using Java interfaces
- by mike_hornbeck
I need to create interface MultiLingual, that allows to display object's data in different languages (not data itself, but introduction like "Author", "Title" etc.).
Printed data looks like this :
3 grudnia 1998
10th of June 1924
Autor: Tolkien
Tytul: LoTR
Wydawnictwo: Amazon 2010
Author: Mitch Albom
Title: Tuesdays with Morrie
Publishing House: Time Warner Books 2003
37 360,45 PLN
5,850.70 GBP
3rd of December 1998
10th of June 1924
Author: Tolkien
Title: LoTR
Publishing House: Amazon 2010
Author: Mitch Albom
Title: Tuesdays with Morrie
Publishing House: Time Warner Books 2003
37,360.45 GBP
5,850.70 GBP
Test code looks like this :
public class Main {
public static void main(String[] args){
MultiLingual gatecrasher[]={ new Data(3,12,1998),
new Data(10,6,1924,MultiLingual.ENG),
new Book("LoTR", "Tolkien", "Amazon", 2010),
new Book("Tuesdays with Morrie",
"Mitch Albom", "Time Warner Books",2003,
MultiLingual.ENG),
new Money(1232895/33.0,MultiLingual.PL),
new Money(134566/23.0,MultiLingual.ENG),
};
for(int i=0;i < gatecrasher.length;i++)
System.out.println(gatecrasher[i]+"\n");
for(int i=0;i < gatecrasher.length;i++)
System.out.println(gatecrasher[i].get(MultiLingual.ENG)+"\n");
}
}
So i need to introduce constants ENG, PL in MultiLingual interface, as well as method get(int language) :
public interface MultiLingual {
int ENG = 0;
int PL= 1;
String get(int lang);
}
And then I have class Book. Problem starts with the constructors. One of them needs to take MultiLingual.ENG as argument, but how to achieve that ? Is this the proper way? :
class Book implements MultiLingual {
private String title;
private String publisher;
private String author;
public Book(String t, String a, String p, int y, MultiLingual lang){
}
Or should I treat this MultiLingual.ENG as int variable , that will just change automatically constants in interface?
Second constructor for book doesn't take MultLingual as argument, but following implementation is somehow wrong :
public Book(String t, String a, String p, int y){
Book someBook = new Book(t, a, p, y, MultiLingual m);
}
I could just send int m in place of MultiLingual m but then I will have no control if language is set to PL or ENG.
And finally get() method for Boook but I think at least this should be working fine:
public String get(int lang){
String data;
if (lang == ENG){
data = "Author: "+this.author+"\n"+
"Title: "+this.title+"\n"+
"Publisher: "+this.publisher+"\n";
}
else {
data = "Autor: "+this.author+"\n"+
"Tytul: "+this.title+"\n"+
"Wydawca: "+this.publisher+"\n";
}
return data;
}
@Override
public String toString(){
return "";
}
}
