Merge ArraList of Objects without dublicates and retaining all filed values from all same objects in Java

Question

I Hava two ArrayList of objects like

ArrayList<Record>  dataSetOne;
ArrayList<Record>  dataSetTwo;

Where Records objects looks like

public class Record{
  private String id;
private String name;
private String HomeAdrress;
private String OfficeAdrress;
}

So, In first ArrayList i.e, dataSetOne i will get record data related home adress details.

public class Record{
  id = emp01;
 name = andy;
 HomeAdrress = mexico;
}

In second ArrayList i.e, dataSetTwo i will get record data related office adress details.

public class Record{
   id = emp01;
   name = andy;
   officeAdrress = california;
}

So the requitrement is i need to merge these two arraylist and combine records with id as primary and get both home and office address like below.

public class Record{
  id = emp01;
   name = andy;
  HomeAdrress = mexico;
   officeAdrress = california;
}

Thanks

Ok, now have you tried something to achieve your goal ? SO it noe a coding service, we may help but not do it full for you — azro, May 05 '20 at 09:09
Iterate through `dataSetOne` and create a [`LinkedHashMap`](https://docs.oracle.com/javase/8/docs/api/java/util/LinkedHashMap.html) keyed by `id`. Then iterate through `dataSetTwo` and use the [`merge()`](https://docs.oracle.com/javase/8/docs/api/java/util/Map.html#merge-K-V-java.util.function.BiFunction-) method that was added in Java 8. — Andreas, May 05 '20 at 09:16

score 1 · Answer 1 · answered May 05 '20 at 09:28

import java.util.*;

/* define your IncompleteRecordErr here */
class IncompleteRecordException extends Exception {
    IncompleteRecordException() {    
        super("Your record is incomplete. Vital data missing!");
    }
}

/* */
class Record {
    public int id;
    public String name;
    public String homeAddress;
    public String officeAdrress;
}

public class App {
    public static void main(String[] args) {
        ArrayList<Record> arrList1 = new ArrayList<>();
        ArrayList<Record> arrList2 = new ArrayList<>();
        /* full your arrLists above with elements */

        ArrayList<Record> merged = new ArrayList<>();
        for(int i = 0; i < arrList1.size(); i++) { // supposed both data lists have same len        
            Record r1 = arrList1.get(i);
            Record r2 = arrList2.get(i);
            Record currentRecord = new Record();
            if(r1.id != 0) currentRecord.id = r1.id; // check for not default value
            else if(r2.id != 0) currentRecord.id = r2.id;
            //else throw new IncompleteRecordException();

            if(r1.name != null) currentRecord.name = r1.name;
            else if(r2.name != null) currentRecord.name = r2.name;
            //else throw new IncompleteRecordException();

            if(r1.homeAddress != null) currentRecord.homeAddress = r1.homeAddress;
            else if(r2.homeAddress != null) currentRecord.homeAddress = r2.homeAddress;
            //else throw new IncompleteRecordException();

            if(r1.officeAdrress != null) currentRecord.officeAdrress = r1.officeAdrress;
            else if(r2.officeAdrress != null) currentRecord.officeAdrress = r2.officeAdrress;
            //else throw new IncompleteRecordException();

            merged.add(currentRecord);
        }
    // now, "merged" should contain your merged data
    }
}

score 0 · Answer 2 · answered May 05 '20 at 10:14

Record class must be :

class Record{
  public int id;
  public String name;
  public String homeAddress;
  public String officeAdrress;
  }

and main function :

public static void main(String[] args) {
    ArrayList<Record> merged = new ArrayList<>();
    Record r;
    for(int i = 0; i < dataSetOne.size(); i++) {
       for(int j = 0; j < dataSetTwo.size(); j++){
         if(dataSetOne.get(i).id == dataSetTwo.get(j).id){
           r = new Record();
           r.id = dataSetOne.get(i).id;
           r.name=dataSetOne.get(i).name;
           r.homeAddress = dataSetOne.get(i).homeAddress;
           r.officeAdrress = dataSetTwo.get(j).officeAdrress;
           merged.add(r);
         }
       }
    }
}

Merge ArraList of Objects without dublicates and retaining all filed values from all same objects in Java

2 Answers2