[External] : Re: My experience using Java to do CLI Scripting

[Cay Horstmann]

Il 14/04/25 23:46, Ron Pressler ha scritto:
> 
> 
>> On 14 Apr 2025, at 21:48, Remi Forax <forax at univ-mlv.fr> wrote:
>>
>>
>> Hi Ron,
>> i think you need to close the inputReader
>>
>>   public static String output(String... args) {
>>     ProcessBuilder processBuilder = new ProcessBuilder(args);
>>     try {
>>       Process process = processBuilder.start();
>>       try (BufferedReader reader = process.inputReader()) {
>>         return reader.lines().collect(Collectors.joining("\n"));
>>       }
>>     } catch (IOException e) {
>>       throw new IOError(e);
>>     }
>>   }
> 
> 
> When the process terminates, the InputStream underlying the pipe is closed (after being drained and the unread bytes served by a ByteArrayInputStream), which *I think* should be sufficient, but I could be wrong.
> 
> — Ron

Reading the process output into a string or string stream raises a number of worries.

* Do I need to wait for the process to complete?
* Do I need to close anything?
* How exactly do I use getInputStream()/inputReader() with *extreme care*, as the API doc warns me?

If it is safe to call

   builder.start().inputReader().lines()

or

   builder.start().getInputStream().readAllBytes()

without waiting or closing, then the API doc could say so. If not, then maybe a safe method to get the entire output would be appropriate for Process?


-- 

Cay S. Horstmann | https://horstmann.com