Java if-statement

Question

public void searchKlijenta(KlijentiFormEvent klijentiFormEvent) throws SQLException {

    String nazivK = klijentiFormEvent.getNaziv();
    String adresaK = klijentiFormEvent.getAdresa();
    String gradK = klijentiFormEvent.getGrad();
    String drzavaK = klijentiFormEvent.getDrzava();
    String telefonK = klijentiFormEvent.getTelefon();
    String faxK = klijentiFormEvent.getFax();
    String mailK = klijentiFormEvent.getMail();
    String mobitelK = klijentiFormEvent.getMobitel();
    String oibK = klijentiFormEvent.getOib();
    String ugovorK = klijentiFormEvent.getUgovor();
    String osobaK = klijentiFormEvent.getOsoba();

    if (nazivK.length() == 0) 
        nazivK = null;
    if (adresaK.length() == 0) 
        adresaK = null;
    if (gradK.length() == 0) 
        gradK = null;
    if (drzavaK.length() == 0) 
        drzavaK = null;
    if (telefonK.length() == 0) 
        telefonK = null;
    if (faxK.length() == 0) 
        faxK = null;
    if (mailK.length() == 0) 
        mailK = null;
    if (mobitelK.length() == 0) 
        mobitelK = null;
    if (oibK.length() == 0) 
        oibK = null;
    if (ugovorK.length() == 0) 
        ugovorK = null;
    if (osobaK.length() == 0) 
        osobaK = null;


    klijentiSearchModel.clear();

    String sql = "select * from zavrsni.klijenti where naziv like '"+nazivK+"' or adresa like '"+adresaK+"' or grad like '"+gradK+"' or drzava like '"+drzavaK+"' or telefon like '"+telefonK+"' or fax like '"+faxK+"' or mail like '"+mailK+"' or mobitel like '"+mobitelK+"' or oib like '"+oibK+"' or ugovor like '"+ugovorK+"' or osoba like '"+osobaK+"' ";
    Statement selectStmt = con.createStatement();
    ResultSet result = selectStmt.executeQuery(sql);

    while(result.next()) {
        int id = result.getInt("id");
        String naziv = result.getString("naziv");
        String adresa = result.getString("adresa");
        String grad = result.getString("grad");
        int posBr = result.getInt("posBr");
        String drzava = result.getString("drzava");
        String telefon = result.getString("telefon");
        String fax = result.getString("fax");
        String mail = result.getString("mail");
        String mobitel = result.getString("mobitel");
        String oib = result.getString("oib");
        String ugovor = result.getString("ugovor");
        String osoba = result.getString("osoba");

        KlijentiModelSearch klijentSearch = new KlijentiModelSearch(id, naziv, adresa, grad, posBr, drzava, telefon, fax, mail, mobitel, oib, ugovor, osoba);
        klijentiSearchModel.add(klijentSearch);
    }

    result.close();
    selectStmt.close();

}

Can i write this code shorter? I think of "if" statement?

Perhaps through a while loop?

Method that is use for search some client in database. This method work fane but this if-statement i want write shorter.

Thanks

EDIT SOLVED:

public void traziKlijenta(KlijentiFormEvent klijentiFormEvent) throws SQLException {

    String nazivK = returnNullIfEmptys(klijentiFormEvent.getNaziv());
    String adresaK = returnNullIfEmptys(klijentiFormEvent.getAdresa());
    String gradK = returnNullIfEmptys(klijentiFormEvent.getGrad());
    String drzavaK = returnNullIfEmptys(klijentiFormEvent.getDrzava());
    String telefonK = returnNullIfEmptys(klijentiFormEvent.getTelefon());
    String faxK = returnNullIfEmptys(klijentiFormEvent.getFax());
    String mailK = returnNullIfEmptys(klijentiFormEvent.getMail());
    String mobitelK = returnNullIfEmptys(klijentiFormEvent.getMobitel());
    String oibK = returnNullIfEmptys(klijentiFormEvent.getOib());
    String ugovorK = returnNullIfEmptys(klijentiFormEvent.getUgovor());
    String osobaK = returnNullIfEmptys(klijentiFormEvent.getOsoba());

    klijentiSearchModel.clear();

    String sql = "select * from zavrsni.klijenti where naziv like '%"+nazivK+"%' or adresa like '%"+adresaK+"%' or grad like '%"+gradK+"%' or drzava like '%"+drzavaK+"%' or telefon like '%"+telefonK+"%' or fax like '%"+faxK+"%' or mail like '%"+mailK+"%' or mobitel like '%"+mobitelK+"%' or oib like '%"+oibK+"%' or ugovor like '%"+ugovorK+"%' or osoba like '%"+osobaK+"%' ";
    Statement selectStmt = con.createStatement();
    ResultSet result = selectStmt.executeQuery(sql);

    while(result.next()) {
        int id = result.getInt("id");
        String naziv = result.getString("naziv");
        String adresa = result.getString("adresa");
        String grad = result.getString("grad");
        int posBr = result.getInt("posBr");
        String drzava = result.getString("drzava");
        String telefon = result.getString("telefon");       
        String fax = result.getString("fax");
        String mail = result.getString("mail");
        String mobitel = result.getString("mobitel");
        String oib = result.getString("oib");
        String ugovor = result.getString("ugovor");
        String osoba = result.getString("osoba");

        KlijentiModelSearch klijentSearch = new KlijentiModelSearch(id, naziv, adresa, grad, posBr, drzava, telefon, fax, mail, mobitel, oib, ugovor, osoba);
        klijentiSearchModel.add(klijentSearch);
    }

    result.close();
    selectStmt.close();

}
private String returnNullIfEmptys(String value) {
    if (value == null || value.length() == 0) {
        return null;
    }
    return value;
}

how about nazivK = nazivK.length() == 0 ? null : nazivK and so on? — oruckdeschel
– oruckdeschel, Commented Feb 10, 2017 at 9:06
If your variables were in a list or array instead of separately named, you could do it all in a loop. Alternatively, you could write a method nullIfEmpty and write nazivK = nullIfEmpty(nazivK); etc. — khelwood
– khelwood, Commented Feb 10, 2017 at 9:06
Make a collection of variable if they have same datatypes. Iterate the collection and write your logic — Shubham Chaurasia
– Shubham Chaurasia, Commented Feb 10, 2017 at 9:07
And for the record: such code is the symptom of bad design. Dont just look at this code; step back and have some more experienced people review more of your project. What you are showing here is for sure just the tip of the iceberg ;-) — GhostCat
– GhostCat, Commented Feb 10, 2017 at 9:14

davidxxx · Accepted Answer · 2017-02-10 10:19:20Z

4

With your actual code, @khelwood proposition in your comment question is the best approach.
Other solutions have overhead and change your design without bringing a added value .

public static String returnNullIfEmpty(String value){
   if (value == null || value.length() == 0){
      return null;
   }
     return value;
}

Then you can call it in this way :

nazivK = returnNullIfEmpty(nazivK);
adresaK= returnNullIfEmpty(adresaK);

EDIT

With the edit of your question, you could include processing as the time where you retrieve the value from the klijentiFormEvent object :

String nazivK =  returnNullIfEmpty(klijentiFormEvent.getNaziv());
String adresaK = returnNullIfEmpty(klijentiFormEvent.getAdresa());
...

edited Feb 10, 2017 at 10:19

answered Feb 10, 2017 at 9:24

davidxxx

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3 Comments

Hrvoje Over a year ago

I my declaration of method "public void searchKlijenta(KlijentiFormEvent klijentiFormEvent)" klijentiFormEvent is data from my field(String naziv = nazivField.getText()..), so that your code dont make what i want..check most be before sql statement..null most be in sql statement if if-statement runs..i have form for search clients i database, if textfield for something is empty i dont want to searh in database emtpy field i.e in search form must be typed some text..

Hrvoje Over a year ago

Yes that work now thanks. I have question, what is better? 1. Your solution to call method: telefonK = returnNullIfEmptys(telefonK); or 2. nazivK = (nazivK.length() == 0) ? null : nazivK;

davidxxx Over a year ago

The first one is better because you don't repeat logic. If you have to change it, you have to do it at a single place. Besides in the second solution, you repeat 3 times the nazivK variable. It means that when you add a new control, you have to copy paste an existing instruction and change three time the variable name. It is more error prone.

GhostCat · Accepted Answer · 2017-02-10 09:07:10Z

0

You simply have to put your arrays/lists ... whatever those things are ... into another array or list.

Then you iterate that array/list.

Done.

And hint: your naming could be improved dramatically. Your names should indicate what the "thing" behind the variable actually is.

answered Feb 10, 2017 at 9:07

GhostCat

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Comments

Vlad Bochenin · Accepted Answer · 2017-02-10 09:19:23Z

0

Also you can use Map<String, List<?>> to store your lists/arrays/strings. for example with List:

    Map<String, List<?>> map = new HashMap<>();
    map.put("nazivK", new ArrayList<>());
    map.put("adresaK", new ArrayList<>());
    //.....
    //replace all lists with null
    map.replaceAll((s, list) -> list.isEmpty() ? null : list);

    //or just remove it
    for(Iterator<Map.Entry<String, List<?>>> it = map.entrySet().iterator(); it.hasNext(); ) {
        Map.Entry<String, List<?>> entry = it.next();
        if(entry.getValue().isEmpty()) {
            it.remove();
        }
    }

answered Feb 10, 2017 at 9:19

Vlad Bochenin

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Nayriva · Accepted Answer · 2017-02-10 09:27:12Z

0

As it was suggested by GhostCat, put your values into array/list. You can do for example something like this (I suppose those values are Strings):

/* Order in array nazivK, adresaK, gradK, drzavaK, telefonK,
   faxK, mailK, mobitelK, oibK, ugovorK, osobaK */
   String values[] = new String[11];
   for (String val: values) {
       if (val == null || val.length() == 0) {
           val = null;
       }
   }

answered Feb 10, 2017 at 9:27

Nayriva

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