[Add] new strategy

src/main/java/com/github/tiennm99/lotterygenerator/BaseOnDateLotteryGenerator.java

@@ -0,0 +1,48 @@
+package com.github.tiennm99.lotterygenerator;
+
+import java.time.LocalDate;
+import java.time.format.DateTimeFormatter;
+import java.time.format.DateTimeParseException;
+import java.util.HashSet;
+import java.util.Random;
+import java.util.Set;
+
+public class BaseOnDateLotteryGenerator implements LotteryGenerator {
+
+  private static final DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyyMMdd");
+
+  /** yyyyMMdd */
+  private String date;
+
+  private String getDate() {
+    if (date == null) {
+      var currentDate = LocalDate.now();
+      return currentDate.format(formatter);
+    }
+    return date;
+  }
+
+  public void setDate(String date) {
+    try {
+      LocalDate.parse(date, formatter);
+    } catch (DateTimeParseException e) {
+      System.out.println("Input date is not valid.");
+      return;
+    }
+    this.date = date;
+  }
+
+  @Override
+  public Set<Integer> generateNumbers(int totalNumber, int numNumber) {
+    var date = getDate();
+    var dateNumber = Integer.parseInt(date);
+    var random = new Random(dateNumber);
+
+    var result = new HashSet<Integer>();
+    while (result.size() < numNumber) {
+      var number = random.nextInt(totalNumber);
+      result.add(number);
+    }
+    return result;
+  }
+}

src/test/java/com/github/tiennm99/lotterygenerator/BaseOnDateLotteryGeneratorTest.java

@@ -0,0 +1,42 @@
+package com.github.tiennm99.lotterygenerator;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+class BaseOnDateLotteryGeneratorTest {
+  @Test
+  void testMega645() {
+    var generator = new BaseOnDateLotteryGenerator();
+    var numbers = generator.generateNumbers(45, 6);
+    System.out.println(numbers);
+    assertEquals(6, numbers.size());
+    for (int number : numbers) {
+      assertTrue(number >= 1 && number <= 45);
+    }
+  }
+
+  @Test
+  void testMega655() {
+    var generator = new BaseOnDateLotteryGenerator();
+    generator.setDate("20231024");
+    var numbers = generator.generateNumbers(55, 6);
+    System.out.println(numbers);
+    assertEquals(6, numbers.size());
+    for (int number : numbers) {
+      assertTrue(number >= 1 && number <= 55);
+    }
+  }
+
+  @Test
+  void testSetInvalidDate() {
+    var generator = new BaseOnDateLotteryGenerator();
+    generator.setDate("20231313");
+    var numbers = generator.generateNumbers(55, 6);
+    System.out.println(numbers);
+    assertEquals(6, numbers.size());
+    for (int number : numbers) {
+      assertTrue(number >= 1 && number <= 55);
+    }
+  }
+}