Inheritance. 

The text file. Working class dogs not added yet

Butch#2#false
April#1#true
Morgan#4#false
Ratty#9#false
Tut#2#true
===========================================================
The UI class that will call the methods in the manager class

/*
 * Super class: Dogs. Subclass: Working dogs
 * Read in from a text file
 */
package inheritance;

public class DogsUI {

    public static void main(String[] args) {
        DogManager dm = new DogManager();
        String text = dm.displayAll();
        System.out.println("Hello Dogs");
        System.out.println(text);
    }
}
===============================================================
The Manager class where we will place all our methods.
The constructor method will read in the text file and 
instantiate an array of dog objects.

/*
 * Dog Manager with methods to create object arrays
 */
package inheritance;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
import java.util.logging.Level;
import java.util.logging.Logger;

public class DogManager {
    // global variables including arrays
    private Dogs[] dogArray = new Dogs[20];
    private int size = 0;
    
    DogManager() {
        try {
            Scanner scFile = new Scanner(new File("dogs.txt"));
            
            while(scFile.hasNext()) {
                String line = scFile.nextLine();
                Scanner scLine = new Scanner(line).useDelimiter("#");
                String name = scLine.next();
                String ageSt = scLine.next();
                int age = Integer.parseInt(ageSt);
                String pedigreeSt = scLine.next();
                boolean pedigree = Boolean.parseBoolean(pedigreeSt);
                
                dogArray[size] = new Dogs (name, age, pedigree);
                size = size + 1;
                
            } // end while
            System.out.println("File Found");
        } catch (FileNotFoundException ex) {
            Logger.getLogger(DogManager.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
    
    public String displayAll() {
        String s = "";
        for(int i = 0; i < size; i++) {
            s = s + dogArray[i] + "\n";
        } // end for
        return s;
    }
}
==============================================================================
The Dog class - the super class. The dog class constructor must match the
working dog constructor. 

/*
 * Super class: Dogs. Subclass: Working dogs
 */
package inheritance;

public class Dogs {
    String name = null;
    int age = 0;
    boolean pedigree = false;
    
    Dogs(String n, int a, boolean p) {
        name = n;
        age = a;
        pedigree = p; 
    }
    
public String toString() {
    
    return name + "\t" + age + "\t" + pedigree;
}
}
===============================================================================
/*
 * Extends the dog class
 */
package inheritance;

public class WorkingDog extends Dogs{
    // Working dog has an additional field
    String trainer = "Nil";
    
    // Sub-class constructor uses the super-class constructor, just adding the
    // extra field
	
    WorkingDog(String n, int a, boolean p, String t) {
        super(n,a,p);
        trainer = t;
    } // end constructor

public String toString() {
    // returns Dog toString with the extra field
    return super.toString() + "\t" + trainer;
}
}
================================================================================

OUTPUT

run:
File Found
Hello Dogs
Butch	2	false
April	1	true
Morgan	4	false
Ratty	9	false
Tut		2	true
=================================================================================