I am making a GUI project in which I need a matrice-type database.
How can I create a class that can store multiple objects in an ArrayList?
1 Answer
I think a better way to do this is to create a user info class to store the information of a particular user like this.
// I made them all public but this might not be a good idea!
class UserInfo {
String user;
String pass;
String secretCode;
}
And you put it into an ArrayList.
ArrayList <UserInfo> InfoList = new ArrayList<UserInfo> ();
Then for your current methods, you can do
// Not so sure what you want to do in this method... so you get to figure out that yourself!
public void userInternalDatabase (UserInfo info) {
this.user = info.user;
this.pass = info.pass;
this.secretCode = info.secretCode;
}
public void addUser(String i, String j, String k) {
UserInfo newUser = new UserInfo();
newUser.user = i;
newUser.pass = j;
newUser.secretCode = k;
InfoList.add(newUser);
}
public Object findUsername(String a)
{
for (int i=0; i <InfoList.size(); i++) {
if (InfoList.get(i).user.equals(a)){
return "This user already exists in our database.";
}
}
return "User is not founded."; // no Customer found with this ID; maybe throw an exception
}
2 Comments
user1799252
Thank you for your help. So, if I want to retrieve the username data, what should I do? Also, would the InfoList have three columns: username, password, and secret code?? Thanks.
cwhsu
you could use InfoList.get(index) which index is an integer to retrieve an UserInfo object, or you could use iterator to search object which has the same info that you're searching for. You can access the data by using InfoList.get(i).user, InfoList.get(i).pass, InfoList.get(i).secretCode. And again note that public variables might not be a good idea!
ArrayList?Userto encapsulate data about users. Once you create a User class, you can create an ArrayList of Users. This is an important concept in Object Oriented Programming.