code: public static boolean isAlphanumericSpace(final CharSequence cs) {
          if (cs == null) {
              return false;
          }
          final int sz = cs.length();
          for (int i = 0; i < sz; i++) {
              if (!Character.isLetterOrDigit(cs.charAt(i)) && cs.charAt(i) != ' ') {
                  return false;
              }
          }
          return true;
      }
docs: <p>Checks if the CharSequence contains only Unicode letters, digits
  or space ({@code ' '}).</p>
  
  <p>{@code null} will return {@code false}.
  An empty CharSequence (length()=0) will return {@code true}.</p>
  
  <pre>
  StringUtils.isAlphanumericSpace(null)   = false
  StringUtils.isAlphanumericSpace("")     = true
  StringUtils.isAlphanumericSpace("  ")   = true
  StringUtils.isAlphanumericSpace("abc")  = true
  StringUtils.isAlphanumericSpace("ab c") = true
  StringUtils.isAlphanumericSpace("ab2c") = true
  StringUtils.isAlphanumericSpace("ab-c") = false
  </pre>
  
  @param cs  the CharSequence to check, may be null
  @return {@code true} if only contains letters, digits or space,
  and is non-null
  @since 3.0 Changed signature from isAlphanumericSpace(String) to isAlphanumericSpace(CharSequence)