CSVReader.setFieldNamesInFirstRow(true) method is invoked to specify that the names specified in the first row should be used as field names.
3. A TransformingReader is created to apply one or more transformations to the incoming data sequentially.
4. SetField accepts name and value arguments. It means that a new field called name is created with the default value of value. In addition to these arguments, fieldType and overwrite parameters can also be added to this class's constructor. In the given example, the "AccountType" field is added and set to "Personal".
5.  Data is transferred from the transformingReader to the StreamWriter(System.out) via Job.run() method.

Output

-----------------------------------------------
0 - Record (MODIFIED) {
    0:[Account]:STRING=[101]:String
    1:[LastName]:STRING=[Reeves]:String
    2:[FirstName]:STRING=[Keanu]:String
    3:[Balance]:STRING=[9315.45]:String
    4:[CreditLimit]:STRING=[10000.00]:String
    5:[AccountCreated]:STRING=[1/17/1998]:String
    6:[Rating]:STRING=[A]:String
    7:[AccountType]:STRING=[Personal]:String
}

-----------------------------------------------
1 - Record (MODIFIED) {
    0:[Account]:STRING=[312]:String
    1:[LastName]:STRING=[Butler]:String
    2:[FirstName]:STRING=[Gerard]:String
    3:[Balance]:STRING=[90.00]:String
    4:[CreditLimit]:STRING=[1000.00]:String
    5:[AccountCreated]:STRING=[8/6/2003]:String
    6:[Rating]:STRING=[B]:String
    7:[AccountType]:STRING=[Personal]:String
}

-----------------------------------------------
2 - Record (MODIFIED) {
    0:[Account]:STRING=[868]:String
    1:[LastName]:STRING=[Hewitt]:String
    2:[FirstName]:STRING=[Jennifer Love]:String
    3:[Balance]:STRING=[0]:String
    4:[CreditLimit]:STRING=[17000.00]:String
    5:[AccountCreated]:STRING=[5/25/1985]:String
    6:[Rating]:STRING=[B]:String
    7:[AccountType]:STRING=[Personal]:String
}

-----------------------------------------------
3 - Record (MODIFIED) {
    0:[Account]:STRING=[761]:String
    1:[LastName]:STRING=[Pinkett-Smith]:String
    2:[FirstName]:STRING=[Jada]:String
    3:[Balance]:STRING=[49654.87]:String
    4:[CreditLimit]:STRING=[100000.00]:String
    5:[AccountCreated]:STRING=[12/5/2006]:String
    6:[Rating]:STRING=[A]:String
    7:[AccountType]:STRING=[Personal]:String
}

-----------------------------------------------
4 - Record (MODIFIED) {
    0:[Account]:STRING=[317]:String
    1:[LastName]:STRING=[Murray]:String
    2:[FirstName]:STRING=[Bill]:String
    3:[Balance]:STRING=[789.65]:String
    4:[CreditLimit]:STRING=[5000.00]:String
    5:[AccountCreated]:STRING=[2/5/2007]:String
    6:[Rating]:STRING=[C]:String
    7:[AccountType]:STRING=[Personal]:String
}

-----------------------------------------------
5 records