class Properties<T> {

  @VisibleForTesting
  final String propertyName;
  final Class<T> propertyType;

  @VisibleForTesting
  PropertySupport propertySupport = PropertySupport.instance();

  /**
   * Creates a new <code>{@link Properties}</code>.
   * @param <T> the type of value to extract.
   * @param propertyName the name of the property to be read from the elements of a {@code Iterable}. It may be a nested
   *          property (e.g. "address.street.number").
   * @param propertyType the type of property to extract
   * @throws NullPointerException if the given property name is {@code null}.
   * @throws IllegalArgumentException if the given property name is empty.
   * @return the created {@code Properties}.
   */
  public static <T> Properties<T> extractProperty(String propertyName, Class<T> propertyType) {
    checkIsNotNullOrEmpty(propertyName);
    return new Properties<>(propertyName, propertyType);
  }

  /**
   * Creates a new <code>{@link Properties} with given propertyName and Object as property type.</code>.
   * 
   * @param propertyName the name of the property to be read from the elements of a {@code Iterable}. It may be a nested
   *          property (e.g. "address.street.number").
   * @throws NullPointerException if the given property name is {@code null}.
   * @throws IllegalArgumentException if the given property name is empty.
   * @return the created {@code Properties}.
   */
  public static Properties<Object> extractProperty(String propertyName) {
    return extractProperty(propertyName, Object.class);
  }

  private static void checkIsNotNullOrEmpty(String propertyName) {<FILL_FUNCTION_BODY>}

  @VisibleForTesting
  Properties(String propertyName, Class<T> propertyType) {
    this.propertyName = propertyName;
    this.propertyType = propertyType;
  }

  /**
   * Specifies the target type of an instance that was previously created with {@link #extractProperty(String)}.
   * <p>
   * This is so that you can write:
   * <pre><code class='java'> extractProperty("name").ofType(String.class).from(fellowshipOfTheRing);</code></pre>
   * 
   * instead of:
   * <pre><code class='java'> extractProperty("name", String.class).from(fellowshipOfTheRing);</code></pre>
   *
   * @param <U> the type of value to extract.
   * @param propertyType the type of property to extract.
   * @return a new {@code Properties} with the given type.
   */
  public <U> Properties<U> ofType(Class<U> propertyType) {
    return extractProperty(this.propertyName, propertyType);
  }

  /**
   * Extracts the values of the property (specified previously in <code>{@link #extractProperty(String)}</code>) from the elements
   * of the given <code>{@link Iterable}</code>.
   * @param c the given {@code Iterable}.
   * @return the values of the previously specified property extracted from the given {@code Iterable}.
   * @throws IntrospectionError if an element in the given {@code Iterable} does not have a property with a matching name.
   */
  public List<T> from(Iterable<?> c) {
    return propertySupport.propertyValues(propertyName, propertyType, c);
  }

  /**
   * Extracts the values of the property (specified previously in <code>{@link #extractProperty(String)}</code>) from the elements
   * of the given array.
   * @param array the given array.
   * @return the values of the previously specified property extracted from the given array.
   * @throws IntrospectionError if an element in the given array does not have a property with a matching name.
   */
  public List<T> from(Object[] array) {
    return propertySupport.propertyValues(propertyName, propertyType, wrap(array));
  }
}

    requireNonNull(propertyName, "The name of the property to read should not be null");
    checkArgument(propertyName.length() > 0, "The name of the property to read should not be empty");
  
<no_super_class>