Sounds good to me!
Maybe there is an open source framework we could use:
http://www.cyclopsgroup.org/projects/jcli/
Best wishes
Christian
Chris Miller schrieb:
> Something we've done at my current job is to write a CLI framework that makes
> managing command line params very very easy. I think this project could
> benefit
> greatly from this approach due to its large number of (frequently changing?)
> parameters. Unfortunately I can't contribute our code, however I can describe
> in detail what we did and help with the implementation. Basically each
> application
> that uses command line params defines an interface that looks something like
> this:
>
> public interface MkGMapParams {
> @Option(defaultValue = "0", description = "The Family ID for the generated
> map")
> int getFamilyId();
>
> @Option(defaultValue = Option.REQUIRED, description = "The Product ID for
> the generated map")
> int getProductId();
>
> @Option(defaultValue = Option.OPTIONAL, description = "The country the
> map represents")
> String getCountryName();
>
> @Option(description = "Specify this to make cycleways")
> boolean isMakeCycleways();
>
> enum MyEnum { One, Two }
> @Option(name = "custom-enum", defaultValue = "One", description = "My
> custom
> enum")
> MyEnum getEnum();
> // etc
> }
>
> To parse the parameters in code, we basically just make a call to our parser
> as follows:
>
> MkGMapParams params = CliParser.parse(MkGMapParams.class, arguments); //
> where arguments is a String... parameter
>
> That's it, the 'params' object now has all our command line params, parsed
> into the correct type. If any of the parsing failed, error(s) explaining
> what was wrong, along with a list of valid options and descriptions, are
> displayed to the user.
>
> Some valid usage examples:
> java -jar mkgmap --product-id 99 --country-name bhutan --make-cycleways
> java -jar mkgmap --product-id 99 --custom-enum Two
>
> Some invalid usage examples:
> java -jar mkgmap --family-id 99 --country-name bhutan --make-cycleways
> (fails because --product-id is a required parameter)
> java -jar mkgmap --product-id 99 --enum One (fails because the 'enum'
> parameter must be specified as --custom-enum, not --enum)
> java -jar mkgmap --product-id abc (fails because --product-id is not an
> integer)
> java -jar mkgmap --product-id 11 --family-id --make-cycleways (fails because
> no value was specified for --family-id)
>
>
> Here's how it works under the hood:
>
> We have a converter interface defined as follows:
>
> interface Converter<T> {
> T convert(String param) throws Exception; // Convert from the
> string
> provided on the command line to a typesafe object.
> List<String> getValidValues() throws Exception; // Provide a list of valid
> options (optional). eg a list of enum values.
> String getDefaultValue() throws Exception; // Returns the default
> value (or null if the parameter is required).
> }
>
> We then have a map from type to converter class, eg:
>
> defaultConverters.put(String.class, StringConverter.class);
> defaultConverters.put(Integer.class, IntegerConverter.class);
> defaultConverters.put(Integer.type, IntegerConverter.class);
>
> We then use reflection (and the annotation info) to examine the interface
> and determine what the valid parameters are, whether they're required, what
> type they are etc. For each parameter we parse we convert the string to the
> appropriate type using the above map. Once that's done and no errors were
> found, we use Proxy.newProxyInstance() to create an instance of the parameter
> interface for the client application.
>
> Note that we have a lot of additional functionality too like list handling,
> custom converters, inter-parameter dependency handling, custom validation,
> Guice support etc but the above is the guts of it. I hope it doesn't sound
> like too much work - it's really not! The best thing is it will force people
> to clearly define their parameters in the MkGMapParams interface since that's
> the only thing that'll be available anywhere beyond the main() method. It's
> very easy to use once the scaffolding is in place and it makes for nice
> centralised
> management of params and user friendly help and error messages.
>
> Chris
>
>
>
> _______________________________________________
> mkgmap-dev mailing list
> [email protected]
> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
>
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