Midterm Project — Build a Real CLI Tool

2. The Four Tracks — Pick One

Track A — Todo Manager (কাজের তালিকা)

• todo add "Buy rice" --priority high
• todo list — pretty-printed table, sorted by priority
• todo done 3 — marks task 3 complete
• todo rm 3 — deletes task 3
• Persist to ~/.todos.json. Create if missing.

Track B — Weather CLI (আবহাওয়া CLI)

• weather Dhaka — calls a free weather API (e.g. Open-Meteo)
• Uses Java 11 HttpClient — no external HTTP library
• Parses JSON (Jackson, Gson, or hand-rolled)
• Prints temperature, feels-like, humidity, and tomorrow's forecast
• Caches last response to ~/.weather-cache.json for 10 min

Track C — Password Generator (পাসওয়ার্ড জেনারেটর)

• pwgen --length 16 --upper --digits --symbols
• Uses java.security.SecureRandom (never Math.random())
• Reports a simple strength score (bits of entropy)
• Option --count N to produce N passwords
• Option --no-ambig to exclude ambiguous characters (O 0 I l 1)

Track D — CSV Stats (CSV পরিসংখ্যান)

• csvstats sales.csv --col price
• Computes count, min, max, mean, median, stddev for the chosen column
• Uses streams and DoubleSummaryStatistics
• --group-by region option prints per-group stats
• Handles missing/invalid cells gracefully

3. Project Structure and Starter Skeleton

Use Maven. Three to six classes. Below is a runnable skeleton that shows argument parsing, a sub-command dispatch, and a clean exit code on failure. It runs here in the sandbox.

class Main {
    public static void main(String[] args) {
        // simulate: todo add "Buy rice"
        String[] demo = { "add", "Buy rice" };
        int rc = dispatch(demo);
        System.out.println("exit code = " + rc);
    }

    static int dispatch(String[] args) {
        if (args.length == 0) {
            usage();
            return 2;
        }
        String cmd = args[0];
        return switch (cmd) {
            case "add"  -> add(args);
            case "list" -> list();
            case "done" -> done(args);
            default    -> { usage(); yield 2; }
        };
    }

    static int add(String[] a) {
        if (a.length < 2) { System.err.println("need a title"); return 2; }
        System.out.println("added: " + a[1]);
        return 0;
    }
    static int list() { System.out.println("(no items)"); return 0; }
    static int done(String[] a) { System.out.println("done"); return 0; }
    static void usage() {
        System.err.println("Usage: todo [add|list|done|rm] ...");
    }
}

4. Deliverables Checklist

5. Rubric — How You Will Be Scored

6. Common Pitfalls to Avoid

7. Vocabulary