java - How can I Enhance my AddressBook addEntry() method? -

i have address book program [1] adds entry [2] delete entry [3] update/edit entry [4] view entry , [5] view specific entry..

entries stored in array entry[] like:

entry[counter] = new addressbookentry(); 

it runs thing is... want there checking if user's input name used or if user doesn't typed when ask "enter name: "

here's addentry() method:

public void addentry() {      entry[counter] = new addressbookentry();     entry[counter].setname(joptionpane.showinputdialog("enter name: "));     entry[counter].setadd(joptionpane.showinputdialog("enter add: "));     entry[counter].setphoneno(joptionpane.showinputdialog("enter phone no.: "));     entry[counter].setemail(joptionpane.showinputdialog("enter e-mail: "));     counter++; } 

it allows user input entry likes... no checking if name used , if user leave "enter name: " blank still allows user proceed "enter add.: "

here's complete code in main program:

import javax.swing.joptionpane; import javax.swing.jtextarea;  public class addressbook {      private addressbookentry entry[];     private int counter;     private string sname;     private int notfound = 0;      public static void main(string[] args) {         addressbook = new addressbook();         a.entry = new addressbookentry[100];         int option = 0;         try {             while (option != 5) {                 string content = "choose option\n\n"                         + "[1] add entry\n"                         + "[2] delete entry\n"                         + "[3] update entry\n"                         + "[4] view entries\n"                         + "[5] view specific entry\n"                         + "[6] exit";                 option = integer.parseint(joptionpane.showinputdialog(content));                 switch (option) {                     case 1:                         a.addentry();                         break;                     case 2:                         a.deleteentry();                         break;                     case 3:                         a.editentry();                         break;                     case 4:                         a.viewall();                         break;                     case 5:                         a.searchentry();                         break;                     case 6:                         system.exit(1);                         break;                     default:                         joptionpane.showmessagedialog(null, "invalid choice!");                 }             }         }catch(numberformatexception e){             joptionpane.showmessagedialog(null, "please choose number in displayed menu");         }     }      public void addentry() {         entry[counter] = new addressbookentry();         entry[counter].setname(joptionpane.showinputdialog("enter name: "));         entry[counter].setadd(joptionpane.showinputdialog("enter add: "));         entry[counter].setphoneno(joptionpane.showinputdialog("enter phone no.: "));         entry[counter].setemail(joptionpane.showinputdialog("enter e-mail: "));         counter++;     }      public void viewall() {         string addtext = "  name\taddress\tphone no.\te-mail add\n\n";         int nonnull = 0;         (int = 0; < entry.length; i++) {             if (entry[i] != null) {                 addtext = addtext + entry[i].getinfo() + "\n";                 nonnull++;             }             if (nonnull == counter) {                 break;             }         }         joptionpane.showmessagedialog(null, new jtextarea(addtext));     }      public void searchentry() {         sname = joptionpane.showinputdialog("enter name find: ");         searchmethod();     }      public void searchmethod() {         (int = 0; < counter; i++) {             if (entry[i].getname().equals(sname)) {                 joptionpane.showmessagedialog(null, entry[i].getinfo2());                 notfound = 0;                 break;             } else {                 notfound++;             }         }         if (notfound != 0) {             joptionpane.showmessagedialog(null, "name not found!");         }     }      public void editentry() {         sname = joptionpane.showinputdialog("enter name edit: ");         (int = 0; < counter; i++) {             if (entry[i].getname().equals(sname)) {                 entry[i] = new addressbookentry();                 entry[i].setname(joptionpane.showinputdialog("enter new name: "));                 entry[i].setadd(joptionpane.showinputdialog("enter new add: "));                 entry[i].setphoneno(joptionpane.showinputdialog("enter new phone no.: "));                 entry[i].setemail(joptionpane.showinputdialog("enter new e-mail: "));                 notfound = 0;                 break;             } else {                 notfound++;             }         }         if (notfound != 0) {             joptionpane.showmessagedialog(null, "name not found!");         }     }      public void deleteentry() {         sname = joptionpane.showinputdialog("enter name delete: ");         (int = 0; < counter; i++) {             if (entry[i].getname().equals(sname)) {                 joptionpane.showmessagedialog(null, "found!");                 entry[i] = null;                 break;             }         }     } } 

hope can can me new in java , don't add in code checking.
* should add in addentry() method check if name used or no name entered? * need condition in searchmethod()?

an address book tends thing given name, address, , other information.

so falls under general pattern have key (the name) , value (the other information)

when ever see this, want think of using map

so, i'd recommend instead of putting addressbookentry's in array, use map this

map<string, addressbookentry> addressbook = new hashmap<string, addressbookentry>(); 

then when want add new entry do

addressbook.put("john", new addressbookentry()); 

the nice thing map can have 1 entry same person.

so don't have worry happens if put john in book twice. allow 1 in there.