Example: One query throws the next result set:

Name | Age | Grand Total

• John Smith, 45, 1000
• John Smith, 56, 800
• John Smithers, 34, 500
• John Smyth, 56, 500
• John Smyth, 56, 1100

I want to separate this arraylist into three, and store them in a hashmap where the key is the client name.

I was thinking something like

Arraylist<Row> rows = dao.getClientActivity();
Map map = new HashMap<Clients Name, Clients Row>();
Arraylist<Row>  = null;

for (Row row : rows){

    if (map.get(row.clientName) == null) list = new ArrayList<Row>();

    list.add(row);

    if(map.get(row.clientName) == null) map.put(row.clientName, list);

}

The list will always be sorted by name.

Take the upper snippet as pseudo code, I don't have coding programs at home, I just got that off the top of my head, I think I tested something like that this friday but it only printed on row;

I don't know if there's a better way to do this, but this is the first thing I come up with.

Your map declaration should be as follows (assuming Row.clientName is String):

Map<String, List<Row>> map = new HashMap<String, List<Row>>();

And the for loop should look like as follows:

for (Row row : rows){
    /*Get the list of rows for current client name.*/
    List<Row> currRows = map.get(row.clientName);
    if (currRows == null) {/*If not list exists for*/
        currRows = new ArrayList<Row>(); /*create a new one*/
        map.put(row.clientName, currRows); /*and put it in the map*/
    }
    currRows.add(row);/*add the current row to the list*/
}