In JAVA, say I have a string variable:
String x = "CoolClass";
And I have a class called CoolClass with a working constructor. How could I create an object of CoolClass, using the variable x, instead of typing CoolClass itself.
(I need to do this because x will be given by the user and read in by Scanner, and depending on their input, a different object/class will be constructed accordingly).
Class.forName(x).newInstance()
would work, though reflection can be tricky and dangerous. Can you tell us what you're actually trying to do?
Map<String, AnimalFactory>. This'll work, though.This task requires reflection -- Class.forName(x).newInstance().
You might want to use a different design method. Why is the user typing in the desired class?
Animal class, then have the user input the type and store it as a local variable. Creating different classes for different animals seems like overkill, especially since you'll need to call the same methods on all of them.Scanner kbReader = new Scanner(System.In)
String animalType = kbReader.nextLine();
Animal animal; //assume that Lion, Tiger, and Bear inherit Animal
if(animalType.equals("Lion")
{
animal = new Lion();
}
else if(animalType.equals("Tiger")
{
animal = new Tiger();
}
else if(animalType.equals("Bear")
{
animal = new Bear();
}
This is without using reflection of any sort.
You should use Class.forName(x).newInstance() if your class has default constructor. If the constructor is expected to receive parameters use Class.forName(x).getConstructor(YOUR PARAMETER TYPES).newInstance(YOUR ARGUMENTS)
