RFR: [15] JDK-8236030: Cleanup use of String.toCharArray

[Jonathan Gibbons]

Ivan,

Great suggestion, and sets up the possibility to  use strip() when both 
leading and trailing whitespace should be removed.

The only slight change in semantics would be that these methods work in 
terms of code-points, not characters, and javadoc has not (yet?) been 
adapted to use code-points throughout.

-- Jon


On 12/16/2019 01:23 PM, Ivan Gerasimov wrote:
> Hello!
>
> Can String.stripLeading()/stripTrailing() methods be used instead, or 
> is there a reason to avoid them?
>
> With kind regards,
>
> Ivan
>
>
> On 12/16/19 1:10 PM, Jonathan Gibbons wrote:
>> Please review a tiny change to eliminate a string copy into a 
>> temporary character buffer when removing leading or trailing 
>> whitespace from a string.
>>
>> The affected methods are called within the main code to translate doc 
>> comments to HTML.  This is noreg-cleanup/no-reg-trivial, so no new 
>> additional tests.
>>
>> Webrev below, but the patch is also included here:
>>
>> --- 
>> a/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/HtmlDocletWriter.java 
>> Mon Dec 16 15:33:03 2019 -0500
>> +++ 
>> b/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/HtmlDocletWriter.java 
>> Mon Dec 16 13:07:18 2019 -0800
>> @@ -1604,22 +1604,19 @@
>>      }
>>
>>      private String removeTrailingWhitespace(String text) {
>> -        char[] buf = text.toCharArray();
>> -        for (int i = buf.length - 1; i > 0 ; i--) {
>> -            if (!Character.isWhitespace(buf[i]))
>> -                return text.substring(0, i + 1);
>> +        int i = text.length() - 1;
>> +        while (i >= 0 && Character.isWhitespace(text.charAt(i))) {
>> +            i--;
>>          }
>> -        return text;
>> +        return i == text.length() - 1 ? text : text.substring(0, i + 
>> 1);
>>      }
>>
>>      private String removeLeadingWhitespace(String text) {
>> -        char[] buf = text.toCharArray();
>> -        for (int i = 0; i < buf.length; i++) {
>> -            if (!Character.isWhitespace(buf[i])) {
>> -                return text.substring(i);
>> -            }
>> +        int i = 0;
>> +        while (i < text.length() && 
>> Character.isWhitespace(text.charAt(i))) {
>> +            i++;
>>          }
>> -        return text;
>> +        return i == 0 ? text : text.substring(i);
>>      }
>>
>>      /**
>>
>>
>> -- Jon
>>
>>
>> JBS: https://bugs.openjdk.java.net/browse/JDK-8236030
>> Webrev: http://cr.openjdk.java.net/~jjg/8236030/webrev/
>>