Dependency Injection
a common IoC approach
Inversion of Control
#ruby
puts 'What is your name?'
name = gets
process_name(name)
puts 'What is your quest?'
quest = gets
process_quest(quest) require 'tk'
root = TkRoot.new()
name_label = TkLabel.new() {text "What is Your Name?"}
name_label.pack
name = TkEntry.new(root).pack
name.bind("FocusOut") {process_name(name)}
quest_label = TkLabel.new() {text "What is Your Quest?"}
quest_label.pack
quest = TkEntry.new(root).pack
quest.bind("FocusOut") {process_quest(quest)}
Tk.mainloop()Dependency Injection
- Explanation
A naive example
class MovieLister…
public Movie[] moviesDirectedBy(String arg) {
List allMovies = finder.findAll();
for (Iterator it = allMovies.iterator(); it.hasNext();) {
Movie movie = (Movie) it.next();
if (!movie.getDirector().equals(arg)) it.remove();
}
return (Movie[]) allMovies.toArray(new Movie[allMovies.size()]);
}
A naive example
public interface MovieFinder {
List findAll();
}
class MovieLister…
private MovieFinder finder;
public MovieLister() {
finder = new ColonDelimitedMovieFinder("movies1.txt");
}
Dependency Injection
DI
By Stev Wayne
DI
A brief introduction to dependency injection.
