Add missing JavaDoc

modules/random/src/main/java/org/stubit/random/DigitSystem.java

@@ -5,25 +5,44 @@
 /** Represents a digit system (a list of digits). */
 public class DigitSystem {
 
+  /** The (western) Arabic digit system. */
   public static final DigitSystem ARABIC =
       new DigitSystem(List.of('0', '1', '2', '3', '4', '5', '6', '7', '8', '9'));
+
+  /** The Eastern Arabic digit system. */
   public static final DigitSystem EASTERN_ARABIC =
       new DigitSystem(List.of('٠', '١', '٢', '٣', '٤', '٥', '٦', '٧', '٨', '٩'));
+
+  /** The Persian digit system. */
   public static final DigitSystem PERSIAN =
       new DigitSystem(List.of('۰', '۱', '۲', '۳', '۴', '۵', '۶', '۷', '۸', '۹'));
+
+  /** The Chinese digit system. */
   public static final DigitSystem CHINESE =
       new DigitSystem(List.of('〇', '一', '二', '三', '四', '五', '六', '七', '八', '九'));
+
+  /** The Japanese digit system. */
   public static final DigitSystem JAPANESE =
       new DigitSystem(List.of('〇', '一', '二', '三', '四', '五', '六', '七', '八', '九'));
+
+  /** The roman digit system. */
   public static final DigitSystem ROMAN =
       new DigitSystem(List.of('Ⅰ', 'Ⅴ', 'Ⅹ', 'Ⅼ', 'Ⅽ', 'Ⅾ', 'Ⅿ'));
 
   private final List<Character> digits;
 
+  /**
+   * Creates a digit system with the provided list of digits.
+   *
+   * @param digits the list of digits in this digit system
+   */
   public DigitSystem(List<Character> digits) {
     this.digits = digits;
   }
 
+  /**
+   * @return the list of digit characters in this digit system
+   */
   public List<Character> digits() {
     return digits;
   }

modules/random/src/main/java/org/stubit/random/RandomChoice.java

@@ -6,8 +6,6 @@
 import java.util.Collection;
 import java.util.List;
 import java.util.Map;
-import java.util.stream.IntStream;
-import java.util.stream.Stream;
 
 /** Randomly select an element from a collection of choices. */
 public class RandomChoice {
@@ -49,10 +47,6 @@ public static <T> T anyOf(T... choices) {
     return aChoiceFrom(choices).build();
   }
 
-  public static <T> T anyOf(Stream<T> choices) {
-    return aChoiceFrom(choices).build();
-  }
-
   /**
    * Randomly selects an element from the values of the provided choices {@link Enum} class.
    *
@@ -102,14 +96,6 @@ public static <T extends Enum<?>> Builder<T> aChoiceFromValuesOf(Class<? extends
     return aChoiceFrom(Arrays.asList(enumType.getEnumConstants()));
   }
 
-  public static <T> Builder<T> aChoiceFrom(Stream<T> choices) {
-    return new Builder<>(choices.toList());
-  }
-
-  public static Builder<Integer> aChoiceFrom(IntStream choices) {
-    return new Builder<>(choices.boxed().toList());
-  }
-
   /** Randomly selects an element from a collection of choices. */
   public static class Builder<T> {
 
@@ -128,6 +114,7 @@ private Builder(Collection<T> choices) {
      * Add the provided additional choices to the selection
      *
      * @param additionalChoices the additional choices
+     * @return this
      */
     public Builder<T> and(Collection<T> additionalChoices) {
       this.choices.addAll(additionalChoices);
@@ -138,6 +125,7 @@ public Builder<T> and(Collection<T> additionalChoices) {
      * Add the provided additional choices to the selection
      *
      * @param additionalChoices the additional choices
+     * @return this
      */
     @SafeVarargs
     public final Builder<T> and(T... additionalChoices) {

modules/random/src/main/java/org/stubit/random/RandomInt.java

@@ -2,6 +2,7 @@
 
 import java.security.SecureRandom;
 
+/** Generates random integers. */
 public class RandomInt {
 
   private RandomInt() {}

modules/random/src/main/java/org/stubit/random/RandomString.java

@@ -57,6 +57,7 @@ public static String aLetterFrom(Alphabet alphabet) {
   }
 
   /**
+   * @param number the number of letters to generate
    * @param alphabet the {@link Alphabet} to select a character from
    * @return a randomly selected character from the provided {@link Alphabet}.
    */