Replace conditional with polymorphism - nice in theory but not practical

Question

\"Replace conditional with polymorphism\" is elegant only when type of object you\'re doing switch/if statement for is already selected for you. As an example, I have a web

Answer 1

You can store string and corresponding action type somewhere in hash map.

public abstract class BaseAction
{
    public abstract void doSomething();
}

public class ViewAction : BaseAction
{
    public override void doSomething() { // perform a view action here... }
}

public class EditAction : BaseAction
{
    public override void doSomething() { // perform an edit action here... }
}

public class SortAction : BaseAction
{
    public override void doSomething() { // perform a sort action here... }
}


string action = "view"; // suppose user can pass either
                        // "view", "edit", or "sort" strings to you.
BaseAction theAction = null;

theAction = actionMap.get(action); // decide at runtime, no conditions
theAction.doSomething();