8.2 Imagine you have a call center with three levels of employees: respondent, manager, and director. An incoming telephone call must be first allocated to a respondent who is free. If the respondent can't handle the call, he or she must escalate the call to a manager. If the manager is not free or not able to handle it, then the call should be …

CC150 8.2 callCenter.java

/* Title:   CC150 8.2 callCenter
 * Time:    20140115
 * Creator: blindchaser
 * Time Complexity: 
 * Space Complexity:
 * 优空间解法
 * 优时间解法：
 * 心得： 可以跑
 * 		 
 *       
 */

package chapter_8;

import java.util.ArrayList;
import java.util.Stack;

public class callCenter {
	
	static ArrayList<Employee> respondents = new ArrayList<Employee>();
	static ArrayList<Employee> managers = new ArrayList<Employee>();
	static ArrayList<Employee> directors = new ArrayList<Employee>();
	static Stack<Employee> stack = new Stack<Employee>();

	public static void main(String args[]) {
		createStaff();
		respondents.get(0).status = false;
		managers.get(0).status = false;
		directors.get(0).status = false;
		directors.get(1).status = false;
		Call c1 = new Call(0,8);
		Call c2 = new Call(1,10);
		Call c3 = new Call(2,30);
		System.out.println(handleCall(c1));
		System.out.println(handleCall(c2));
		System.out.println(handleCall(c3));
		
		

	}

	private static void createStaff() {

		for (int i = 0; i < 30; i++) {
			Employee e = new Employee(i, i, true);
			if (i < 10)
				respondents.add(e);
			else if (10 <= i && i < 20)
				managers.add(e);
			else
				directors.add(e);
		}
	}

	private static String handleCall(Call c) {
		String str = "";
		// 先找到一个空的respondents;
		for (Employee e : respondents) {
			if (e.status == true) {
				stack.add(e);
				e.status = false;
				break;
			}
		}

		if (c.hardLevel < 10)
			return str += "Respondent " + stack.peek().number
					+ " handled the call";

		// 若难度过大，forward给manager
		else if (c.hardLevel >= 10 && c.hardLevel < 20) {
			for (Employee e : managers) {
				if (e.status == true) {
					stack.pop().status = true;
					stack.add(e);
					e.status = false;
					return str = "Manager " + stack.peek().number
							+ " handled the call";
				}
			}
		}
		// 难度再过大，forward给director
		for (Employee e : directors) {
			if (e.status == true) {
				stack.pop().status = true;
				stack.add(e);
				e.status = false;
				return str = "Director " + stack.peek().number
						+ " handled the call";
			}
		}

		return str = "System is busy, please wait";
	}

	private static class Employee {
		int number;// 0-9 are respondents; 10-19 are managers; 20-29 are//
					//directors;
		int level;
		boolean status;

		public Employee(int num, int level, boolean status) {
			this.number = num;
			this.level = level;
			this.status = status;
		}

	}

	private static class Call {
		int caller;
		int hardLevel;

		public Call(int caller, int hardLevel) {
			this.caller = caller;
			this.hardLevel = hardLevel;
		}

	}

}