辅导CS1027B 辅导留学生Java语言

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CS1027B

ASSIGNMENT 1 Computer Science Fundamentals II

This assignment is due on Friday, July 3, 2020 by 11:55pm. See the bottom for submission

details.

Purpose

To gain experience with

 Creating classes with simple methods

 Inheritance and sub-classes

 Reading from a text file

 Algorithm design

Introduction

In honour of Canada Day (July 1), this first assignment has a theme of Canadian geography.

You are constructing a program that displays a map of Canada and some of the notable cities

across the country. There is a panel in the upper-left corner overlaid on the map, and this panel

contains information about the country. By default, it displays statistics about the various cities'

populations. This panel changes when a selection is made – which is done by right-clicking

down and dragging the mouse and then letting go to complete the selection – to display the list

of cities located within the bounds of that rectangular selection.

Notes: City locations are approximate and indicated by the bottom point of the marker icons.

Populations are approximate, rounded, and may not be up to date.

CS1027B

ASSIGNMENT 1 Computer Science Fundamentals II

Figure 1. A screenshot of the finished product, the map of Canada displayed with various city

markers indicating capitals and other popular cities. A region of the map has been selected,

shown as a blue translucent rectangle, and the panel in the upper-left corner displays the cities

contained in the selected region.

Provided files

The following is a list of files provided to you for this assignment. Please do not alter these files

in any way.

CS1027B

ASSIGNMENT 1 Computer Science Fundamentals II

 MyFileReader.java – helps with reading a text file

 Map.java – provides the visual GUI for the program

 TestClasses.java – provides several tests to check that your code is working correctly

 cities.txt – contains the list of Canadian cities and their info to be read into the program

 canada.jpg – map of Canada

 marker_city.png – marker icon for a non-capital city

 marker_prov.png – marker icon for a provincial capital city

 marker_nat.png – marker icon for the national capital city

Classes to implement

For this assignment, you must implement 4 Java classes: City, ProvCapital, NatCapital, and

Program. Follow the guidelines for each one below.

In all of these classes, you can implement more private (helper) methods, if you want to, but you

may not implement more public methods. You may not add instance variables other than the

ones specified below. Penalties will be applied if you implement additional instance variables.

City.java

This class represents one city in the program. It contains information about the city and is used

by the provided Map class to display the city's marker. Note that you will have to import

javax.swing.ImageIcon in this City class and its sub-classes in order to use the marker icons.

The class must have the following private variables:

 name (String)

 population (int)

 x (int)

 y (int)

 marker (ImageIcon)

The class must have the following public methods:

 City (constructor) – takes in parameters for name, population, x, and y and assigns their

values into the corresponding instance variables. The marker instance variable is

initialized as a new ImageIcon object with the "marker_city.png" image file.

 getName – returns the city's name

 getPopulation – returns the population

 getX – returns the x coordinate

CS1027B

ASSIGNMENT 1 Computer Science Fundamentals II

 getY – returns the y coordinate

 getMarker – returns the marker icon

 setName – takes in a new name parameter and assigns it to the corresponding variable

 setPopulation – takes in a new population parameter and assigns it to the corresponding

variable

 setMarker – takes in a new marker parameter and assigns it to the corresponding

variable

 equals – takes in a parameter of an "other" City object and checks if "this" and "other"

are equal, by checking if both the x distance and y distance are less than 5 pixels. For

example if CityA is located at (100, 200) and CityB is located at (102, 196), they are

considered equal because in both dimensions they are within 5 pixels of one another.

 toString – returns the city's name to be printed out when the city object is printed

ProvCapital.java

This class represents a city that is a capital of a province or territory in Canada. Since it is a

specific category of some cities, this class must be created as a sub-class of City.

In addition to the inherited variables from City, this class must have one private instance

variable:

 province (String)

The class must have the following public methods:

 ProvCapital (constructor) – takes in parameters for name, population, x, y, and province.

The first four of which must be sent to the super-class constructor first. The province

parameter value must then be assigned to the corresponding instance variable. The

marker instance variable is initialized as a new ImageIcon object with the

"marker_prov.png" image file. (Hint: how can you set this marker icon even though it's

private and declared in a different class?)

 toString – return the city's name followed by a space and then the province in which this

city is the capital, surrounded by parentheses (i.e. Toronto (Ontario)).

NatCapital.java

This class represents the city that is the capital of Canada (Ottawa). Since it is a specific

category of a city, this class must be created as a sub-class of City.

This class does not require any new instance variables, it only needs those that are inherited

from City.

CS1027B

ASSIGNMENT 1 Computer Science Fundamentals II

The class must have the following public methods:

 NatCapital (constructor) – takes in parameters for name, population, x, and y, which

must all be sent to the super-class constructor first. The province parameter value must

then be assigned to the corresponding instance variable. The marker instance variable is

initialized as a new ImageIcon object with the "marker_nat.png" image file.

 toString – return the city's name followed by a space and then "Canada's capital"

surrounded by parentheses (i.e. Ottawa (Canada's capital)). Even though there is only

one capital, don't hard-code the first part of this string (Ottawa) but rather retrieve the

variable from the object.

Program.java

This class, as its name suggests, will be the main heart of the program. It will be the entry point

of the program, read in the file of cities and create objects for each of them, contain the array of

those cities, as well as perform tasks that interact with the GUI.

This class must have only one variable:

 cityArray (City array) – it must be private and static

The class must have the following methods:

 Program (public constructor) – take in a boolean parameter "showMap" which will

indicate whether we want to run the program with the visual component or not. Initialize

the cityArray with 5 slots to begin. Create a MyFileReader object to open and read the

cities.txt file. The first line is header info and must be read in but can be immediately

discarded. After that, the file follows a specific format in which each line contains one

piece of information in the following order: city name, population, x, y, type, [prov]. The

type will either be "nat_cap" (national capital), "prov_cap" (provincial capital), or "city" for

a non-capital city. The [prov] line is only provided for provincial capital cities. All other

cities will not have the province mentioned. As you read in each set of the city's

properties, create a City object containing the info and add it to cityArray. When needed,

call expandCapacity to create more space. After all the cities have been read and

created, check the value of the parameter, showMap. If it is true, create a Map object

and invoke its addCity() method with each of the city objects in cityArray to add their

markers to the map. Call the map's defaultText method. If showMap is false, do nothing.

 getCityList (public) – return the global array of cities

 expandCapacity (private) – create a new array that has 5 more spots than cityArray has,

and then transfer the contents from cityArray to this new array and point the cityArray

 findCitiesInRect (public static) – take in four int parameters: sx, sy, ex, and ey which

represent the (x, y) coordinate of one corner of a selection and the (x, y) coordinate of

the diagonally opposite corner of the selection. Find all the cities that are located within

CS1027B

ASSIGNMENT 1 Computer Science Fundamentals II

the bounds of the rectangle defined by (sx,sy) and (ex,ey) and add them into a City array

in the same order they are stored in cityArray but without gaps in the array. They must

all be in consecutive array slots. You may not use any different data structures or

collections for this process. Note that the regions can go in any direction, i.e. sx isn't

necessarily less than ex, and same with sy and ey. You must account for all cases. Note

also that cityArray may have null slots so check for this to avoid exceptions. Return the

City array containing the cities within the selection bounds at the end of the method. The

Map class is already set up to call this method and use the results in the returned array

to be displayed in the upper-left panel. The following figures demonstrate selections in

opposite directions and the corresponding sx, sy, ex, and ey placements. In the left

figure, the selection begins at the upper left corner (sx, sy) and ends in the lower right

corner (ex, ey). In the right diagram, the selection begins in the lower right corner (sx, sy)

and ends in the upper left corner (ex, ey).

 defaultTextboxInfo (public static) – calculate the average, minimum, and maximum

populations of all capital cities (including the provincial capitals and the national capital)

and the City objects which have the minimum and maximum populations. Then do the

same thing for the non-capital cities. In total you will compute 6 values and for 4 of them

you will also need the corresponding City object. Return an Object array with each of

these results in the order shown below. The average stats must be doubles, the min and

max stats must be integers, and the remaining results must be City objects that

correspond to the min or max stats. The Map class is set up to call this method and use

the results as the default text in the upper-left panel when there is not an active selection

on the map. The results in the array must be ordered as:

array[0] = avg value (caps)

array[1] = min value (caps)

array[2] = min City (caps)

array[3] = max value (caps)

array[4] = max City (caps)

array[5] = avg value (non caps)

array[6] = min value (non caps)

array[7] = min City (non caps)

array[8] = max value (non caps)

array[9] = max City (non caps)

CS1027B

ASSIGNMENT 1 Computer Science Fundamentals II

Marking notes

Marking categories

 Functional specifications

o Does the program behave according to specifications?

o Does it produce the correct output and pass all tests?

o Are the class implemented properly?

o Are you using appropriate data structures?

 Non-functional specifications

o Are there Javadocs comments and other comments throughout the code?

o Are the variables and methods given appropriate, meaningful names?

o Is the code clean and readable with proper indenting and white-space?

o Is the code consistent regarding formatting and naming conventions?

 Penalties

o Lateness: 10% per day

o Submission error (i.e. missing files, too many files, ZIP, etc.): 5%

o "package" line at the top of a file: 5%

Remember you must do all the work on your own. Do not copy or even look at the work of

another student. All submitted code will be run through cheating-detection software.

Submission (due Friday, July 3, 2020 at 11:55pm EDT)

To submit the assignment, navigate to Week 2 (or Week 1) and click on Assignment 1. In this

assignment page, attach the files listed below to the assignment page and click Save and

Submit. Check that your submission went through on there and look for an automatic OWL

email to verify that it was processed. Incomplete or incorrect submissions will be subject to

penalties, so verify the submission before closing OWL.

Rules

 Please only submit the files specified below. Do not attach other files even if they were

part of the assignment.

 Do not ZIP or use any other form of compressed file for your files. Attach them

individually.

CS1027B

ASSIGNMENT 1 Computer Science Fundamentals II

 Submit the assignment on time. Late submissions will receive a penalty of 10% per day.

 Forgetting to hit "Submit" is not a valid excuse for submitting late.

 Submitting the files in an incorrect submission page will receive a penalty.

 You may re-submit code if your previous submission was not complete or correct,

however, re-submissions after the regular assignment deadline will receive a penalty.

Files to submit

 City.java

 ProvCapital.java

 NatCapital.java

 Program.java