uni/inf2220/hw2/Main.java

import java.util.ArrayList;
import java.util.Arrays;
import java.io.File;

class Main {
	public static void main(String[] args) {
		if (args.length != 2) {
			System.out.println("Expected 2 arguments");
			System.exit(1);
		}
		String filename = args[0];
		int manpower = Integer.parseInt(args[1]);

		Project p = new Project();
		try {
			p.readFile(new File(filename));
		} catch (Exception ex) {
			System.out.println("Failed to read file "+filename);
			return;
		}

		if (findCycle(p))
			return;

		p.calcTimes();

		System.out.println("\nTasks:");
		p.printTasks();

		System.out.println("\nTimes:");
		p.printTimes(manpower);
	}

	static void printTaskList(ArrayList<Task> l) {
		boolean first = true;

		for (int i = l.size() - 1; i >= 0; --i) {
			Task t = l.get(i);

			// Print arrows for everything but the first task
			if (!first) {
				System.out.print(" -> ");
			} else {
				first = false;
			}

			System.out.print(t.name);
		}
		System.out.println("");
	}

	static boolean findCycle(Project p) {
		ArrayList<Task> l = p.findCycle();

		// We found a cycle
		if (l != null) {
			System.out.println("The project is not realizable.");
			printTaskList(l);
			return true;

		// We found no cycle
		} else {
			System.out.println("The project is realizable.");
			return false;
		}
	}
}