Question
***For beginners learning java****code simple as possible DB.TXT 8749e 1995-11-02 1-475-942-1615 Eva Destruction 1eb25 1980-02-13 1-651-260-8773 Bob Loblaw a1ed6 1982-10-10 1-732-572-2182 Penumbra Lua 6f90d 1965-11-18
***For beginners learning java****code simple as possible
DB.TXT
8749e 1995-11-02 1-475-942-1615 Eva Destruction
1eb25 1980-02-13 1-651-260-8773 Bob Loblaw
a1ed6 1982-10-10 1-732-572-2182 Penumbra Lua
6f90d 1965-11-18 1-425-215-7673 Sara Soda
2062c 1969-11-22 1-209-601-6270 Sy Borg
f734f 1973-01-19 1-213-944-8230 Jerry Hattrick
78075 1958-12-25 1-671-589-5690 Phil Anthropic
50889 1983-07-15 1-727-668-6289 Casper Bhoot
ea061 1971-03-19 1-604-380-2489 Squarebob Sponge Pants
52079 1957-08-28 1-226-515-1667 Helen Wheels
bdd10 1987-05-21 1-217-373-8703 Al Debaron
1c8ff 1973-01-08 1-443-616-3160 Jay Walker
4b7aa 1956-02-24 1-330-875-3842 Tim Buck, II
762ce 1991-04-10 1-626-403-5794 Anne Ominous
051d0 1978-11-15 1-678-869-8794 Art Rococo
4bd11 1981-05-25 1-714-786-4352 James Rivers
708a0 1967-05-17 1-223-969-3944 Pat Pending
2cc01 1967-10-10 1-670-457-5427 Sarah Bellum
86f4d 1971-09-21 1-510-479-0309 Lucinda D. Boltz
c16fc 1977-02-10 1-343-390-8956 Mickey Angels
e7c2a 1984-12-23 1-443-794-6553 C. Erol Madre
0221c 1980-05-28 1-246-584-4760 Mora Leigh Flexible
92233 1987-10-21 1-246-958-0440 Mischa Ternoff
67a1e 1959-04-07 1-417-632-7055 Les Active
cb4c2 1959-01-16 1-289-502-8337 Thomas Katz
2d886 1980-09-02 1-531-824-7428 Marge N. O'Hara
db3b5 1979-12-09 1-669-274-5143 Warren Pease
6404a 1971-03-14 1-441-966-3391 Kim Chee
5acee 1993-05-07 1-206-409-4897 Chester Peak
7a47f 1998-02-16 1-345-686-3902 James Bonn
c47be 1981-12-23 1-256-456-1013 James URL Jones
250b1 1971-11-16 1-242-234-0405 Thomas Foolery
715de 1997-10-27 1-541-983-1179 Kaye Serah
fe976 1990-02-25 1-253-986-1746 Jan Derr
53a69 1967-03-26 1-406-809-6518 Austin Tatious
145a4 1965-01-02 1-509-984-5444 Zbigniew Payne
f764e 1963-06-15 1-603-429-7578 Anne Hinga
e9ddd 1972-07-23 1-680-556-5252 Al Kaline
86e04 1997-07-12 1-620-985-0242 Champ Payne
38c9a 1960-08-25 1-332-442-0612 Tom Ollay
3c927 1955-11-01 1-204-914-8142 Erol Flintstone
c9ebd 1967-01-26 1-304-515-5362 Bea Faroni
002e0 1989-09-29 1-212-991-7893 Mary Anna Trench
50dd6 1985-12-26 1-608-262-6154 Phil O'Sophie
12d01 1966-03-12 1-717-525-9844 Dinah Might
30329 1977-04-01 1-612-308-4694 Chip Monk
45681 1963-02-11 1-503-645-1827 Al Feedersain
2b1d4 1984-04-18 1-215-408-4630 Sally Forth
ffd97 1979-02-09 1-763-704-0325 Noah Pinion
0f4ae 1978-11-14 1-242-915-1604 Sarah N. Dippity
d0c39 1955-04-08 1-226-597-3033 Al Italia
2fef7 1955-11-12 1-408-465-9176 Frank N. Stein
f923d 1963-10-29 1-281-258-7205 Yagotta B. Kidding
c333c 1970-03-04 1-500-865-5942 Catnip Evergreen
e0a08 1971-03-02 1-562-867-1518 Joe King
17d47 1961-02-01 1-613-300-5295 Karen Sympathy
d3d0c 1996-07-21 1-254-427-1723 Cassie O. Pia
d4daa 1998-12-03 1-607-883-3522 Moses Lonagin
Consider the following Person class. Its fields correspond to the fields
on each line in the db.txt file from homework 3. In db.txt, the ID is 5
hexadecimal digits. This fits in a 32-bit int. I could have used decimal
instead, but decimal would have required an extra column (and so an
extra byte per line).
The other fields are strings.
The constructor assumes the data is in the expected format. It takes, as
a string, a line from the db.txt file, and scans through the line,
picking out and saving the ID, the date of birth, the phone number, and
the person's name. Note the special handling to convert the ID from a
hexadecimal string to an int. Also note that Scanner's nextLine() method
is used for the name, but just next() for the other fields. This is
because the name could be any number of tokens in length. We just grab
all that is left on the line as the name.
toString() overrides toString() from the Object class. Notice how the ID
is converted back to hexadecimal for display.
class Person {
private final int id; // 5 hex digits fits in one 4B int, or a
// 10B UTF-16 String. Pick the smaller.
private final String dob; // date of birth
private final String phone;
private final String name;
static final int RADIX = 16; // hexadecimal (base 16)
public Person(final String line) {
// Could throw if there are too few tokens or if the first token
// isn't a hex value. Ignores anything past the fourth token.
final Scanner s = new Scanner(line);
id = s.nextInt(RADIX);
dob = s.next();
phone = s.next();
name = s.nextLine();
} // constructor
public int id() { // accessor/getter
return id;
} // id()
@Override
public String toString() {
return
Integer.toHexString(id) + " "
+ dob + " "
+ phone + " "
+ name;
} // toString()
} // class Person
Make a Java program that creates a Person object for each line in
db.txt. These Person objects must be stored in an ArrayList
*not* modify Person.
Your program will consist of Person and new class called People. People
must have:
(1) A private final field of type ArrayList
java.util.
(2) A constructor that receives the name of the input file, reads the
file, and places each line of the file in the ArrayList
(2a) Here's how to open the input file:
final Scanner in = new Scanner(new File(filename));
where filename is the name of the input file. File is in
java.io.
(2b) The constructor will loop while in.hasNextLine() returns true.
(2c) A person can be added to the ArrayList
db.add(new Person(in.nextLine());
Here db is the ArrayList
name.
(2d) Be sure to close the input file.
(2e) The constructor must be declared to throw
FileNotFoundException. Do *not* catch the exception in the
constructor, since that may result in a poorly-initialized People
instance. FileNotFoundException may be imported from java.io.
(3) A public function get() which receives a Person ID as an int,
searches the ArrayList for the matching Person, and returns the matching
Person. If no match is found, return null.
(4) A toString() method that overrides toString() in Object. This must
be tagged @Override. This method takes no arguments, and returns a
String. The returned String will be all the Person objects concatenated,
one per line (separated by newline characters).
(5) A main() function that creates a new People instance, passing it
"db.txt" as an argument. main() then prompts the user for an ID number,
reads the ID number, and displays the matching Person. If no matching
Person is found, display a message indicating that the ID is unknown.
Feel free to use the following code to prompt for and read an ID:
private static Scanner in = null;
private static String promptForInput(final String prompt) {
System.out.print(prompt);
if (in == null) // only need one Scanner
in = new Scanner(System.in);
final String result = in.nextLine();
if (result.equals("q"))
return null;
else return result;
} // promptForInput()
Note that get() and toString() perform *NO* I/O.
For full credit, do NOT index into the ArrayList. Use ForEach loops
(section 7.2.7 of the 10th edition of the text).
What to submit:
(1) Your Java source code (this is the file ending in .java).
(2) A screen shot showing two runs of your program, one where the
requested ID is found, and one where the ID is not found.
At the top of the file must be a comment identifying the programmer or
programmers.
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Relational Database Design A Practical Approach
Authors: Marilyn Campbell
1st Edition
1587193175, 978-1587193170
