命令模式Command

public class CommandQueue {

	interface Command {
		void execute();
	}

	static class DomesticEngineer implements Command {
		public void execute() {
			System.out.println("take out the trash");
		}
	}

	static class Politician implements Command {
		public void execute() {
			System.out
					.println("take money from the rich, take votes from the poor");
		}
	}

	static class Programmer implements Command {
		public void execute() {
			System.out.println("sell the bugs, charge extra for the fixes");
		}
	}

	public static List produceRequests() {
		List queue = new ArrayList();
		queue.add(new DomesticEngineer());
		queue.add(new Politician());
		queue.add(new Programmer());
		return queue;
	}

	public static void workOffRequests(List queue) {
		for (Iterator it = queue.iterator(); it.hasNext();)
			((Command) it.next()).execute();
	}

	public static void main(String[] args) {
		List queue = produceRequests();
		workOffRequests(queue);
	}
}