**底部的新编辑信息**
我创建了一个模拟电子技术支持系统的技术支持计划。它应该通过票证具有客户端请求支持并将其分配给适当的代理。它有四个类（客户端，代理，票证和实际的技术支持系统）。
门票类：
/**
* Ticket.java
*
* This class is part of Programming
* Assignment 6 - Tech Support System
* for CS1440 Summer 2014.
*
* @author Brandon C. Eason
* @author
* @version
*/
/**
* This class represents a support ticket
* in the tech support ticket.
*/
public class Ticket
{
//the number of minutes for resolving a premium ticket
private static final int PREMIUM = 30;
//the number of minutes for resolving a basic ticket
private static final int BASIC = 60;
//the number of tickets generated
private static int ticketNumber;
//the ticket id, built from the current date and ticket number
private String id;
//the problem description
private String description;
//the number of minutes since the ticket was entered
private int minutes;
//the client that requested this ticket
private Client requester;
//the agent assigned to this ticket
private Agent solver;
/**
* Fully parameterized constructor for Ticket.
*
* @param date - the date this ticket was created
* @param description - this ticket's problem description
* @param minutes - the number of minutes since this ticket was entered
* @param requester - the client that requested this ticket
*/
public Ticket(String date, String description, int minutes,
Client requester)
{
ticketNumber++;
id = date + "-" + ticketNumber;
this.description = description;
this.minutes = minutes;
this.requester = new Client(requester);
}
/**
* Accessor for ticket number.
*
* @return the number of tickets generated
*/
public static int getNumTickets()
{
return ticketNumber;
}
/**
* Accessor for id.
*
* @return this ticket's id
*/
public String getID()
{
return id;
}
/**
* Accessor for description.
*
* @return this ticket's description
*/
public String getDescription()
{
return description;
}
/**
* Accessor for minutes.
*
* @return the number of minutes since this ticket was entered
*/
public int getMinutes()
{
return minutes;
}
/**
* Accessor for the Client requesting the ticket.
*
* @return a copy of the Client requesting this ticket
*/
public Client getClient()
{
return requester;
}
/**
* Assign this ticket to an agent. The method makes a copy of the
* Agent parameter and sets the solver field to that copy.
*
* @param solver - the agent this ticket is assigned to
*/
public void setAgent(Agent solver)
{
String name = solver.getName();
String id = solver.getID();
String specialty = solver.getSpecialty();
int time = solver.getTime();
solver = new Agent(name, id, specialty, time);
}
/**
* Determine the minutes this ticket is overdue.
* Basic service level clients should have their
* tickets resolved within 60 minutes. Premium
* service level clients should have their tickets
* resolved within 30 minutes.
*
* @return the number of minutes the ticket is overdue
*/
public int timeOverdue()
{
int timeOverdue;
if(requester.hasPremium())
{
timeOverdue = (PREMIUM - this.minutes);
}
else
{
timeOverdue = (BASIC - this.minutes);
}
return timeOverdue;
}
/**
* Return a string predicting the resolution time of the ticket.
*
* @return a prediction of the resolution time
*/
public String prediction()
{
String predict = "Resolution Time: ";
int minutes = timeOverdue() + solver.getTime();
if (minutes > 0)
{
predict += minutes + " minutes behind schedule";
}
else if (minutes < 0)
{
predict += Math.abs(minutes) + " minutes ahead of schedule";
}
else
{
predict += "On time";
}
return predict;
}
/**
* Determine whether this ticket is overdue.
*
* @return true if this ticket is overdue
*/
public boolean isOverdue()
{
return timeOverdue() > 0;
}
/**
* Build a string representation of this ticket.
*
* @return this ticket's data
*/
public String toString()
{
//begin with id and description
String data = "ID#: " + getID();
data += "\r\nProblem: " + getDescription();
//add time overdue, if any
if (isOverdue())
{
data += "\r\nOverdue: " + timeOverdue() + " minutes";
}
//add client data
data += "\r\n------------";
data += "\r\nRequested by\r\n";
data += "------------\r\n";
data += requester;
//add agent data
data += "\r\n-----------";
data += "\r\nAssigned to\r\n";
data += "-----------\r\n";
data += solver;
//add projected resolution time
data += "\r\n" + prediction();
return data;
}
/**
* Determine if this ticket is a duplicate of another.
* Tickets are duplicates if they have the same description
* and Client.
*
* @param other - the other Ticket
* @return true if this ticket is a duplicate of the other
*/
public boolean equals(Ticket other)
{
if(description.equals(other.description) && requester.equals(other.requester))
{
return true;
}
else
{
return false;
}
}
}
代理类：
/**
* Agent.java
*
* This class is part of Programming
* Assignment 6 - Tech Support System
* for CS1440 Summer 2014.
*
* @author Brandon C. Eason
* @author
* @version
*/
/**
* This clas represents an agent profile
* in the tech support system.
*/
public class Agent
{
//the agent's name
private String name;
//the agent's id number
private String id;
//the agent's support specialty
private String specialty;
//the agent's average turnaround time in whole minutes
private int time;
/**
* Fully parameterized constructor for Agent.
*
* @param name - this agent's name
* @param id - this agent's id number
* @param specialty - this agent's support specialty
* @param time - this agent's average turnaround time in minutes
*/
public Agent(String name, String id, String specialty, int time)
{
this.name = name;
this.id = id;
this.specialty = specialty;
this.time = time;
}
/**
* Create a copy of this Agent.
*
* @return a new Agent that is a copy of this one
*/
public Agent copy()
{
Agent copyAgent = new Agent(name, id, specialty, time);
return copyAgent;
}
/**
* Accessor for name.
*
* @return this agent's name
*/
public String getName()
{
return name;
}
/**
* Accessor for id number.
*
* @return this agent's id number
*/
public String getID()
{
return id;
}
/**
* Accessor for specialty.
*
* @return this agent's support specialty
*/
public String getSpecialty()
{
return specialty;
}
/**
* Accessor for average turnaround time.
*
* @return this agent's average turnaround time
*/
public int getTime()
{
return time;
}
/**
* Builds a string representation of this agent's data.
*
* @return this agent's data
*/
public String toString()
{
String str = "Agents's name: " + this.name
+ "/nAgent's ID: " + this.id
+ "/nSupport specialty: " + this.specialty
+ "/nAverage service time:" + this.time;
return str;
}
}
客户端类：
/**
* Client.java
*
* This class is part of Programming
* Assignment 6 - Tech Support System
* for CS1440 Summer 2014.
*
* @author Brandon C. Eason
* @author
* @version
*/
/**
* This class represents a client profile in
* the tech support system with information
* about the client and the client's
* computer system.
*/
public class Client
{
//the client's full name
private String name;
//the client's phone number
private String phone;
//the client's computer type
private String computer;
//true if a premium client
private boolean premium;
/**
* Fully parameterized constructor for
* Client.
*
* @param name - this client's name
* @param phone - this client's phone number
* @param computer - this client's computer type
* @param premium - whether client has premium service
*/
public Client(String name, String phone, String computer, boolean premium)
{
this.name = name;
this.phone = phone;
this.computer = computer;
this.premium = premium;
}
/**
* Constructor for when computer type is not specified.
*
* @param name - this client's name
* @param phone - this client's phone
* @param premium - whether client has premium service
*/
public Client(String name, String phone, boolean premium)
{
this(name, phone, "Unspecified", premium);
}
/**
* Constructor that creates a copy of the Client passed in.
*
* @param object - the client to be copied
*/
public Client(Client object)
{
name = object.name;
computer = object.computer;
phone = object.phone;
premium = object.premium;
}
/**
* Accessor for name.
*
* @return this client's name
*/
public String getName()
{
return name;
}
/**
* Accessor for phone.
*
* @return this client's phone number
*/
public String getPhone()
{
return phone;
}
/**
* Accessor for computer type.
*
* @return this client's computer type
*/
public String getComputer()
{
return computer;
}
/**
* Determine if this client receives
* premium service.
*
* @return true if this client receives premium service.
*/
public boolean hasPremium()
{
return premium;
}
/**
* Builds a printable String representation of
* this client's data.
*
* @return this client's data
*/
public String toString()
{
String service;
if(this.premium)
{
service = "Premium";
}
else
{
service = "Basic";
}
String str = "Client's name: " + this.name
+ "/nClient's phone: " + this.phone
+ "/nCSystem type: " + this.computer
+ "/nService:" + service;
return str;
}
/**
* Determine if this Client is the same as another.
* Client's are equal if they have the same name,
* phone number, computer type, and service level.
*
* @param other - the other Client
* @return true if this client equals the other
*/
public boolean equals(Client other)
{
if(name.equals(other.name) && phone.equals(other.phone)
&& computer.equals(other.computer) && premium == (other.premium))
{
return true;
}
else
{
return false;
}
}
}
此类通过读取文件中的请求，将其分配给代理，并将其写入与日期一起生成的报告来处理故障单。每种专业都有值班代理（Mac，Windows PC或任何系统）。
TicketSupportSystem类：
/**
* TechSupportSystem.java
*
* This class is part of Programming
* Assignment 6 - Tech Support System
* for CS1440 Summer 2013.
*
* @author Brandon C. Eason
* @author
* @version
*/
import java.util.Scanner;
import java.io.PrintWriter;
import java.io.FileWriter;
import java.io.File;
import java.io.IOException;
/**
* This class runs a tech support system
* which reads in tickets entered by clients,
* assigns them to an agent to be resolved,
* and writes them to a report.
*/
public class TechSupportSystem
{
//for keyboard input
private Scanner keyboard;
//for file input
private Scanner input;
//for writing to a file
private PrintWriter output;
//for appending to a file
private FileWriter append;
//for opening files
private File inputFile;
//today's date
private String date;
//first agent
private Agent agentOne;
//second agent
private Agent agentTwo;
//third agent
private Agent agentThree;
//the number of tickets assigned
private int numTickets;
/**
* Constructor for TechSupportSystem.
*
* @throws IOException - file not found
*/
public TechSupportSystem() throws IOException
{
System.out.println("------------------------------\n");
System.out.println("Welcome to Ticket Manager Lite\n");
System.out.println("------------------------------\n");
keyboard = new Scanner(System.in);
getDate();
getAgents();
enableWriting();
processTickets();
output.close();
System.out.println("\nTotal tickets processed: "
+ Ticket.getNumTickets());
System.out.println("\nTotal tickets assigned: " + numTickets);
}
/**
* Get today's date from the dispatcher (the user of this system).
*/
private void getDate()
{
date = "";
while (date.length() != 8)
{
System.out.print("Enter today's date(MMDDYYYY format): ");
date = keyboard.nextLine();
}
}
/**
* Verify file for opening and open it.
*
* @param fileName - the file to be opened
* @return true if valid file
*/
private boolean openFile(String fileName)
{
inputFile = new File(fileName);
return inputFile.exists();
}
/**
* Prepare file writing.
*
* @throws IOException - file not found
*/
private void enableWriting() throws IOException
{
append = new FileWriter("report.txt", true);
output = new PrintWriter(append);
output.println("--------------------------");
output.println("Ticket Report for " + date);
output.println("--------------------------\r\n");
}
/**
* Read in agents on duty.
*
* @throws IOException - file not found
*/
private void getAgents() throws IOException
{
String fileName;
do
{
System.out.print("Enter the name of the agent duty file: ");
fileName = keyboard.nextLine();
} while (!openFile(fileName));
input = new Scanner(inputFile);
agentOne = readAgent();
agentTwo = readAgent();
agentThree = readAgent();
input.close();
}
/**
* Read a single agent.
*
* @return the agent that was read
*/
private Agent readAgent()
{
String name = input.nextLine();
String id = input.nextLine();
String specialty = input.nextLine();
int time = input.nextInt();
input.nextLine();
return new Agent(name, id, specialty, time);
}
/**
* Read in the day's tickets from a file, two
* at a time, check for duplicates, assign the
* tickets to an agent, and write them to a report.
*
* @throws IOException - file not found
*/
private void processTickets() throws IOException
{
String fileName;
Ticket currentTicket;
Ticket lastTicket = null;
do
{
System.out.print("Enter the name of the ticket file: ");
fileName = keyboard.nextLine();
} while (!openFile(fileName));
System.out.println();
input = new Scanner(inputFile);
while (input.hasNext())
{
currentTicket = readTicket();
if (lastTicket == null || !currentTicket.equals(lastTicket))
{
assign(currentTicket);
output.println(currentTicket + "\r\n");
}
lastTicket = currentTicket;
}
input.close();
}
/**
* Read in a single ticket.
*
* @return the ticket that was read in
*/
private Ticket readTicket()
{
Client requester;
String description;
int minutes;
requester = readClient();
description = input.nextLine();
minutes = input.nextInt();
input.nextLine();
return new Ticket(date, description, minutes, requester);
}
/**
* Read in a single client.
*
* @return the client that was read in
*/
private Client readClient()
{
String name;
String phone;
String computer;
String premium;
boolean hasPremium = false;
name = input.nextLine();
phone = input.nextLine();
computer = input.nextLine();
premium = input.nextLine();
if (premium.equals("Premium"))
{
hasPremium = true;
}
if (computer.length() == 0)
{
return new Client(name, phone, hasPremium);
}
else
{
return new Client(name, phone, computer, hasPremium);
}
}
/**
* Assign a ticket to an agent.
*
* @param ticket - the ticket to be assigned
*/
private void assign(Ticket ticket)
{
Client requester = ticket.getClient();
String computer = requester.getComputer();
Agent solver;
if (agentOne.getSpecialty().equals(computer))
{
solver = agentOne;
}
else if (agentTwo.getSpecialty().equals(computer))
{
solver = agentTwo;
}
else
{
solver = agentThree;
}
ticket.setAgent(solver);
System.out.println("Ticket assigned to " + solver.getName() + ".");
numTickets++;
}
/**
* Starts the tech support system.
*
* @param args - not used
* @throws IOException - file not found
*/
public static void main(String[] args) throws IOException
{
new TechSupportSystem();
}
}
一切都编译正确，但是当我运行它时，在我告诉它文件并且它读取它们之后它有一个错误。它给出的错误是：
------------------------------
Welcome to Ticket Manager Lite
------------------------------
Enter today's date(MMDDYYYY format): 12121221
Enter the name of the agent duty file: agents.txt
Enter the name of the ticket file: tickets.txt
Ticket assigned to Dee.
Exception in thread "main" java.lang.NullPointerException
at Ticket.prediction(Ticket.java:153)
at Ticket.toString(Ticket.java:210)
at java.lang.String.valueOf(String.java:2979)
at java.lang.StringBuilder.append(StringBuilder.java:131)
at TechSupportSystem.processTickets(TechSupportSystem.java:178)
at TechSupportSystem.<init>(TechSupportSystem.java:62)
at TechSupportSystem.main(TechSupportSystem.java:275)
Press any key to continue . . .
所以我知道它与TechSupportSystem类中分配给lastTicket的null值有关，而且在预测中有些偏差。我只是不知道要改变什么，这将使它适用于整个processTickets和预测方法。我一直在盯着这段代码几个小时，只是在实际问题上保持大脑放屁。至少有人能指出我正确的方向吗？
感谢你在这篇长篇文章上的时间。
** ***编辑 我修复了nullexception错误。当我运行它时，一切正常。它向report.txt报告了正确的信息，但是搞乱的是它没有分配解算器。每个票证的解算器都为空。 我认为我的
有问题 /**
* Assign this ticket to an agent. The method makes a copy of the
* Agent parameter and sets the solver field to that copy.
*
* @param solver - the agent this ticket is assigned to
*/
public void setAgent(Agent solver)
{
String name = solver.getName();
String id = solver.getID();
String specialty = solver.getSpecialty();
int time = solver.getTime();
solver = new Agent(name, id, specialty, time);
}
无法弄清楚是什么。
答案 0 :(得分：0)
您很可能在没有解算器的情况下尝试打印故障单。即解算器为null
public String prediction() {
if(solver == null) return "no solver";
BTW如果您使用调试器，您应该能够在几分钟内看到问题所在。我建议你学习如何使用它，因为它可以节省你几个小时的挫折感。
最简单的解决方法是捕获异常，直到您可以修复它。
String predict;
try {
predict = prediction();
} catch (Exception e) {
predict = e.toString();
}
data += "\r\n" + predict;