RFR: 8306374: (bf) Improve performance of DirectCharBuffer::append(CharSequence[,int,int]) [v4]

[Brian Burkhalter]

On Sat, 22 Apr 2023 14:48:15 GMT, ExE Boss <duke at openjdk.org> wrote:

>> src/java.base/share/classes/java/nio/Direct-X-Buffer.java.template line 452:
>> 
>>> 450: 
>>> 451:     private $Type$Buffer appendChars(CharSequence csq, int start, int end) {
>>> 452:         checkSession();
>> 
>> This template is for direct buffers so I'm not 100% sure that checkSession is needed here. If the session is closed then SMA.copyMemory used in putArray will throw.
>
> This is probably to avoid allocating the temporary `char[] buf` array when the session is known to be closed.

The primary direct buffer constructor is

    // Primary constructor
    //
    Direct$Type$Buffer$RW$(int cap) {                   // package-private

so in general the `segment` will be `null` and checking it provides no value.

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PR Review Comment: https://git.openjdk.org/jdk/pull/13522#discussion_r1177150138