OperandStack.java

package com.github.HarryHook.coding2017.jvm.engine;

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

public class OperandStack {
    private List<JavaObject> operands = new ArrayList<JavaObject>();

    public void push(JavaObject jo) {
	operands.add(jo);
    }

    public JavaObject pop() {
	int index = size() - 1;
	JavaObject jo = (JavaObject) operands.get(index);
	operands.remove(index);
	return jo;

    }

    public JavaObject top() {
	int index = size() - 1;
	return (JavaObject) operands.get(index);
    }

    public int size() {
	return operands.size();
    }
}