public class main{


public static void main(String[]args){


        Changer scandiesAway=new Changer();
        scandiesAway.addChange(new Change('ä','a'));
        scandiesAway.addChange(new Change('ö','o'));
        System.out.println(scandiesAway.change("ääliö älä lyö, ööliä läikkyy"));
        }

}




import java.util.ArrayList;

public class Changer {


    ArrayList<Change> changes;
    String word;

    public Changer() {

        this.changes = new ArrayList<Change>();


    }


    public void addChange(Change change) {

        changes.add(change);
    }

    public String change(String s) {


        for (Change iterator : changes) {

            s = iterator.change(s);

        }
        return s;
    }
}




public class Change {


    char fromCharacter;
    char toCharacter;



    public Change(char fromCharacter, char toCharacter){

        this.fromCharacter = fromCharacter;
        this.toCharacter = toCharacter;


    }



    public String change(String word) {

        String newWord = word.replace(fromCharacter, toCharacter);


        return newWord;
    }

    @Override
    public String toString() {
        return "Change{" +
                "fromCharacter=" + fromCharacter +
                ", toCharacter=" + toCharacter +
                '}';
    }
}