RFR: 8159855: Create an SPI for tools

[Robert Field]

On 10/04/16 20:24, Jonathan Gibbons wrote:
> Hi Robert,
>
> When you invoke jshell from the command line through the command line 
> launcher, there must surely be a simpler entry point that is invoked.  
> Command line entry points don't provide Java Preferences objects, for 
> example. That being said, I agree that jshell does require an input 
> stream, and that is not supported by this SPI.

This is how main calls that entry-point --

     public static void main(String[] args) throws Exception {
         new JShellTool(System.in, System.out, System.err, System.out,
                  System.out, System.err,
                  Preferences.userRoot().node("tool/JShell"),
                  Locale.getDefault())
                 .start(args);
     }

The only additional parameter needed to match this form of use would be: 
InputStream in.

>
> If you want a richer API, why do you not export a public API for 
> others to access and use?

The tool is currently in: jdk.internal.jshell.tool

We don't want the tool to be an API.

We could change the package to not be internal and then have one class 
with one method -- but that seems overkill.

I'd much rather find a way that it could fit with what you are developing.

-Robert



>
> -- Jon
>
>
>
> On 10/4/16 6:37 PM, Robert Field wrote:
>> I like the idea of this SPI.  And I'd like the jshell tool to 
>> launchable in this manner,
>>
>> Unfortunately the shape of the SPI would not allow for this. The 
>> current entry-point (which is in an internal package) is --
>>
>>     /**
>>      * The constructor for the tool (used by tool launch via main and 
>> by test
>>      * harnesses to capture ins and outs.
>>      * @param cmdin command line input -- snippets and commands
>>      * @param cmdout command line output, feedback including errors
>>      * @param cmderr start-up errors and debugging info
>>      * @param console console control interaction
>>      * @param userin code execution input, or null to use IOContext
>>      * @param userout code execution output  -- System.out.printf("hi")
>>      * @param usererr code execution error stream  -- 
>> System.err.printf("Oops")
>>      * @param prefs preferences to use
>>      * @param locale locale to use
>>      */
>>     public JShellTool(InputStream cmdin, PrintStream cmdout, 
>> PrintStream cmderr,
>>             PrintStream console,
>>             InputStream userin, PrintStream userout, PrintStream 
>> usererr,
>>             Preferences prefs, Locale locale)
>>
>> Some of these could defaulted, but not all.
>>
>> Any ideas?
>>
>> Thanks,
>> Robert
>>
>>
>>
>> On 10/04/16 16:46, Jonathan Gibbons wrote:
>>> Resend with non-mostly-empty subject line!
>>>
>>> -- Jon
>>>
>>> On 10/04/2016 04:39 PM, Jonathan Gibbons wrote:
>>>> Core-libs folk,
>>>>
>>>> Please review the following change to add a new service provider class
>>>>     java.util.spi.ToolProvider
>>>>
>>>> which can be used provide simple "command-line" access to select JDK
>>>> tools, without starting a new JVM.
>>>>
>>>> The following tools are updated to provide access through the new SPI:
>>>>     javac, javadoc, javap, jdeps
>>>>
>>>> It is expected that additional tools will also be updated to 
>>>> provide access,
>>>> but that will be done separately.
>>>>
>>>> Compiler-dev folk may wish to review the changes to the langtools 
>>>> repository.
>>>>
>>>> JBS: https://bugs.openjdk.java.net/browse/JDK-8159855
>>>> Webrev: http://cr.openjdk.java.net/~jjg/8159855/webrev.03/
>>>> API: 
>>>> http://cr.openjdk.java.net/~jjg/8159855/api.02/java/util/spi/ToolProvider.html
>>>>
>>>> -- Jon
>>>
>>
>