Strategy design pattern.

demo/02/src/main/java/pl/amu/edu/demo/logic/ApartmentHousingStrategy.java

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+package pl.amu.edu.demo.logic;
+
+import lombok.AccessLevel;
+import lombok.RequiredArgsConstructor;
+import lombok.experimental.FieldDefaults;
+import pl.amu.edu.demo.data.Housing;
+import pl.amu.edu.demo.data.WeWillStealYourFlatCheckResult;
+import pl.amu.edu.demo.providers.AverageQuoteProvider;
+
+@RequiredArgsConstructor
+@FieldDefaults(level = AccessLevel.PRIVATE, makeFinal = true)
+public class ApartmentHousingStrategy implements HousingStrategy {
+
+    AverageQuoteProvider provider;
+
+    @Override
+    public WeWillStealYourFlatCheckResult checkEligibility(Housing housing) {
+        return WeWillStealYourFlatCheckResult.ELIGIBLE;
+    }
+}

demo/02/src/main/java/pl/amu/edu/demo/logic/HouseHousingStrategy.java

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+package pl.amu.edu.demo.logic;
+
+import pl.amu.edu.demo.data.Housing;
+import pl.amu.edu.demo.data.WeWillStealYourFlatCheckResult;
+
+public class HouseHousingStrategy implements HousingStrategy{
+    @Override
+    public WeWillStealYourFlatCheckResult checkEligibility(Housing housing) {
+        return WeWillStealYourFlatCheckResult.NOT_ELIGIBLE;
+    }
+}

demo/02/src/main/java/pl/amu/edu/demo/logic/HousingStrategy.java

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+package pl.amu.edu.demo.logic;
+
+import pl.amu.edu.demo.data.Housing;
+import pl.amu.edu.demo.data.WeWillStealYourFlatCheckResult;
+import pl.amu.edu.demo.providers.AverageQuoteProvider;
+
+public interface HousingStrategy {
+
+    WeWillStealYourFlatCheckResult checkEligibility(Housing housing);
+
+    static HousingStrategy getInstance(Housing housing, AverageQuoteProvider provider) {
+        return housing.isApartment ? new ApartmentHousingStrategy(provider) : new HouseHousingStrategy();
+    }
+
+}

demo/02/src/main/java/pl/amu/edu/demo/logic/WeWillStealYourFlatProduct.java

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+package pl.amu.edu.demo.logic;
+
+import pl.amu.edu.demo.data.Person;
+import pl.amu.edu.demo.data.WeWillStealYourFlatCheckResult;
+import pl.amu.edu.demo.providers.AverageQuoteProvider;
+
+public class WeWillStealYourFlatProduct {
+
+    private final AverageQuoteProvider provider;
+
+    public WeWillStealYourFlatProduct(AverageQuoteProvider provider) {
+        this.provider = provider;
+    }
+
+    public WeWillStealYourFlatCheckResult check(Person person) {
+        var strategy = HousingStrategy.getInstance(person.housing, provider);
+        return strategy.checkEligibility(person.housing);
+    }
+
+}