public int indexOf(CharSequence match, int head)
public final int indexOf(CharSequence match)
  public int indexOf(CharSequence match, int head)  {    int length = length();    int matchLength = match.length();    if (matchLength <= 0)      return -1;    else if (head < 0)      return -1;        int end = length - matchLength;    char first = match.charAt(0);    loop:    for (; head <= end; head++) {      if (charAt(head) != first)	continue;      for (int i = 1; i < matchLength; i++) {	if (charAt(head + i) != match.charAt(i))	  continue loop;      }      return head;    }    return -1;  }