Advanced Java (2160707)

What is Dependency Injection

• Dependency Injection (DI) is a design pattern that removes the dependency from the programming code so that it can be easy to manage and test the application.
• Dependency Injection makes our programming code loosely coupled
• DI is a concept of injecting anobject into a class rather than explicitly creating object in a class, since IoC container injects object into class during runtime
• Example:Standard code without Dependency Injection
  • public class TextEditor
    {
        private SpellChecker spellChecker;
        public TextEditor()
        {
        spellChecker = new SpellChecker();
        }
    }
• Example:Code with Dependency Injection
  • public class TextEditor
    {
        private SpellChecker spellChecker;
        public TextEditor(SpellChecker spellChecker)
        {
        this.spellChecker = spellChecker;
        }
    }