chore: comments and formatting

Author: DaFDE31

lesson_09/types/types_app/src/main/java/com/codedifferently/lesson9/Lesson9.java

@@ -24,6 +24,7 @@ public static void main(String[] args) {
     application.run(args);
   }
 
+  @Override
   public void run(String... args) throws Exception {
     if (args.length == 0) {
       return;
@@ -33,6 +34,8 @@ public void run(String... args) throws Exception {
     if (option == null) {
       throw new IllegalArgumentException("Provider name is required");
     }
+
+    // If the option is "--bulk", generate data files for all providers.
     if (option.equals("--bulk")) {
       for (DataProvider provider : providers) {
         String providerName = provider.getProviderName();
@@ -42,6 +45,7 @@ public void run(String... args) throws Exception {
       }
       return;
     }
+
     String path = getDataPath();
     var fileGenerator = new SampleFileGenerator();
     fileGenerator.createTestFile(path, option);

lesson_09/types/types_app/src/main/java/com/codedifferently/lesson9/generator/SampleFileGenerator.java

@@ -44,6 +44,7 @@ private List<ValueGenerator> getShuffledGenerators() {
     return generators;
   }
 
+  // Mapping of classes to value generators
   private static final Map<Class<?>, ValueGenerator> TYPE_TO_GENERATOR =
       Map.of(
           Integer.class, new IntValueGenerator(),
@@ -54,25 +55,49 @@ Boolean.class, new BooleanValueGenerator(),
           String.class, new StringValueGenerator(),
           Double.class, new DoubleValueGenerator());
 
+  /**
+   * Creates a JSON provider file with generated sample data.
+   *
+   * @param path the file path where the provider file will be written
+   * @param providerName the name of the provider
+   * @param provider the {DataProvider} that defines columns
+   * @throws IllegalArgumentException if no generator is found for a column type
+   */
   public void createProviderFile(String path, String providerName, DataProvider provider) {
     var generators = getGenerators(provider);
     ArrayList<Map<String, String>> rows = createSampleData(generators);
+
+    // Writes the generated rows to a JSON file.
     saveToJsonFile(path, providerName, rows);
   }
 
+  /**
+   * Retrieves value generators for each column in the given {@link DataProvider}.
+   *
+   * <p>The column names are expected to follow the format "column1", "column2", ..., "columnN".
+   * Each column type must have a corresponding {@link ValueGenerator} in {@code TYPE_TO_GENERATOR}.
+   * Ensures that the generators are in the same order as the columns in the DataProvider.
+   *
+   * @param provider the provider defining column types
+   * @return a list of value generators, in column order
+   * @throws IllegalArgumentException if no generator is mapped for a column type
+   */
   private List<ValueGenerator> getGenerators(DataProvider provider) {
     Map<String, Class> columnTypes = provider.getColumnTypeByName();
-
     ArrayList<ValueGenerator> generators = new ArrayList<>();
+
     for (int i = 1; i <= columnTypes.size(); i++) {
       String column = "column" + i;
       Class<?> type = columnTypes.get(column);
+
+      // Look up the appropriate generator for this column type.
       ValueGenerator generator = TYPE_TO_GENERATOR.get(type);
       if (generator == null) {
         throw new IllegalArgumentException("No generator found for type: " + type);
       }
       generators.add(generator);
     }
+
     return generators;
   }