Storing the ArrayList data into Object in the given format

Question

CompanyData class contains variable

List<Division> Divisions

Division class contains variables.

String Id,String Name,List<SubD> subD

SubD Class contains

String subId,String subName

Below method prints List

List<Info> dataList = daoImpl.getData(requestId);

Ex: [{"Id":01,"Name":XYZ,"subId":"123","subName":"ABC"},{"Id":01,"Name":XYZ,"subId":"456","subName":"DEF"}]

I am iterating the list using foreach loop:

List<Division> divisionsList = new ArrayList<>();

CompanyData companydata = new ComapanyData();

dataList.stream().forEach(e -> {
Division divisions = new Division();
List<SubD> subList = new ArrayList<>();
SubD subd = new SubD();
divisions.setId(e.get_id());
divisions.setName(e.get_name());
subd.setSubId(e.getSub_id());
subd.setSubName(e.getSub_name());
subList.add(subd);
divisions.setSubD(subList);
divisionsList.add(divisions);
});

The above code prints the data in the below format:

      "divisions": [
            {
                "Id": "01",
                "Name": "XYZ",
                "sub": [
                    {
                        "subId": "123",
                        "subName": "ABC"
                    }
                ]
            },
            {
                "Id": "01",
                "Name": "XYZ",
                "sub": [
                    {
                        "subId": "456",
                        "subName": "DEF"
                    }
                ]
            }
        ]

But is there a way to print the data in the below format If the Id is same the it should print it in the same sub List.

    divisions": [
        {
            "Id": "01",
            "Name": "XYZ",
            "sub": [
                {
                    "subId": "123",
                    "subName": "ABC"
                },
                {
                    "subId": "456",
                    "subName": "DEF"
                }
            ]
        }
    ]

score 0 · Answer 1 · answered May 16 '20 at 11:19

You are missing hashcode and equals method.

There is no way for you to directly identify whether your list already contains the division.

Add the below in your Division class.

 @Override 
 public boolean equals(Object o) {
    if (this == o)
        return true;
    if (o == null || getClass() != o.getClass())
        return false;

    Division div = (Division) o;

    return id != null ? s.equals(div.id) : div.id == null;
}


@Override 
public int hashCode() {
    return id != null ? id.hashCode() : 0;
}

Refer for more information

And one more thing:

If you are doing List<SubD> subList = new ArrayList<>(); inside loop, it's wrong. You should have getter, setter for list and use that to add item to it.

Something like if sublist of division object is empty, create a list and add item to it. Else add item to it.

To avoid duplicated values, you need to do the same for SubD class also.

Storing the ArrayList data into Object in the given format

1 Answers1