feat(hw-03): implement Builder pattern

hw-03/project-root/app/src/main/java/org/example/App.java

@@ -4,6 +4,7 @@
 package org.example;
 
 import org.example.adapter.*;
+import org.example.builder.*;
 
 public class App {
   public static void main(String[] args) {
@@ -12,6 +13,7 @@ public class App {
 
   private static void run() {
     checkAdapterPattern();
+    checkBuilderPattern();
   }
 
   private static void checkAdapterPattern() {
@@ -20,4 +22,11 @@ public class App {
 
     target.methodWithoutArguments();
   }
+
+  private static void checkBuilderPattern() {
+    Product product =
+        new ProductBuilder().setFirst("first").setSecond("second").setThird(3).build();
+
+    System.out.println(product);
+  }
 }

hw-03/project-root/app/src/main/java/org/example/builder/Product.java

@@ -0,0 +1,40 @@
+package org.example.builder;
+
+/** Product */
+public class Product {
+  private final String first;
+  private final String second;
+  private final int third;
+
+  public Product(String first, String second, int third) {
+    this.first = first;
+    this.second = second;
+    this.third = third;
+  }
+
+  public String getFirst() {
+    return first;
+  }
+
+  public String getSecond() {
+    return second;
+  }
+
+  public int getThird() {
+    return third;
+  }
+
+  @Override
+  public String toString() {
+    return "Product{"
+        + "first='"
+        + first
+        + '\''
+        + ", second='"
+        + second
+        + '\''
+        + ", third="
+        + third
+        + '}';
+  }
+}

hw-03/project-root/app/src/main/java/org/example/builder/ProductBuilder.java

@@ -0,0 +1,27 @@
+package org.example.builder;
+
+/** Builder */
+public class ProductBuilder {
+  private String first;
+  private String second;
+  private int third;
+
+  public ProductBuilder setFirst(String first) {
+    this.first = first;
+    return this;
+  }
+
+  public ProductBuilder setSecond(String second) {
+    this.second = second;
+    return this;
+  }
+
+  public ProductBuilder setThird(int third) {
+    this.third = third;
+    return this;
+  }
+
+  public Product build() {
+    return new Product(first, second, third);
+  }
+}