Which Java Design Pattern fits best for if-else statement including loop?

Question

I have a use case with 7-8 if else. Sample use case:

 String type;
 List < Entity > entityList;


 if (type.equals(\"A\")) {
    ClassA a = new ClassA();
          


        

Answer 1

A factory implementation could look like this:

public class WidgetFactory {
    public static void main(String[] args) {
        String type = "A";
        List entityList = new ArrayList<>();

        Widget widget = WidgetFactory.createWidget(type);
        widget.performTask();
        for (Entity e : entityList) {
            widget.performTaskOnEntity(e);
        }
    }

    private static Widget createWidget(String type) {
        switch (type) {
            case "A":
                return new ClassA();
            case "B":
                return new ClassB();
            default:
                throw new IllegalArgumentException("Unknown type: " + type);
        }
    }

    private interface Widget {
        void performTask();
        void performTaskOnEntity(Entity entity);
    }

    private static class ClassA implements Widget {
        public void performTask() { }
        public void performTaskOnEntity(Entity entity) { }
    }

    private static class ClassB implements Widget {
        public void performTask() { }
        public void performTaskOnEntity(Entity entity) { }
    }

    private static class Entity {
    }
}