Inventory Expiration Tracker

12 points

This question gives you a question-specific abstract class and a question-specific interface. Your class must extend one and implement the other.

Create an abstract class PerishableItem in PerishableItem.java:

Protected fields: String batchId, String itemName.
Constructor: PerishableItem(String batchId, String itemName).
Getters: getBatchId(), getItemName().
Abstract method: public abstract int daysUntilExpiry(); (may be 0 or negative when already expired).

Create an interface Expirable in Expirable.java:

Abstract method: int shelfDaysLeft();
Default method: default boolean isExpiring(int windowDays): returns true when shelfDaysLeft() <= windowDays (inclusive — already-expired items always count).
Default method: default boolean isExpired(): returns true when shelfDaysLeft() <= 0.

Create a class DairyBatch in DairyBatch.java that extends PerishableItem and implements Expirable:

Private fields: int shelfLifeDays, int ageDays.
Constructor: DairyBatch(String batchId, String itemName, int shelfLifeDays, int ageDays) calling super.
daysUntilExpiry() returns shelfLifeDays - ageDays (this can be negative).
shelfDaysLeft() must return the same value as daysUntilExpiry().

Edge cases to think about (not in the sample): the expiring window is inclusive; 0 days left means expired; a negative value (already spoiled) is both expired and expiring; a fresh item is neither.

Sample Run

DairyBatch b = new DairyBatch("B01", "Whole Milk", 10, 7);
System.out.println("Days until expiry: " + b.daysUntilExpiry());
System.out.println("Expiring within 7: " + b.isExpiring(7));
System.out.println("Expired: " + b.isExpired());

Expected Output

Days until expiry: 3
Expiring within 7: true
Expired: false

Test Cases

VisibleTest 1 [Visible] (Sample Run)
Days-until-expiry, inclusive expiring window, and not-yet-expired.
Hidden6 hidden tests
Additional edge cases run when you grade, but their details are not shown.

Java 25

Press Compile & Run to compile and execute your code (OpenJDK 25). Output appears here.