Cfrgtkky

How can I clone contents of Stringbuilder based on number of records and append record to each row of cloned contents. I'm trying to write data to CSV in way each rows have duplicate columns values repeated by times size of records.

Sample Output CSV should look like.

CN1| CN2| CN3

 1    b    c

 1    d    f

 2    g    h

Here's sample Java Code I'm using

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;



public class CSVWrite {

public static Map<String, List<Records>> getData() {



    Map<String, List<Records>> fields = new HashMap<>();



    List<Records> records_1 = new ArrayList<>();



    Records sample_1 = new Records();

    sample_1.setName("b");

    sample_1.setId("c");



    Records sample_2 = new Records();

    sample_2.setName("d");

    sample_2.setId("f");



    records_1.add(sample_1);

    records_1.add(sample_2);



    List<Records> records_2 = new ArrayList<>();



    Records sample_3 = new Records();

    sample_1.setName("g");

    sample_1.setId("h");



    records_2.add(sample_3);



    fields.put("1", records_1);

    fields.put("2", records_2);



    return fields;

}



public static void main(String args) {

    CSVWrite write = new CSVWrite();

    String csvString = write.getCsvString();

    String expectedString = "1,b,cn" + "1,d,fn" + "2,g,h";

    System.out.println(csvString.equals(expectedString));

}



public String getCsvString() {

    Map<String, List<Records>> fields = CSVWrite.getData();

    StringBuilder sb = new StringBuilder();



    for (Map.Entry<String, List<Records>> entry : fields.entrySet()) {

        sb.append(entry.getKey());

        List<Records> records = entry.getValue();



        for (int i = 0; i < records.size(); i++) {

            // how to clone contents of sb repeated times based on records size and append

            // record items to all.

        }

    }

    return sb.toString();

}

}

First, there is an error I think, this code look weird. The var sample_3 is built but not correctly populated:

Records sample_3 = new Records();

sample_1.setName("g");

sample_1.setId("h");

It should be:

Records sample_3 = new Records();

sample_3.setName("g");

sample_3.setId("h");

Finally, there is no need to clone anything to achieve the desired result, simply rewrite getCsvString() like this:

public String getCsvString() {

    Map<String, List<Records>> fields = CSVWrite.getData();

    StringBuilder sb = new StringBuilder();



    for (Map.Entry<String, List<Records>> entry : fields.entrySet()) {

        List<Records> records = entry.getValue();



        for (Records record : records) {

            sb.append(entry.getKey());

            sb.append(",").append(record.getName());

            sb.append(",").append(record.getId());

            sb.append("n");

        }

    }

    return sb.toString();

}

Those 2 corrections will generate output:

1,b,c

1,d,f

2,g,h