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professional usage of abstract class for translation

Answer 1

A:

If language is not equals to EN or FR then Lang lang will not be initialized. Set it explicitly to new EN() before the if.

rics 2010-09-21 11:50:15

Answer 2

+2 A:

<%
      String language = "EN";
      Lang lang;
      if (language.equals("EN")){
        lang = new EN();
        }
      else if (language.equals("FR")){
        lang = new FR();
      }
    %>

Here it can be the case where language stays un initialized so you need to initialize it

say

Lang lang = null;//or any default value

And to initialize local variable is compulsary

I don't understand the importance of this condition here you are assigning "EN" to language then what is the need of condition?

org.life.java 2010-09-21 11:50:21

Answer 3

A:

Set a default value for the lang variable:

Lang lang = new EN();
 if (language.equals("EN")){
     lang = new EN();
 }
 else if (language.equals("FR")){
    lang = new FR();
 }

gedim 2010-09-21 11:50:48

Answer 4

+1 A:

Change the condition as follows:

if (language.equals("FR")){
    lang = new FR();
}
// add more languages here
// example:
// else if (language.equals("DE")) {
//     lang = new DE();
// }
else {
    lang = new EN();
}

Raoul Duke 2010-09-21 11:51:33

Answer 5

+1 A:

Your code does not cater with the case where language is neither "EN" nor "FR". Pick a default language so that the lang variable is always initialised:

Lang lang;
if (language.equals("EN")){
    lang = new EN();
}
else // default case
    lang = new FR();
}

In addition, instead of declaring one attribute for each string that needs to be translated (e.g. String home) consider declaring a method that will take a "key" as a parameter, and return the corresponding translation for that key. For example, in your JSP you could use something like this:

out.print(lang.getString("home"));

Then have all your Lang subclasses return the proper, translated value for each key.

You might also want to have a look at ResourceBundles.

Grodriguez 2010-09-21 12:04:29

i want to reach the hello variable of fr.java or en.java from the index.jsp page. but code i wrote gives me the value from Lang.java.

ammar 2010-09-21 12:11:54

The code you posted is accessing the `home` variable, not the `hello` variable. The `home` variable only seems to be defined in Lang.java, not in EN.java or FR.java.

Grodriguez 2010-09-21 12:14:14

sorry men,it was my mistake in the question, i edited the code. pleas check it again.

ammar 2010-09-21 12:20:35

Class variables cannot be overriden in subclasses. You can override class methods, but only "hide" class variables. Instead, consider my suggestion of declaring a `getString` method in class `Lang`, then overriding this method in subclasses to return the proper translation for each key.

Grodriguez 2010-09-21 12:35:25

Answer 6

A:

If you wanted to print hello variable, declare that variable in abstract Lang class and initialize in concrete classes.

package mypackage;

abstract public class Lang {
  public String hello= "home page";
}

filename EN.java

package mypackage;

public class EN extends Lang {
   {
      hello = "hello";
   }
}

filename FR.java

package mypackage;

public class FR extends Lang {
     {
      hello = "bonjour";
   }
}

Jaydeep 2010-09-21 12:30:24

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