Assignment
Part 1: Command Oriented Personal Information Manager
This assignment involves the creation of simple Personal Information Management system that can deal with 4 kinds of items: todo items, notes, appointments and contacts. Each of these kinds of items is described in more detail below. The assignment requires that you create a class for each item type, and that each class extends an abstract base class provided for you. In addition to creating the four classes, you need to create a manager class that supports some simple text-based commands for creating and managing items.
Each of your 4 item type classes will be derived from the following abstract class:
public abstract class PIMEntity {
String Priority; // every kind of item has a priority
// default constructor sets priority to "normal"
PIMEntity() {
Priority = "normal";
}
// priority can be established via this constructor.
PIMEntity(String priority) {
Priority = priority;
}
// accessor method for getting the priority string
public String getPriority() {
return Priority;
}
// method that changes the priority string
public void setPriority(String p) {
Priority = p;
}
// Each PIMEntity needs to be able to set all state information
// (fields) from a single text string.
abstract public void fromString(String s);
// This is actually already defined by the super class
// Object, but redefined here as abstract to make sure
// that derived classes actually implement it
abstract public String toString();
}
Todo items must be PIMEntites defined in a class namedPIMTodo. Each todo item must have a priority (a string), a date and a string that contains the actual text of the todo item.
Note items must be PIMEntites defined in a class namedPIMNote. Each note item must have a priority (a string), and a string that contains the actual text of the note.
Appointment items must be PIMEntites defined in a class namedPIMAppointment. Each appointment must have a priority (a string), a date and a description (a string).
Contact items must be PIMEntites defined in a class namedPIMContact. Each contact item must have a priority (a string), and strings for each of the following: first name, last name, email address.
There is one additional requirement on the implementation of the 4 item classes listed above, the 2 classes that involve a date must share aninterfacethat you define. You must formally create this interface and have both PIMAppointment and PIMTodo implement this interface.
You must also create a class namedPIMManagerthat includes amainand provides some way of creating and managing items (from the terminal). You must support the following commands (functionality):
List:print a list of all PIM items
Create:add a new item
Save:save the entire list of items (HW2: simple version, just print out; complex version, to a file, should be finished after I/O topic, to database, can (optional) be finished after JDBC topic, to a remote server, can (optional) be after Networking topic. )
Load:read a list of items from a file
When creating a new item it is expected that the user must response to a sequence of prompts to enter the appropriate information (and even to indicate what kind of item is being created). Do this any way you want, just make sure that your system provides enough information (instructions) so that we can use your systems!
There is no required format for the user interface, anything that allows users to create, list, save and load is fine. Here is what it might look like (user input shown in red):
java PIMManager
Welcome to PIM.
---Enter a command (suported commands are List Create Save Load Quit)---
List
There are 0 items.
---Enter a command (suported commands are List Create Save Load Quit)---CreateEnter an item type ( todo, note, contact or appointment )
todo
Enter date for todo item:
03/25/2013
Enter todo text:Submit java homework.
Enter todo priority:
urgent
---Enter a command (suported commands are List Create Save Load Quit)---
List
There are 1 items.
Item 1: TODO urgent 03/25/2013 Submit Java homework.
---Enter a command (suported commands are List Create Save Load Quit)---
Save
Items have been saved.
---Enter a command (suported commands are List Create Save Load Quit)---
Quit
Note that there is not a required Delete command. Feel free to use any data structure you want to hold a list of items, you are allowed to use a simple array with size 100 (you are not required to support lists of more than 100 items). Handling array bound exception is required.
ReimpletementPIMEntityasinterface, add change the rest of all code to use it.
mycode:
import java.util.Scanner;
import java.io.*;
interface Date{
void setDate(String d);
}
class PIMTodo extends PIMEntity implements Date{
String date,todoText;
public PIMTodo(){
}
public void setDate(String d){
date=d;
}
void setTodoText(String todo){
todoText=todo;
}
public void fromString(String s){
}
public String toString(){
return ("Item "+PIMManager.itemno+": TODO "+Priority+" "+date+" "+todoText+".");
}
}
class PIMNote extends PIMEntity{
String noteText;
void setNoteText(String n){
noteText=n;
}
@Override
public void fromString(String s) {
// TODO Auto-generated method stub
}
@Override
public String toString() {
// TODO Auto-generated method stub
return ("Item "+PIMManager.itemno+": NOTE "+Priority+" "+noteText+".");
}
}
class PIMAppointment extends PIMEntity implements Date{
String date,description;
public void setDate(String d){
date=d;
}
void setDescription(String des){
description=des;
}
@Override
public void fromString(String s) {
// TODO Auto-generated method stub
}
@Override
public String toString() {
// TODO Auto-generated method stub
return ("Item "+PIMManager.itemno+": APPOINTMENT "+Priority+" "+date+" "+description+".");
}
}
class PIMContact extends PIMEntity{
String firstname,lastname,email;
void setFirstname(String f){
firstname = f;
}
void setLastname(String l){
lastname = l;
}
void setEmail(String e){
email = e;
}
@Override
public void fromString(String s) {
// TODO Auto-generated method stub
}
@Override
public String toString() {
// TODO Auto-generated method stub
return ("Item "+PIMManager.itemno+": CONTACT "+Priority+" "+firstname+" "+lastname+" "+email+".");
}
}
public class PIMManager {
static int itemno=0;
static String[] List=new String[100];
public static void main(String[] args) throws IOException {
// TODO Auto-generated method stub
System.out.println("Welcome to PIM.");
Scanner in = new Scanner(System.in);
OUT:
while(true){
System.out.println("---Enter a command (supported commands are List Create Save Load Quit)---");
String input = in.next();
switch(input){
case "List":
System.out.println("There are "+itemno+" items.");
for(int i=1;i<=itemno;i++){
if(itemno==0) break;
System.out.println(List[i]);
}
break;
case "Create":
System.out.println("Enter an item type(todo,note,contact,appointment)");
input=in.next();
switch(input){
case "todo":
PIMTodo todo=new PIMTodo();
System.out.println("Enter date for todo item:");
BufferedReader buff=new BufferedReader(new InputStreamReader(System.in));
input=buff.readLine();
todo.setDate(input);
System.out.println("Enter todo text:");
BufferedReader buff1=new BufferedReader(new InputStreamReader(System.in));
input=buff1.readLine();
todo.setTodoText(input);
System.out.println("Enter todo priority:");
BufferedReader buff2=new BufferedReader(new InputStreamReader(System.in));
input=buff2.readLine();
todo.setPriority(input);
//start with 1(zero is not used)
itemno++;
String r=todo.toString();
List[itemno]=r;
break;
case "note":
PIMNote note=new PIMNote();
System.out.println("Enter note text:");
BufferedReader buff3=new BufferedReader(new InputStreamReader(System.in));
input=buff3.readLine();
note.setNoteText(input);
System.out.println("Enter note priority:");
input=in.next();
note.setPriority(input);
itemno++;
String r1=note.toString();
List[itemno]=r1;
break;
case "contact":
PIMContact contact=new PIMContact();
System.out.println("Enter firstname for contact item:");
BufferedReader buff4=new BufferedReader(new InputStreamReader(System.in));
input=buff4.readLine();
contact.setFirstname(input);
System.out.println("Enter lastname for contact item:");
BufferedReader buff5=new BufferedReader(new InputStreamReader(System.in));
input=buff5.readLine();
contact.setLastname(input);
System.out.println("Enter email for contact item:");
BufferedReader buff6=new BufferedReader(new InputStreamReader(System.in));
input=buff6.readLine();
contact.setEmail(input);
System.out.println("Enter contact priority:");
input=in.next();
contact.setPriority(input);
itemno++;
String r2=contact.toString();
List[itemno]=r2;
break;
case "appointment":
PIMAppointment appointment=new PIMAppointment();
System.out.println("Enter date for appointment item:");
BufferedReader buff7=new BufferedReader(new InputStreamReader(System.in));
input=buff7.readLine();
appointment.setDate(input);
System.out.println("Enter appointment description:");
BufferedReader buff8=new BufferedReader(new InputStreamReader(System.in));
input=buff8.readLine();
appointment.setDescription(input);
System.out.println("Enter appointment priority:");
input=in.next();
appointment.setPriority(input);
itemno++;
String r3=appointment.toString();
List[itemno]=r3;
break;
default:
System.out.println("the item type is not exist");
break;
}
break;
case "Save":
System.out.println("Item have been saved.");
break;
case "Quit":
in.close();
break OUT;
default:
System.out.println("the command is not exist");
break;
}
}
}
}
代码虽多，但是模式是一样的，都是从继承题目给定class PIMEntity。
使用了一个class Scanner：
Scanner in = new Scanner(System.in);
从键盘输入放到Scanner里，通过in.next()来获得键入的字符，但是如果键入的参数列表用空格隔开，它会认为是多个参数。所以如果想键入的单个参数可以用空格隔开的话，可以用：
BufferedReader buff=new BufferedReader(new InputStreamReader(System.in));
input=buff.readLine();
但它的缺点是每次使用的时候都要重新new一下，就是要创建新对象，而且每次都要不一样。就是你想输入多少个，你就创建多少个对象缓冲区。
Assignment
Part 2: Class Substring
Create a class namedSubstringthat will expect the first command line argument to be a string, and the second two command line arguments to be integers, the first will be used as an index and the second as a length. The output should be the subtring of string starting at the index and of the specified length. Examples:
> java Substring Jello 1 3
ell
> java Substring "Hello World" 0 5
Hello
> java Substring OneTwoThree 5 1
o
Notes:As you can see from the examples, an index of 0 refers to the first character in the string. To figure out how to extract a substring from a String, check out the API documentation for the class String which can be found injava.lang
my code:
public class Substring {
Substring(char[] c,int start,int length){
String s=new String();
for(int i=start;i<start+length;i++){
s=s+c[i];
}
System.out.print(s);
}
static char[] c;
static int i=0;
static int start,length;
@SuppressWarnings("unused")
public static void main(String[] args) {
// TODO Auto-generated method stub
for(String s:args){
if(i==0){
c=s.toCharArray();
}else if(i==1){
start=Integer.parseInt(s);
}else if (i==2){
length=Integer.parseInt(s);
}
i++;
}
Substring sub=new Substring(c,start,length);
}
}
another：
public class Substring{
public static void main(String[] args){
int i=Integer.parseInt(args[1]);
int j=Integer.parseInt(args[2]);
System.out.print(args[0].substring(i,i+j));
}
}
很简单的一道题，第一个实现用了toCharArray()这个函数，第二个实现用了substring()这个函数。
Assignment
Part 3: Calendar generating program
Write a java program named cal (the main() should be in a class named "cal") that will print out to standard output the calendar for any month. Your program should look at the command line arguments for a numeric month and year, and print the calendar for that month in the format displayed below. If there are no command line arguments, or if the command line arguments are not a valid month and year, your program must print the calendar for the current month. This program is a java version of the Unix "cal" command. Sample usage of your program is shown below:
> java cal
March 2013
Su Mo Tu We Th Fr Sa
1 2
3 4 5 6 7 8 9
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
31
> java cal 4 2025
April 2025
Su Mo Tu We Th Fr Sa
1 2 3 4 5
6 7 8 9 10 11 12
13 14 15 16 17 18 19
20 21 22 23 24 25 26
27 28 29 30
As the above examples show, the program should print out the month and year, followed by the days of the week (using the same abbreviation as shown above) and the dates in the month. Your program must produce a tabular output exactly like the above examples, the only difference should be the exact position of the dates (which depend on the specific month asked for). It is required that the columns of the calendar line up just like the above examples!
Notes:
You probably want to use a java.util.Calendar object!
my code:
import java.util.*;
public class cal {
static int daysInMonth( Calendar c) {
return(c.getActualMaximum(Calendar.DAY_OF_MONTH));
}
static String dayName( Calendar c) {
// Need to subtract 1, since the first DAY_OF_WEEK is 1 !
return(DAYS[c.get(Calendar.DAY_OF_WEEK)-1]);
}
static String monthName(Calendar c) {
return(MONTHS[c.get(Calendar.MONTH)]);
}
cal(int month,int year){
Calendar c = Calendar.getInstance();
//clear is important
c.clear();
c.set(Calendar.YEAR,year);
c.set(Calendar.MONTH,month);
int day=daysInMonth(c);
// c.set(Calendar.DATE,1);
// c.roll(Calendar.DATE,-1);
// int day=c.get(Calendar.DATE);
int b=c.get(Calendar.DAY_OF_WEEK);
String mn=monthName(c);
System.out.println(mn+" "+year);
System.out.println("Su Mo Tu We Th Fr Sa");
for(int i=1;i<b;i++){
System.out.print(" ");
}
for(int i=1;i<=day;i++){
if (i<10){
System.out.print(" "+i+" ");
}else{
System.out.print(i+" ");
}
if(b==7){
System.out.println();
b=1;
}else{
b++;
}
}
}
static final String[] DAYS ={ "Sunday",
"Monday",
"Tuesday",
"Wednesday",
"Thursday",
"Friday",
"Saturday" };
static final String[] MONTHS = { "January",
"February",
"March",
"April",
"May",
"June",
"July",
"August",
"September",
"October",
"November",
"December"};
static int i=0;
@SuppressWarnings("unused")
public static void main(String[] args) {
// TODO Auto-generated method stub
Calendar c=Calendar.getInstance();
for (String s:args ) {
i++;
}
if(i==0){
int month=c.get(Calendar.MONTH);
int year=c.get(Calendar.YEAR);
cal calendar=new cal(month,year);
}else{
int month = Integer.parseInt(args[0])-1;
int year = Integer.parseInt(args[1]);
cal calendar=new cal(month,year);
}
}
}
这个题目就是让我们了解一下class Calendar。
Calendar c = Calendar.getInstance();
返回当前的时间
经常用的set(),get()方法。
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