fuck

streams/src/streams/Main.java

@@ -1,9 +1,11 @@
 package streams;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
+import javax.swing.text.html.Option;
 import tester.Tester;
 
 class Customer {
@@ -93,34 +95,152 @@ interface PurchaseDB {
     getPurchasesForSince(List<Integer> customerIds, int numberOfDaysAgo);
 }
 
-class Victims implements CustomerDB {
-    Map<Integer, Customer> victims;
-
-    Victims() {}
-
-    public Optional<Customer> getCustomerById(int id) {
-        return Optional.ofNullable(this.victims.get(id));
-    }
-
-    public List<Customer> getAllCustomers() {
-        return this.victims.values().stream().toList();
-    }
-}
-
 class Examples {
     Customer borace, germany, vietnam;
-    Inventory cabbages, cinderBlocks;
+    Inventory cabbages, cinderBlocks, traps;
-    LineItem lottaCabbages, oneCinderBlock;
+    LineItem lottaCabbages, oneCinderBlock, tripleTrap;
-    Purchase profit;
+    Purchase profit, ireland, cob, biden;
+
+    CustomerDB victims;
+    InventoryDB loot;
+    PurchaseDB crimes;
 
     void init() {
         borace = new Customer(0, "Borace");
-        borace = new Customer(0, "Germany");
+        germany = new Customer(1, "Germany");
-        borace = new Customer(0, "Vietnam");
+        vietnam = new Customer(2, "Vietnam");
+
         cabbages = new Inventory(0, "Expensive cabbages.", 28);
         cinderBlocks = new Inventory(1, "Cinder blocks.", 1);
+        traps = new Inventory(2, "Traps.", 10);
+
         lottaCabbages = new LineItem(0, 54);
         oneCinderBlock = new LineItem(1, 1);
+        tripleTrap = new LineItem(2, 3);
+
+        // Borace a day ago.
         profit = new Purchase(0, List.of(lottaCabbages, oneCinderBlock), 0, 1);
+        // Germany four days ago.
+        ireland = new Purchase(1, List.of(oneCinderBlock), 1, 4);
+        // Vietnam five days ago.
+        cob = new Purchase(2, List.of(tripleTrap), 2, 5);
+        // Vietnam today.
+        biden = new Purchase(
+            3, List.of(lottaCabbages, tripleTrap, oneCinderBlock), 2, 0
+        );
+
+        victims = new CustomerDB() {
+            List<Customer> customers = Arrays.asList(borace, germany, vietnam);
+
+            public Optional<Customer> getCustomerById(int id) {
+                // yess use streams for everything...
+                return customers.stream()
+                    .filter(customer -> customer.getId() == id)
+                    .findFirst();
+            }
+
+            public List<Customer> getAllCustomers() { return customers; }
+        };
+
+        loot = new InventoryDB() {
+            List<Inventory> inventory =
+                Arrays.asList(cabbages, cinderBlocks, traps);
+
+            public Optional<Inventory> getInventoryById(int id) {
+                return inventory.stream()
+                    .filter(i -> i.getId() == id)
+                    .findFirst();
+            }
+
+            public List<Inventory> getAllInventory() { return inventory; }
+        };
+
+        crimes = new PurchaseDB() {
+            List<Purchase> purchases =
+                Arrays.asList(profit, ireland, biden, cob);
+
+            public Optional<Purchase> getPurchaseById(int id) {
+                return purchases.stream()
+                    .filter(p -> p.getId() == id)
+                    .findFirst();
+            }
+
+            public List<Purchase> getPurchasesSince(int numberOfDaysAgo) {
+                return purchases.stream()
+                    .filter(p -> p.getNumberOfDaysAgo() <= numberOfDaysAgo)
+                    .toList();
+            }
+
+            public List<Purchase> getPurchasesFor(int customerId) {
+                return purchases.stream()
+                    .filter(p -> p.getCustomerIdOfPurchaser() == customerId)
+                    .toList();
+            }
+
+            public List<Purchase> getPurchasesFor(List<Integer> customerIds) {
+                return purchases.stream()
+                    .filter(
+                        p -> customerIds.contains(p.getCustomerIdOfPurchaser())
+                    )
+                    .toList();
+            }
+
+            public List<Purchase> getPurchasesForSince(
+                int customerId, int numberOfDaysAgo
+            ) {
+                return purchases.stream()
+                    .filter(
+                        p
+                        -> p.getCustomerIdOfPurchaser() == customerId &&
+                               p.getNumberOfDaysAgo() <= numberOfDaysAgo
+                    )
+                    .toList();
+            }
+
+            public List<Purchase> getPurchasesForSince(
+                List<Integer> customerIds, int numberOfDaysAgo
+            ) {
+                return purchases.stream()
+                    .filter(
+                        p
+                        -> customerIds.contains(p.getCustomerIdOfPurchaser()) &&
+                               p.getNumberOfDaysAgo() <= numberOfDaysAgo
+                    )
+                    .toList();
+            }
+        };
+    }
+
+    void test(Tester t) {
+        init();
+
+        t.checkExpect(victims.getCustomerById(0), Optional.of(borace));
+        t.checkExpect(victims.getCustomerById(9), Optional.empty());
+        t.checkExpect(
+            victims.getAllCustomers(), List.of(borace, germany, vietnam)
+        );
+
+        t.checkExpect(loot.getInventoryById(0), Optional.of(cabbages));
+        t.checkExpect(loot.getInventoryById(3), Optional.empty());
+        t.checkExpect(
+            loot.getAllInventory(), List.of(cabbages, cinderBlocks, traps)
+        );
+
+        t.checkExpect(crimes.getPurchaseById(0), Optional.of(profit));
+        t.checkExpect(crimes.getPurchaseById(100000002), Optional.empty());
+        t.checkExpect(crimes.getPurchasesSince(-1), List.of());
+        t.checkExpect(crimes.getPurchasesSince(0), List.of(biden));
+        t.checkExpect(crimes.getPurchasesSince(2), List.of(profit, biden));
+        t.checkExpect(crimes.getPurchasesFor(0), List.of(profit));
+        t.checkExpect(crimes.getPurchasesFor(2), List.of(biden, cob));
+        t.checkExpect(
+            crimes.getPurchasesFor(List.of(0, 2)), List.of(profit, biden, cob)
+        );
+        t.checkExpect(crimes.getPurchasesForSince(0, 0), List.of());
+        t.checkExpect(crimes.getPurchasesForSince(2, 2), List.of(biden));
+        t.checkExpect(
+            crimes.getPurchasesForSince(List.of(0, 1, 2), 9),
+            List.of(profit, ireland, biden, cob)
+        );
     }
 }