/**
 * @Title Week 7 Discussion
 * @author Adam Hall
 */
package week7discussion;

import java.util.ArrayList;
import java.util.List;

/**
 *
 * @author adamchall
 */
//Stack is first in last out
class ObjectStack {

    private Object[] myStack;
    private int top;

    public ObjectStack(int maxSize) {
        myStack = new Object[maxSize];
        top = -1;
    }

    void Push(Object input) {
        myStack[++top] = input;
    }

    Object Pop() {
        return myStack[top--];
    }

    boolean isEmpty() {
        return (top == -1);
    }

}

class GenericStack<T> {

    private List<T> myStack;

    public GenericStack() {
        myStack = new ArrayList<>();
    }

    void Push(T input) {
        myStack.add(input);
    }

    T Pop() {
        T returnValue;

        if (myStack.isEmpty() == true) {
            return null;
        }

        returnValue = myStack.get(myStack.size() - 1);
        myStack.remove(myStack.size() - 1);
        return returnValue;

    }

    T Peek() {
        return myStack.get(myStack.size() - 1);

    }

    boolean isEmpty() {
        return myStack.isEmpty();
    }

}

public class Week7Discussion {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
            System.out.println("About to try Generic Stack");

        GenericStack<Double> myDoubleStack = new GenericStack<>();

        myDoubleStack.Push(42.0);

        // Comment this next line out in order to compile, notice it does not compile
        // Because the top is spotted as being not valid at compile time
    //    myDoubleStack.Push("Here is a string!"); // This error is caught at compile time
        myDoubleStack.Push(888.8);

        while (!myDoubleStack.isEmpty()) {
            Object objectValue;
            objectValue = myDoubleStack.Pop();
            System.out.println((double) objectValue); // This is not flagged
        }

        System.out.println("About to try ObjectStack");

        ObjectStack myObjectStack = new ObjectStack(10);

        myObjectStack.Push(42.0);
        // Comment this line out to remove RUNTIME error
        myObjectStack.Push("Here is a string!");
        myObjectStack.Push(888.8);

        try {
            while (!myObjectStack.isEmpty()) {
                Object objectValue;
                objectValue = myObjectStack.Pop();
                System.out.println((double) objectValue); // This is not flagged
            }

        } catch (ClassCastException exception) {
            System.out.println(exception);
            System.out.println("This exception points to a programming error that does not show until runtime!");
        }

    }

}