package com.examplehub.utils;

public class StringUtils {
  public static String toString(char[] chars, int offset, int len) {
    StringBuilder builder = new StringBuilder();
    for (int i = offset; i < offset + len; ++i) {
      builder.append(chars[i]);
    }
    return builder.toString();
  }

  public static String toString(byte[] bytes, int offset, int len) {
    StringBuilder builder = new StringBuilder();
    for (int i = offset; i < offset + len; ++i) {
      builder.append(bytes[i]);
    }
    return builder.toString();
  }

  public static String capitalize(String origin) {
    if (origin == null) {
      throw new NullPointerException();
    }
    if (origin.length() == 0) {
      return "";
    }
    return Character.toUpperCase(origin.charAt(0)) + origin.substring(1).toLowerCase();
  }
}