Re: [gogo] Advanced commands / console

Richard S. Hall Fri, 03 Jul 2009 14:47:01 -0700

On 7/3/09 12:10 PM, Guillaume Nodet wrote:

I've checked in the prototype into gogo for further discussion.
See https://svn.apache.org/repos/asf/felix/trunk/gogo/gogo.commands/


Note, I renamed this to:

    https://svn.apache.org/repos/asf/felix/trunk/gogo/commands/

I realized that I had the naming incorrect, even though I changed it acouple of days ago.

I've also fixed the gogo parser a bit as to be slightly more leniant
when parsing the first argument (so that '/' or '-' could be part of
the first argument).

Are you imaging the Karaf "sub-shell" concept being part of Gogo? Icannot say I am a fan of that concept.


-> richard

Feedback welcome !

On Thu, Jul 2, 2009 at 08:24, Guillaume Nodet<[email protected]>  wrote:

For Karaf, I've been working on a prototype to be able to support more
powerful commands in gogo.
The problem with the current way (i.e. one function == one method) is
that it's quite difficult to
  * display help for a command
  * have optional arguments
So what I've done, and this would also benefit Karaf, is based on what
gshell is doing for commands.
It's based on the following interfaces:

public interface Action
{
    Object execute(CommandSession session) throws Exception;
}

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE})
public @interface Command
{
    String scope();

    String name();

    String description() default "";
}

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.FIELD, ElementType.METHOD})
public @interface Argument
{
    String name() default "VAL";

    String description() default "";

    boolean required() default false;

    int index() default 0;

    boolean multiValued() default false;
}

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.FIELD, ElementType.METHOD})
public @interface Option
{
    String name();

    String[] aliases() default {};

    String description() default "";

    boolean required() default false;

    boolean multiValued() default false;

}


So a given command would look like:

@Command(scope = "my", name = "action")
public class MyAction implements Action {

    @Option(name = "-s", aliases = { "--start" })
    boolean start;

   @Argument(name = "ids", required = true, multivalued = true)
   List<Integer>  ids;

   public Object execute(CommandSession session) {
       ...
   }
}


This action has to be wrapped inside a command (implementing the
Function interface) and which will be able to create a new instance of
the action, parse the arguments, populate it, and call it.
In addition the wrapper will detect the use of "-h" or "--help"
arguments and compute / display the help on the console if requested.

Curerntly, what I've done is leveraging blueprint, so I have a custom
namespace (same as we had in karaf/gshell)

    <command-bundle xmlns="http://felix.apache.org/karaf/xmlns/gshell/v1.0.0";>
        <command name="osgi/list">
            <action class="org.apache.felix.karaf.gshell.osgi.ListBundles">
                <property name="blueprintListener" ref="blueprintListener"/>
            </action>
        </command>
    </command-bundle>

This will create a command and register it in the OSGi registry so
that it will be available in the shell.

I haven't implemented completers yet, but that's next on my todo list.

So the question is: should this be part of gogo or do we keep that for karaf ?
I have the same question for the console: I've started working on an
advanced console (leveraging jline as we did in karaf / gshell).

--
Cheers,
Guillaume Nodet
------------------------
Blog: http://gnodet.blogspot.com/
------------------------
Open Source SOA
http://fusesource.com

Re: [gogo] Advanced commands / console

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