refactoring : primitive obsession - replace primitive with object

refactoring/src/main/java/com/example/refactoring/_11_primitive_obsession/_30_replace_primitive_with_object/Order.java

@@ -0,0 +1,17 @@
+package com.example.refactoring._11_primitive_obsession._30_replace_primitive_with_object;
+
+public class Order {
+
+    private final Priority priority;
+
+    public Order(String priorityValue) {
+        this(new Priority(priorityValue));
+    }
+    public Order(Priority priority) {
+        this.priority = priority;
+    }
+
+    public Priority getPriority() {
+        return priority;
+    }
+}

refactoring/src/main/java/com/example/refactoring/_11_primitive_obsession/_30_replace_primitive_with_object/OrderProcessor.java

@@ -0,0 +1,13 @@
+package com.example.refactoring._11_primitive_obsession._30_replace_primitive_with_object;
+
+import java.util.List;
+import java.util.Objects;
+
+public class OrderProcessor {
+
+    public long numberOfHighPriorityOrders(List<Order> orders) {
+        return orders.stream()
+                .filter(o -> o.getPriority().higherThan(new Priority("normal")))
+                .count();
+    }
+}

refactoring/src/main/java/com/example/refactoring/_11_primitive_obsession/_30_replace_primitive_with_object/Priority.java

@@ -0,0 +1,31 @@
+package com.example.refactoring._11_primitive_obsession._30_replace_primitive_with_object;
+
+import java.util.List;
+
+public class Priority {
+
+    private final String value;
+
+    private final List<String> type = List.of("low", "normal", "high", "rush");
+
+    public Priority(String value) {
+        if (type.contains(value)) {
+            this.value = value;
+        } else {
+            throw new IllegalArgumentException("illegal value for priority : " + value);
+        }
+    }
+
+    @Override
+    public String toString() {
+        return this.value;
+    }
+
+    private int index() {
+        return this.type.indexOf(this.value);
+    }
+
+    public boolean higherThan(Priority other) {
+        return this.index() > other.index();
+    }
+}

refactoring/src/main/java/com/example/refactoring/_11_primitive_obsession/_30_replace_primitive_with_object/_before/Order.java

@@ -0,0 +1,14 @@
+package com.example.refactoring._11_primitive_obsession._30_replace_primitive_with_object._before;
+
+public class Order {
+
+    private String priority;
+
+    public Order(String priority) {
+        this.priority = priority;
+    }
+
+    public String getPriority() {
+        return priority;
+    }
+}

refactoring/src/main/java/com/example/refactoring/_11_primitive_obsession/_30_replace_primitive_with_object/_before/OrderProcessor.java

@@ -0,0 +1,12 @@
+package com.example.refactoring._11_primitive_obsession._30_replace_primitive_with_object._before;
+
+import java.util.List;
+
+public class OrderProcessor {
+
+    public long numberOfHighPriorityOrders(List<Order> orders) {
+        return orders.stream()
+                .filter(o -> o.getPriority() == "high" || o.getPriority() == "rush")
+                .count();
+    }
+}

refactoring/src/test/java/com/example/refactoring/_11_primitive_obsession/_30_replace_primitive_with_object/OrderProcessorTest.java

@@ -0,0 +1,22 @@
+package com.example.refactoring._11_primitive_obsession._30_replace_primitive_with_object;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class OrderProcessorTest {
+
+    @Test
+    void numberOfHighPriorityOrders() {
+        OrderProcessor orderProcessor = new OrderProcessor();
+        long highPriorityOrders = orderProcessor.numberOfHighPriorityOrders(
+                List.of(new Order("low"),
+                        new Order("normal"),
+                        new Order("high"),
+                        new Order("rush")));
+        assertEquals(2, highPriorityOrders);
+    }
+
+}