JAVA unique string username Array or list or ArrayList
I am newbie to JAVA
I need to maintain a list of UNIQUE connected usernames. I guess something like this snippet:
users = new something; // array ? Lists ? Iterator ?
function check_user_exist(newUserNa
if (users.indexOf(newUserName
// something like this ? This is DELPHI like !
}
The Goal is to maintain a array (lists ? Objects ? ArrayLists ?) of UNIQUE usernames, and CHECK if the username is already present in this array
userName are Strings and not Objects
I need to maintain a list of UNIQUE connected usernames. I guess something like this snippet:
users = new something; // array ? Lists ? Iterator ?
function check_user_exist(newUserNa
if (users.indexOf(newUserName
// something like this ? This is DELPHI like !
}
The Goal is to maintain a array (lists ? Objects ? ArrayLists ?) of UNIQUE usernames, and CHECK if the username is already present in this array
userName are Strings and not Objects
ASKER
ok
But how to declare list ?
list=new WHAT ?
But how to declare list ?
list=new WHAT ?
if you use a Set you dont need to check if it is availabe because Set automatically wont insert if it has already inserted
users = new HashSet<String>()
but please note this is only works if you add string if you want to add any other object you should implement two methods "equals()" and "hashCode()" so the Sit structure will work fine
users = new HashSet<String>()
but please note this is only works if you add string if you want to add any other object you should implement two methods "equals()" and "hashCode()" so the Sit structure will work fine
Set users = new HashSet();
>>connected usernames
What do you mean by that?
What do you mean by that?
I think he means the users that authenticated by his system and a session has been created for them
for a simple sample;
public static void addUser(ArrayList list, String user) {
if (!list.contains(user))
list.add(user);
}
public static boolean checkUser(ArrayList list, String user) {
return (list.contains(user) ? true : false);
}
public static void main(String[] args) {
ArrayList list = new ArrayList();
addUser(list, "xxx");
if (checkUser(list, "xxx"))
System.out.print("yes");
else
System.out.print("no");
}
public static void addUser(ArrayList list, String user) {
if (!list.contains(user))
list.add(user);
}
public static boolean checkUser(ArrayList list, String user) {
return (list.contains(user) ? true : false);
}
public static void main(String[] args) {
ArrayList list = new ArrayList();
addUser(list, "xxx");
if (checkUser(list, "xxx"))
System.out.print("yes");
else
System.out.print("no");
}
private List<String> list = new ArrayList<String();
public void add(String name)
{
if (!list.contains(name))
{
list.add(name);
}
}
public void add(String name)
{
if (!list.contains(name))
{
list.add(name);
}
}
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{
if (!list.contains(name))
{
list.add(name);
}
}