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Chicken factory

Java Core, Level 4, Lesson 6

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Stuck with run time errors: non-static variable this cannot be referenced from a static context. Nee some help!

Write a factory (HenFactory) for making chickens (Hen):

1. Write a Hen class.
1.1. Make it abstract.
1.2. Add an int getMonthlyEggCount() method to the abstract class.
1.3. Add a String getDescription() method to the class. It should return "I am a chicken."
2. Create an NorthAmericanHen class that inherits Hen.
3. Create an EuropeanHen class that inherits Hen.
4. Create an AsianHen class that inherits Hen.
5. Create an AfricanHen class that inherits Hen.
6. In each of these four classes, write your own implementation of the getMonthlyEggCount method.
The method should return the number of eggs per month produced by that type of chicken.
7. In each of these four classes, write your own implementation of the getDescription method.

The method must return a string as follows:
<parent class>.getDescription() + " I come from <continent>. I lay <n> eggs a month."
where <continent> is the name of the continent
and <n> is the number of eggs per month.

8. In the HenFactory class, implement the getHen method. It should return a chicken breed corresponding to the continent that the chicken came from.
9. All the classes you create must be in separate files.

Requirements:

The Hen class must be abstract.
The Hen class must have an abstract int getMonthlyEggCount() method.
The Hen class must implement a String getDescription() method, which returns "I am a chicken."
The NorthAmericanHen, EuropeanHen, AsianHen, and AfricanHen classes must inherit the Hen class and be located in separate files.
The NorthAmericanHen, EuropeanHen, AsianHen, and AfricanHen classes must implement the getMonthlyEggCount method, which should return the number of eggs per month laid by the corresponding type of chicken.
The NorthAmericanHen, EuropeanHen, AsianHen, and AfricanHen must override the parent class's getDescription method so that the returned string looks like this: <parent class>.getDescription() + " I come from <continent>. I lay <n> eggs a month." where <continent> is the name of the continent, and <n> is the number of eggs per month.
The getHen method must be implemented in the HenFactory class and must return the chicken type that corresponds to the passed continent.

package com.codegym.task.task14.task1408; /* Chicken factory */ public class Solution { public static void main(String[] args) { Hen hen = HenFactory.getHen(Continent.AFRICA); System.out.println(hen.getMonthlyEggCount()); System.out.println(hen.getDescription()); } static class HenFactory { static Hen getHen(String continent) { Hen hen = null; //write your code here if (continent.equalsIgnoreCase("northamerica")) { hen = new NorthAmericanHen(); } else if (continent.equalsIgnoreCase("europe")) { hen = new EuropeanHen(); } else if (continent.equalsIgnoreCase("asia")) { hen = new AsianHen(); } else if (continent.equalsIgnoreCase("africa")) { hen = new AfricanHen(); } return hen; } } public class NorthAmericanHen extends Hen{ int eggCount = 25; @Override public int getMonthlyEggCount() {return eggCount;} @Override public String getDescription() { String result = super.getDescription() + " I come from NorthAmerica. I lay " + getMonthlyEggCount() + " eggs a month."; return result; } } public class EuropeanHen extends Hen{ int eggCount = 25; @Override public int getMonthlyEggCount() {return eggCount;} @Override public String getDescription() { String result = super.getDescription() + " I come from Europe. I lay " + getMonthlyEggCount() + " eggs a month."; return result; } } class AsianHen extends Hen{ int eggCount = 25; @Override public int getMonthlyEggCount() {return eggCount;} @Override public String getDescription() { String result = super.getDescription() + " I come from Asia. I lay " + getMonthlyEggCount() + " eggs a month."; return result; } } class AfricanHen extends Hen{ int eggCount = 25; @Override public int getMonthlyEggCount() {return eggCount;} @Override public String getDescription() { String result = super.getDescription() + " I come from Africa. I lay " + getMonthlyEggCount() + " eggs a month."; return result; } } }

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// Java Poser

Level 18 , Cincinnati, United States

12 April 2019, 16:56

Also implement the Continent class into all four of your hen classes so you can concatenate the variables into your output more accurately

// Java Poser

Level 18 , Cincinnati, United States

12 April 2019, 16:55

implement the Continent Interface in all of your classes which will allow you to use the variables in Continent. So you can change this:

if (continent.equalsIgnoreCase("northamerica")) {
                 hen = new NorthAmericanHen();
             } else if (continent.equalsIgnoreCase("europe")) {
                 hen = new EuropeanHen();
             } else if (continent.equalsIgnoreCase("asia")) {
                 hen = new AsianHen();
             } else if (continent.equalsIgnoreCase("africa")) {
                 hen = new AfricanHen();
             }

Change it to this:

static Hen getHen(String continent) {
            Hen hen = null;
            if (continent.equals(EUROPE)) {
                hen = new EuropeanHen();
                return hen;
            } else if (continent.equals(NORTHAMERICA)) {
                hen = new NorthAmericanHen();
                return hen;
            } else if (continent.equals(ASIA)) {
                hen = new AsianHen();
                return hen;
            } else if (continent.equals(AFRICA)) {
                hen = new AfricanHen();
                return hen;
            }
            //write your code here
            return hen;

C. Chiang

Level 18 , Bryan, United States

20 February 2019, 00:22

Thanks for your input. Solved the problems of run time error. Now met with the last two verify problems.

Bill Wu

Level 29 , Wellington, New Zealand

19 February 2019, 09:47

First you need put all the classes in separate files Second int getMonthlyEggCount() should be abstract, only implemented in specific hens. So you don't set a variable of int eggCount in each class, but put the number directly in the implementation of the above method.