Dependency Injection

Instead of worrying about your objects dependencies you can let the IoC container inject them in your instances.

Dependency Injection through constructor:

public interface LoggerDAO {
    // contract methods
}
 
public class JdbcLoggerDAO implements LoggerDAO {
    // contract methods
}

public interface Logger{
    // methods implementation
}
 
public class DatabaseLogger implements Logger {
     
    private final LoggerDAO loggerDAO; // DatabaseLogger depends on LoggerDAO
     
    public DatabaseLogger(LoggerDAO loggerDAO) {
        this.loggerDAO = loggerDAO;
    }
     
    // methods implementation
}
 
Container c = new MentaContainer();
c.ioc(LoggerDAO.class, JdbcLoggerDAO.class); 
c.ioc(Logger.class, DatabaseLogger.class).addConstructorDependency(LoggerDAO.class);
Logger logger = c.get(Logger.class); // Logger will come with its dependency LoggerDAO

You can also instantiate any object with the components present in the container:

public class MyClass {
	
	private final Logger logger;
	
	public MyClass(Logger logger) {
		this.logger = logger;
	}
	
	// ...
}

MyClass myClass = c.instantiate(MyClass.class); // DatabaseLogger will be injected through constructor




Dependency Injection through setter:

public interface LoggerDAO {
    // contract methods
}

public class JdbcLoggerDAO implements LoggerDAO {
    // contract methods
}

public interface Logger{
    // methods implementation
}
 
public class DatabaseLogger implements Logger {
     
    private LoggerDAO loggerDAO; // DatabaseLogger depends on LoggerDAO
     
    public void setLoggerDAO(LoggerDAO loggerDAO) {
    	this.loggerDAO = loggerDAO;
    }
    
    // methods implementation
}
 
Container c = new MentaContainer();
c.ioc(LoggerDAO.class, JdbcLoggerDAO.class); 
c.ioc(Logger.class, DatabaseLogger.class).addPropertyDependency(LoggerDAO.class);
Logger logger = c.get(Logger.class); // Logger will come with its dependency LoggerDAO

You can also inject the components present in the container inside any object:

public class MyClass {
	
	private Logger logger;
	
	public void setLogger(Logger logger) {
		this.logger = logger;
	}
	
	// ...
}
MyClass myClass = new MyClass();
c.inject(myClass); // DatabaseLogger will be injected through setter