RFR: 8354724: BufferedReader readAllLines and readString methods [v5]

[Chen Liang]

On Fri, 18 Apr 2025 15:02:56 GMT, Glavo <duke at openjdk.org> wrote:

>> public static String readString() throws IOException {
>>         char[] chars = new char[TRANSFER_BUFFER_SIZE];
>>         int n;
>>         int off = 0;
>>         int rest = chars.length;
>>         while ((n = read(chars, off, rest)) != -1) {
>>             off += n;
>>             if (n == rest) {
>>                 chars = Arrays.copyOf(chars, chars.length * 2);
>>             }
>>             rest = chars.length - off;
>>         }
>>         return new String(chars, 0, off);
>>     }
>> 
>> Maybe this version is better, it directly expands the capacity on char[] without using StringBuilder, has good performance, and does not need to add new methods.
>
> Maybe it can be implemented by referring to `InputStream::readNBytes(int)` (The default implementation of `InputStream::readAllBytes()` is based on it):
> 
> https://github.com/openjdk/jdk/blob/22e8a97a1ce4e1c781fbc6f1e271c477fe95f069/src/java.base/share/classes/java/io/InputStream.java#L396-L458

If accumulation of array is necessary, I think the "variable sized array" in #24232 may help/

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PR Review Comment: https://git.openjdk.org/jdk/pull/24728#discussion_r2050753970