Question

I have code:

    List<ModelMap> nameCustomer = new ArrayList<ModelMap>();

    for (int i=1;i<150;i++) {
                    ModelMap map = new ModelMap();
                    map.put("name", "nazwa " + i);
                    map.put("surname", "nazwisko " + i);
                    map.put("number", "123 ");
                    nameCustomer.add(map);
                }

            ModelMap[] result = new ModelMap[nameCustomer.size()];
            ModelMap[] rowsArray = nameCustomer.toArray(result);

How can I sort nameCustomer (or rowsArray) by surname or number?

Answer 1

You can use the Collections.sort(nameCustomer, comparator) method to sort your list. For that you have to write the code for your Comparator.The code for Comparator will be –

public Comparator<ModelMap> getComparator(final String sortBy){
   if ("surname".equals(sortBy)) {
   return new Comparator<ModelMap>() {
   @Override int compare(ModelMap m1, ModelMap m2) 
    return m1.getSurname().compareTo(m2.getSurname());
   }};} 
     else if (condition) {// ...  }
      else {
        throw new IllegalArgumentException("invalid sort field '" + sortBy + "'"); }
       }

I am assuming that you have a getSurname method written in your ModelMap class to get the surname. If not then write it to make the above code work.

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