Question

1. Create a new project in BlueJ and name it LastName-lab8-appstore, e.g., Smith-lab8-appstore.
2. If your App class from Lab 4 is fully functional, copy it into the project. (You can drag a file from File Explorer onto the BlueJ project window.) Otherwise, use the instructor's App class:
   • Create a new class using the "New Class..." button and name it App.
   • Open the App class to edit the source code. Select and delete all the source code so that the file is empty.
   • Copy in the starting source code found here: Lab 8: App Starting Source Code. (This link will not work for you until you have received feedback on Lab 4. Email the instructor if you think you should be able to access it but can't.)
3. Create an AppStore class and copy in the starting source code found here: Lab 8: AppStore Starting Source Code.
4. For this lab, you will be editing the AppStore class. You should not change the App class for this lab.
5. In AppStore, update the header comment block and document your changes as you work. Use the javadoc tags @param and @return in method header comments as appropriate.
6. As usual, adhere to Java style guidelines as described in Appendix J.
7. Complete the TODOs in the AppStore code, modifying and implementing methods as described. Be sure to follow the specifications as given in the TODO comments.
8. Before submitting your project, delete the TODO comments. TODOs represent a task that still needs to be done, and when you complete a TODO it should be removed. There should not be any TODOs in your submitted project (unless you didn't complete the project).
9. As usual, you should be testing as you go to make sure everything works!

   AppStore Class Starting Source Code
   
   import java.util.ArrayList;
   
   /**
    * An app store containing apps
    * 
    * Modifications:
    * CT: Create AppStore with a list of apps and basic methods to add, clear, and print apps
    *
    * @author Cara Tang
    * @version 2018.02.17
    */
   public class AppStore
   {
       private String appStoreName;
       private ArrayList<App> appList;
       
       /**
        * Create an app store with the given name
        * @param name the name of this app store
        */
       public AppStore(String name)
       {
           appStoreName = name;
           appList = new ArrayList<App>();
       }
       
       /**
        * Populate the store with a few apps.
        * Use this method to make testing easier. After creating an AppStore,
        * call this method to populate the apps, and then test your methods.
        */
       public void populateApps()
       {
           addApp("Pandora Music", "Pandora", 0);
           addApp(new App("Minecraft", "Mojang", 6.99, 3));
           // TODO: ------------------------ 1 --------------------------
           // TODO: Add a few more apps.
       }
       
       /**
        * Add the given app to the app store
        * @param anApp an app to add
        */
       public void addApp(App anApp)
       {
           appList.add(anApp);
       }
       
       /**
        * Create an app with the given name, author, and price and add it to the store.
        * The app starts out unrated.
        * @param name name of the app
        * @param author the app author
        * @param price the price of the app
        */
       public void addApp(String name, String author, double price)
       {
           appList.add(new App(name, author, price));
       }
       
       /**
        * @return the number of apps in the store
        */
       public int getNumberOfApps()
       {
           return appList.size();
       }
       
       /**
        * Removes all the apps from the store
        */
       public void clearAppStore()
       {
           appList.clear();
       }
       
       /**
        * Print all the apps in the store
        */
       public void printAppList()
       {
           System.out.println("============= " + appStoreName + " =============");
           if (appList.size() == 0) {
               System.out.println("No apps in the store");
           }
           else {
               for (App currentApp : appList) {
                   currentApp.printAppInfo();
               }
           }
           System.out.println("===========================================");
       }
   
       /**
        * Find an app based on its name
        * @param name the name of the app to search for
        * @return the app with the given name
        *         or null if there is no app with that name
        */
       // public App findApp(String name)
       // {
           // TODO: ------------------------ 2 --------------------------
           // TODO: Uncomment the method wrapper and implement according to the header comment.
           // TODO: Do not change the method signature that is given.
           // TODO: Hint: One approach is to use a for-each to loop over each app in the list.
           // TODO: Inside the loop check if the app name matches and if so, return the app.
           // TODO: If the loop completes without returning, the app is not in the list and 
           // TODO: you can return null.
       // }
       
       // TODO: ------------------------ 3 --------------------------
       // TODO: Write a method called removeApp that takes a String parameter.
       // TODO: and removes the app with that name.
       // TODO: Hint: ArrayList has a remove method that takes an object that is the element
       // TOOD: to remove. You can call findApp to find the app to remove, and pass it to remove.
       
       // TODO: ------------------------ 4 --------------------------
       // TODO: Write a method called getAppsByAuthor that takes a String parameter
       // TODO: and returns a list of apps by the given author.
       // TODO: If there are no apps with that author, return an empty list (not null).
       // TODO: Do not print anything in this method.
       // TODO: Hint: The structure of this method will be the same as the getUnsold method
       // TODO: from the Auction project.
       
       // TODO: ------------------------ 5 --------------------------
       // TODO: Write a method called getNumAppsWithRating that takes an int parameter
       // TODO: representing a rating, and returns the number of apps in the app store
       // TODO: that have the given rating.
       // TODO: Example: If two apps in the store have rating 3, then the call
       // TODO: getNumAppsWithRating(3) will return 2.
       
       // OPTIONAL TODO: ------------------------ 6 --------------------------
       // OPTIONAL TODO: This TODO is optional.
       // OPTIONAL TODO: Write a method called getMaxRatingOfAnApp (no parameters) that
       // OPTIONAL TODO: returns the maximum rating of an app in the app store.
       // OPTIONAL TODO: Example: If the store has 3 apps, one with rating 2 and two unrated,
       // OPTIONAL TODO: then the max rating is 2.
   
       // TODO: ------------------------ 7 --------------------------
       // TODO: Write a method called printAppStoreSummaryStats (no parameters, no return)
       // TODO: that prints the name of the app store, the total number of apps, the number of
       // TODO: apps of each rating, and the number of unrated apps.
       // TODO: If you implemented getMaxRatingOfAnApp, print the max rating as well.
       // TODO: Sample output:
       // ======== SUMMARY STATS for Joe's App Store ========
       // Total # of apps: 3
       // # apps rated 4: 0
       // # apps rated 3: 0
       // # apps rated 2: 1
       // # apps rated 1: 0
       // # of unrated apps: 2
       // Max rating: 2
       // ===========================================
   
   }

Answer 1

App.java

public class App {
private String name, author;
private double price;
private int rating;
  
public App()
{
this.name = "";
this.author = "";
this.price = 0;
this.rating = 0;
}
  
public App(String name, String author, double price)
{
this.name = name;
this.author = author;
this.price = price;
}

public App(String name, String author, double price, int rating)
{
this.name = name;
this.author = author;
this.price = price;
this.rating = rating;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getAuthor() {
return author;
}

public void setAuthor(String author) {
this.author = author;
}

public double getPrice() {
return price;
}

public void setPrice(double price) {
this.price = price;
}

public int getRating() {
return rating;
}

public void setRating(int rating) {
this.rating = rating;
}
  
public void printAppInfo()
{
System.out.println("Name: " + getName()
+ ", Author: " + getAuthor()
+ ", Price: $" + String.format("%.2f", getPrice())
+ ", Rating: " + getRating());
}
}

AppStore.java

import java.util.ArrayList;

public class AppStore {
private String appStoreName;
private ArrayList<App> appList;
  
/**
* Create an app store with the given name
* @param name the name of this app store
*/
public AppStore(String name)
{
appStoreName = name;
appList = new ArrayList<App>();
}
  
/**
* Populate the store with a few apps.
* Use this method to make testing easier. After creating an AppStore,
* call this method to populate the apps, and then test your methods.
*/
public void populateApps()
{
addApp(new App("Pandora Music", "Pandora", 4.45, 0));
addApp(new App("Minecraft", "Mojang", 6.99, 3));
addApp(new App("Soltaire", "Mojang", 3.53, 3));
addApp(new App("Facebook", "Facebook Inc", 12.33, 4));
addApp(new App("Instagram", "Instagram Corp", 6.29, 4));
addApp(new App("Cred", "Dreamplug", 3.50, 4));
addApp(new App("The Tour", "Pandora", 4.00, 0));
}
  
/**
* Add the given app to the app store
* @param anApp an app to add
*/
public void addApp(App anApp)
{
appList.add(anApp);
}
  
/**
* Create an app with the given name, author, and price and add it to the store.
* The app starts out unrated.
* @param name name of the app
* @param author the app author
* @param price the price of the app
*/
public void addApp(String name, String author, double price)
{
appList.add(new App(name, author, price));
}
  
/**
* @return the number of apps in the store
*/
public int getNumberOfApps()
{
return appList.size();
}
  
/**
* Removes all the apps from the store
*/
public void clearAppStore()
{
appList.clear();
System.out.println("App Store has been wiped out of all apps!");
}
  
/**
* Print all the apps in the store
*/
public void printAppList()
{
System.out.println("======================= " + appStoreName + " =======================");
if (appList.isEmpty()) {
System.out.println("No apps in the store");
}
else {
for (App currentApp : appList) {
currentApp.printAppInfo();
}
}
System.out.println("================================================================");
}
  
/**
* Find an app based on its name
* @param name the name of the app to search for
* @return the app with the given name
* or null if there is no app with that name
*/
public App findApp(String name)
{
int index = 0;
boolean found = false;
  
for(int i = 0; i < appList.size(); i++)
{
if(appList.get(i).getName().equals(name))
{
found = true;
index = i;
break;
}
}
if(found)
return appList.get(index);
else
return null;
}
  
/**
* Remove an app based on its name
* @param name the name of the app to search for
*
*/
public void removeApp(String name)
{
if(findApp(name) == null)
System.out.println("There is no App with the name: " + name);
else
{
appList.remove(findApp(name));
System.out.println("App with the name " + name + " was removed successfully!");
}
}
  
/**
* Returns a list of Apps with the given Author name
* @param authorName the name of the author to search for
* @return a list of apps with the given author name
* or null if there is no author with the name
*/
public ArrayList<App> getAppsByAuthor(String authorName)
{
ArrayList<App> apps = new ArrayList<>();
boolean found = false;
for(int i = 0; i < appList.size(); i++)
{
if(appList.get(i).getAuthor().equals(authorName))
{
found = true;
apps.add(appList.get(i));
}
}
if(!found)
return null;
else
return apps;
}
  
/**
* Returns a list of Apps with the given Author name
* @param rate the app rating as a reference
* @return number of apps with a rating equal to "rate"
*/
public int getNumAppsWithRating(int rate)
{
int numOfApps = 0;
for(int i = 0; i < appList.size(); i++)
{
if(appList.get(i).getRating() == rate)
numOfApps++;
}
return numOfApps;
}
  
/**
* Returns the maximum rating an App has
*/
public int getMaxRatingOfAnApp()
{
int maxRating = appList.get(0).getRating();
for(int i = 0; i < appList.size(); i++)
{
if(appList.get(i).getRating() > maxRating)
maxRating = appList.get(i).getRating();
}
return maxRating;
}
  
/**
* Prints a statistical summary of all the apps in the app store
*/
public void printAppStoreSummaryStats()
{
System.out.println("============= SUMMARY STATS FOR " + appStoreName + " =============");
System.out.println("Total # of apps: " + getNumberOfApps());
System.out.println("# apps rated 4: " + getNumAppsWithRating(4));
System.out.println("# apps rated 3: " + getNumAppsWithRating(3));
System.out.println("# apps rated 2: " + getNumAppsWithRating(2));
System.out.println("# apps rated 1: " + getNumAppsWithRating(1));
System.out.println("# of unrated apps: " + getNumAppsWithRating(0));
System.out.println("Max rating: " + getMaxRatingOfAnApp());
System.out.println("=============================================================");
}
}

AppStoreMain.java (Main class)

import java.util.ArrayList;

public class AppStoreMain {
  
public static void main(String[]args)
{
// create an instance of the App Store class
AppStore appStore = new AppStore("Joe's App Store");
  
// populate the app store with some apps
appStore.populateApps();
  
// manually add 2 apps: unrated
appStore.addApp(new App("Nykaa", "Nykaa Corp", 9.77));
appStore.addApp(new App("CamScanner", "INTSIG Info", 8.47));
  
// prints all apps in the app store
System.out.println("Displaying all apps in the store...");
appStore.printAppList();
  
// finding an app with it's name
System.out.println("\nFinding two apps with names...");
App app1 = appStore.findApp("Cred");
App app2 = appStore.findApp("InstEdu");
if(app1 != null)
app1.printAppInfo();
else
System.out.println("No such app found!");
  
if(app2 != null)
app1.printAppInfo();
else
System.out.println("No such app found!");
  
// removing an app from the store
System.out.println("\nRemoving 2 apps from the store...");
appStore.removeApp("Cred");
appStore.removeApp("InstaEdu");
appStore.printAppList();
  
// get apps by a particular author
System.out.println("\nDisplaying apps by aparticular author name...");
ArrayList<App> appsByAuthor = appStore.getAppsByAuthor("Pandora");
if(appsByAuthor != null)
{
for(App apps : appsByAuthor)
{
apps.printAppInfo();
}
}
  
// printing app store summary stats
System.out.println("\nPrinting summary stats for the app store...");
appStore.printAppStoreSummaryStats();
}
}

******************************************************************** SCREENSHOT *******************************************************

un: Displaying all apps in the store. . . Joe's App Store Name : Pandora Music, Author: Pandora, Price : 두4.45, Rating : 0 Name: Minecraft, Author: Mojang, Price: $6.99, Rating: 3 Name : Soltaire, Author : Mojang, Price: $3.53, Rating: 3 Name : Facebook, Author: Facebook Inc, Price : 두12.33, Rating : 4 Name: Instagram, Author: Instagram Corp, Price: $6.29, Rating 4 Name: Cred, Author Dreamplug, Price: $3.50, Rating: 4 Name: The Tour, Author Pandora, Price $4.00, Rating: 0 Name Nykaa, Author Nykaa Corp, Price $9.77, Rating: 0 Name: CamScanner, Author: INTSIG Info, Price: 두 8.47, Rating: 0 Finding two apps with names.. Name : Cred, Author: Dreamplug, Price: $3.50, Rating : 4 No such app found! Removing 2 apps from the store... App with the name Cred was removed successfully! There is no App with the name: InstaEdu Joe's App Store Name : Pandora Music, Author: Pandora, Price : 두4.45, Rating : 0 Name: Minecraft, Author: Mojang, Price: $6.99, Rating: 3 Name : Soltaire, Author : Mojang, Price: $3.53, Rating: 3 Name : Facebook, Author: Facebook Inc, Price : 두12.33, Rating : 4 Name: Instagram, Author: Instagram Corp, Price: $6.29, Rating 4 Name: The Tour, Author Pandora, Price $4.00, Rating: 0 Name Nykaa, Author Nykaa Corp, Price $9.77, Rating: 0 Name: CamScanner, Author: INTSIG Info, Price: 두 8.47, Rating: 0

Displaying apps by aparticular author name. - Name: Pandora Music, Author: Pandora, Price $4.45. Rating: 0 Name: The Tour, Author: Pandora, Price: $4.00, Rating: 0 Printing summary stats for the app store SUMMARY STATS FOR Joe 's App Store ーーーーーーーーーーーーー ーーーーーーーーーーーーー Total # of apps : 8 # apps rated 4: 2 # apps rated 3: 2 # apps rated 2: 0 # apps rated 1: 0 # f unrated apps: Max rating: 4 BUILD SUCCΞSSFUL (total time: 0 seconds )