Download Person Hierarchy - Stonehill College

Person Class Hierarchy
This example has most of what we have covered so far with
inheritance and also exploits polymorphism
(The constructors are not pictured in the diagram)
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public abstract class Person implements Comparable
{
protected String lastName;
protected String firstName;
public Person()
{
lastName = "";
firstName = "";
}
public Person(String last, String first)
{
lastName = last;
firstName = first;
}
public String getName()
{
return lastName+firstName;
}
public int compareTo(Object o) // from the Comparable interface
{
String name = lastName + firstName;
String name1 = ((Person)o).lastName+((Person)o).firstName;
return name.compareTo(name1);
//uses compareTo() in the String class
}
public boolean equals(Object o) // override equals(..) inherited from Object
{
String name = lastName + firstName;
String name1 = ((Person)o).lastName+((Person)o).firstName;
return name.equals(name1); //uses equals() in the String class
}
public String toString() // override toString() inheritedfrom Object
{
return lastName+", "+firstName;
}
}
2
public abstract class Employee extends Person
{
protected String department;
public Employee()
{
super(); // call the default constructor of Person
department = "";
}
public Employee(String last, String first, String department)
{
super(last, first); // call 2-argument constructor of Person
this.department = department;
}
public String toString()
{
return super.toString() + " Department: "+ department;
//calls toString() of the parent (Person)
}
}
//////////////////////////////////////////////////////////////////////////////////////////////
public abstract class Student extends Person
{
protected String major;
protected double gpa;
public Student()
{
super();// call the default constructor of Person
major = "";
gpa = 0.0;
}
public Student(String last, String first, String major, double gpa)
{
super(last, first); // call 2-argument constructor of Person
this.major = major;
this.gpa = gpa;
}
public String toString()
{
return super.toString()+ " Major: " + major+" GPA: "+gpa;
//calls toString() of the parent (Person)
}
}
3
public class UndergradStudent extends Student // NOT abstract
{
protected int year;
public final String CODE = "u"; //constant
public UndergradStudent()
{
super(); // calls default constructor of Student
year = 2014;
}
public UndergradStudent(String last, String first, String major,
double gpa, int year)
{
super(last, first, major, gpa); // calls 4-arg constructor of Student
this.year = year;
}
public String toString()
{
return super.toString()+ " Class: "+ year;
//calls toString() of the parent (Student)
}
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
public class GradStudent extends Student // NOT abstract
{
protected String advisor;
public final String CODE = "g"; //constant
public GradStudent()
{
super();// calls default constructor of Student
advisor = "";
}
public GradStudent(String last, String first, String major, double gpa,
String advisor)
{
super(last, first, major, gpa); // calls 4-arg constructor of Student
this.advisor = advisor;
}
public String toString()
{
return super.toString()+ " Advisor: ";
//calls toString() of the parent (Student)
}
}
4
public class Administration extends Employee // NOT abstract
{
protected String position;
public final String CODE = "a";
public Administration()
{
super(); // calls default constructor of Employee
position = "";
}
public Administration(String last, String first, String department, String position)
{
super(last, first, department); // calls the 3-arg constructor of Employee
this.position = position;
}
public String toString()
{
return super.toString() + " Department: "+ department+ " Position: "+ position;
//calls toString() of the parent (Employee)
}
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
public class Faculty extends Employee // NOT abstract
{
protected String rank;
public final String CODE = "f";
public Faculty()
{
super();// calls default constructor of Employee
rank = "";
}
public Faculty(String last, String first, String department, String rank)
{
super(last, first, department); // calls the 3-arg constructor of Employee
this.rank = rank;
}
public String toString()
{
return super.toString() + " Department: "+ department+ " Rank: "+ rank;
//calls toString() of the parent (Employee)
}
}
5
import java.util.*;
import java.io.*;
public class CollegeData
{
private Person[] p = null; // can hold any object in the hierachy
private int numPerson;
// number of items in p
private String code = "";
public CollegeData() throws IOException // default constructor
{
//The default constructor reads the data from the file "college.txt"
// and stores the data in the array p
// The first character of every record indicates whether the
// record is data for an Administrator, Faculty, Ungergrad or Grad Student
File f = new File("college.txt");
if (!f.exists())
{
System.out.println("File college.txt does not exist");
System.exit(0);
}
Scanner input = new Scanner(f);
p = new Person[100];
numPerson = 0;
while(input.hasNext())
{
code = input.next();
// read the first letter (code) in each person's record
if (code.equals("a")) // "a" is code for Administrator
{
// read the data and instantiate and Administration object
String last = input.next();
String first = input.next();
String department = input.next();
String position = input.next();
p[numPerson] = new Administration(last, first, department, position);
}
else if (code.equals("f")) // Faculty --"f" is code for Faculty
{
// read the data and instantiate a Faculty aobject
String last = input.next();
String first = input.next();
String department = input.next();
String rank = input.next();
p[numPerson] = new Faculty(last, first, department, rank);
}
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else if (code.equals("g")) //GradStudent
{
// read the data and instantiate a GradStudent object
String last = input.next();
String first = input.next();
String major = input.next();
double gpa = input.nextDouble();
String advisor = input.next();
p[numPerson] = new GradStudent(last, first, major,gpa, advisor);
}
else // Undergrad -- last code is "u"
{
// read the data and instantiate a UndergradStudent object
String last = input.next();
String first = input.next();
String major = input.next();
double gpa = input.nextDouble();
int year = input.nextInt();
p[numPerson] = new UndergradStudent(last, first, major, gpa, year);
}
numPerson++;
}
SelectionSort.sort(p,numPerson);
// sort the array p using the static method in SelectionSort
// sorting is based on lastName+FirstName
// since compareTo(...) uses that criterion to compare objects
}
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public String menu()
{
// Asks the user for the class of Persons to display
// returns the user's choice
String code= "";
Scanner input = new Scanner(System.in);
System.out .println("Enter one of the following codes");
System.out.println("P --> All persons at the college");
System.out.println("E --> All employees at the college");
System.out.println("S --> All students at the college");
System.out.println("A --> All administrators at the college");
System.out.println("F --> All faculty at the college");
System.out.println("G --> All grad students at the college");
System.out.println("U --> All employees at the college");
boolean validCode = false;
while( !validCode) // stay in loop until a valid code is entered
{
code = input.next();
if (!"PESAFGU".contains(code))
System.out.println("Invalid code. Re-enter P E S A F G or U:");
else
validCode = true;
}
return code;
}
public void display(String code)
{
// Accepts the code of the user and
// traverses the array printing thise records\
// that match the code entered by the uses
for(int i = 0; i < numPerson; i++)
{
if (code.equals("P") || // everyone
code.equals("E") && p[i] instanceof Employee || //Admins and Faculty
code.equals("S") && p[i] instanceof Student || //undergrads and grads
code.equals("G") && p[i] instanceof GradStudent || // just grads
code.equals("U") && p[i] instanceof UndergradStudent || // undergrads
code.equals("A") && p[i] instanceof Administration || // administrators
code.equals("E") && p[i] instanceof Faculty) // just faculty
System.out.println(p[i]);
// calls p[i].toString()
}
}
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public static void main(String[] args) throws IOException
{
Scanner input = new Scanner(System.in);
String answer = "";
CollegeData data = new CollegeData();
do
{
String choice = data.menu();
data.display(choice);
System.out.print("\n\nRun again? Enter Y or y for yes; any char for no: ");
answer = input.next();
} while( answer.equals("y") || answer.equals("Y"));
}
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
Here is a sample input file: college.txt
The first character on each line denotes they type of object or record -f --> Faculty
a --> Administration
u --> UndergradStusent
g--> GradStudent
f Simpson Homer Math Assistant-Professor
f Krabapple Edna English Professor
f Bouvier Patty Health Associate-Professor
f Beardly Jasper Spelling Instructor
f Amadopolis Ari Classics Assistant-Professor
u Simpson Bart Philosophy 2.1 2015
u Simpson Lisa Math 4.0 2017
u Simpson Maggie History 2.7 2018
u Muntz Nelson PhyEd 2.0 2015
u Bouvier Selma Physics 2.1 2014
g Flanders Ned Art 3.2 Itchy
g Simpson Maggie Cosmotology 3.2 Scratchy
g Barton Wendel Biology 3.1 Blinky
g Hermann Herman Military-Science 2.7 Krusty
g Gumble Barney Chemistry 1.7 Krusty
a Bailey Mary Academics VP
a Borton Wendell Finance Bursar
a Chalmers Gary Academics Dean
a Lovejoy Timothy Campus-Ministry Director
a Brockman Kent Student-Affairs Housing-Director
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