learn-co-curriculum / java-mod-4-sorting-lab

Sorting Lab

Instruction

NOTE: The junit test classes won't compile until after tasks 1-3 are completed.

TASK #1:

The StockItem class represents a concession item sold at a movie theater. Each stock item is uniquely identified by the sku (stock keeping unit). The quantityOnHand indicates the available amount of inventory for the item.

The main method in StockItemMain creates an array of StockItem objects and calls Arrays.sort to sort the array elements. The program will throw an exception if executed because StockItem does not implement java.lang.Comparable.

Update the StockItem class to implement the java.lang.Comparable interface. The class should override compareTo to compare stock item objects based on quantityOnHand.

Rerun the main method in StockItemMain and confirm the output:

Sorted by quantity on hand:[
StockItem{sku='bev-cup-36oz', quantityOnHand=50}, 
StockItem{sku='bev-cup-24oz', quantityOnHand=100}, 
StockItem{sku='m&m-3oz', quantityOnHand=320}]

TASK #2: Do not modify the Movie class.

The Movie class has instance variables title, releaseYear, and distributor. We might want to sort movies by title, year of release, or by distributor. Let's start by creating a comparator to sort by the year of release.

Create a new class YearComparator that implements java.util.Comparator, overriding the compare method to compare two movies by the release year.

Edit the main method in SortMovieMain to sort the array using a YearComparator class instance. Print the array contents after sorting the array.

Arrays.sort(movies, new YearComparator());
System.out.println("Sort movies by year of release: " +  Arrays.toString(movies));

Rerun the main method in SortMovieMain and confirm the output:

Sort movies by year of release: [
Movie{title='The Lord of the Rings: The Two Towers', releaseYear=2002, distributor='New Line Cinema'}, 
Movie{title='Cars', releaseYear=2006, distributor='Walt Disney Pictures'}, 
Movie{title='Thor, Love and Thunder', releaseYear=2022, distributor='Walt Disney Pictures'}, 
Movie{title='Top Gun: Maverick', releaseYear=2022, distributor='Paramount Pictures'}]

TASK #3:

Create a second class named TitleComparator that implements java.util.Comparator. The new comparator should compare movies by their title.

Update the main method in SortMovieMain appending additional lines of code to sort by title:

Arrays.sort(movies, new TitleComparator());
System.out.println("Sort movie by title: " +  Arrays.toString(movies));

Rerun the main method in SortMovieMain and confirm the new comparator sorts the array by title:

Sort movie by title: [
Movie{title='Cars', releaseYear=2006, distributor='Walt Disney Pictures'}, 
Movie{title='The Lord of the Rings: The Two Towers', releaseYear=2002, distributor='New Line Cinema'}, 
Movie{title='Thor, Love and Thunder', releaseYear=2022, distributor='Walt Disney Pictures'}, 
Movie{title='Top Gun: Maverick', releaseYear=2022, distributor='Paramount Pictures'}]

Task #4:

Run the 3 Junit test classes in the test/java folder to confirm the correct implementation.

• StockItemTest
• YearComparatorTest
• TitleComparatorTest