how text length of a UITextView can be fixed in iphone sdk?

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text

{

    NSUInteger newLength = (text_View.text.length - range.length) + text.length;

    if(newLength <= 140)

    {

        return YES;

    } else {

        NSUInteger emptySpace = 140 - (text_View.text.length - range.length);

        textView.text = [[[textView.text substringToIndex:range.location] 

                          stringByAppendingString:[text substringToIndex:emptySpace]]

                         stringByAppendingString:[textView.text substringFromIndex:(range.location + range.length)]];

        return NO;

    }

}