RFR 8071479: Stream and lamdification improvements to j.u.regex.Matcher

[Xueming Shen]

On 02/27/2015 10:34 AM, Paul Sandoz wrote:
> On Feb 27, 2015, at 7:18 PM, Xueming Shen<xueming.shen at oracle.com>  wrote:
>
>> Hi Paul,
>>
>> 1133      * @param  replacer
>> 1134      *         The function to be applied to the match result of this matcher
>> 1135      *         that returns a replacement string.
>> 1136      *
>> 1137      *<p>   The function should not modify this matcher's state during
>> 1138      *         replacement.  This method will, on a best-effort basis, throw a
>> 1139      *         {@link java.util.ConcurrentModificationException} if such
>> 1140      *         modification is detected.
>> 1141      *
>> 1142      *<p>   The state of the match result is guaranteed to be constant
>> 1143      *         only for the duration of the function call and only if the
>> 1144      *         function does not modify this matcher's state.
>>
>>
>> 1151      * @throws ConcurrentModificationException if it is detected, on a
>> 1152      *         best-effort basis, that the replacer function modified this
>> 1153      *         matcher's state
>>
>>
>> Just wonder from API point of view, in theory the replacer should not be able to modify
>> this matcher's state via a MatchResult, it is the side-effect of our implementation detail
>> that happens to return "this matcher" as a MatchResult. For example, it should be possible
>> to simply return a wrapper MatchResult on top of this matcher to only expose the read-only
>> MatchResult methods, so the "replacer" will never be possible to modify the "matcher".
>>
> It's not really about casting a MatchResult to Matcher it's about the function capturing the Matcher instance and operating on it.
>

The "replacer" does not have an explicit reference to the matcher... and
from the implementation it is not really about the "replacer" to change the
state of the matcher, but the matcher's state gets changed during "replacing"?
it might be more clear/obvious to move those warning notes up to the method
doc as "the matcher state should not be updated/changed during the replaceAll
is invoked..."?

-sherman