Building a stock market monitoring application

Our stock market program will consist of three main components:

• A function simulating an external service from which we can query the current price—this would likely be a network call in a real setting

• A scheduler that polls the preceding function at a predefined interval

• A display function responsible for updating the screen

We'll start by creating a new leiningen project, where the source code for our application will live. Type the following on the command line and then switch into the newly created directory:

lein new stock-market-monitor
cd stock-market-monitor

As we'll be building a GUI for this application, go ahead and add a dependency on Seesaw to the dependencies section of your project.clj:

[seesaw "1.4.4"]

Next, create a src/stock_market_monitor/core.clj file in your favorite editor. Let's create and configure our application's UI components:

(ns stock-market-monitor.core
  (:require [seesaw.core :refer :all])
  (:import (java.util.concurrent...