Sure, take this example:
.addRule()
.when(Selection.exists(XMLFile.class,
"xmls")
.with(Element.DOCTYPE, "
http://maven.apache.org/POM/4.0.0")
)
.perform(Iteration.over(XMLFile.class, "xmls",
"pom"
).as(MavenPomFile.class)
.perform(
Graph.replace(Selection.current(XMLFile.class))
.with(Selection.current(MavenPomFile.class))
)
)
Now consider what would happen if we were to parameterize the DOCTYPE
statement:
.addRule()
.when(Selection.exists(XMLFile.class,
"xmls")
.with(Element.DOCTYPE, "http://
{domain}/POM/4.0.0")
)
What if we want to match some domains and not others? Well, we'll need to
configure the parameter:
> .addRule()
.when(Selection.exists(XMLFile.class,
"xmls")
.with(Element.DOCTYPE, "http://
{domain}/POM/4.0.0")
)
>
.where("domain").matches("(maven.apache.org|
>
jboss.org/maven|example\\.(com|org|net))").convertedBy(new
> URLDomainConverter()).bindsTo(new GraphBinding("xml>domain"))
This would both ensure that the parameter matches only what was contained
in the regular expression, but also adds a converter which stores the value
in the graph (somehow) as a URLDomain (which just for example's sake is a
@VertexFrame annotated interface.) Keep in mind that this is just a
hypothetical example.
The full battery of parameter configuration options are:
.where(String param)
.matches(String regex)
.constrainedBy(Constraint constraint)
.convertedBy(Converter converter)
.validatedBy(Validator validator)
.bindsTo(Binding binding)
.configuredBy(ParameterConfigurator configurator) // can do any of the
above
~Lincoln
On Mon, May 5, 2014 at 11:05 AM, Jess Sightler <jsightle(a)redhat.com> wrote:
Could you explain the "where" clause in more detail here?
I have seen
this a few times in your examples, but I'm not entirely clear on what it is
doing. :)
On 05/05/2014 10:33 AM, Lincoln Baxter, III wrote:
.addRule()
.when() // if
.perform() // then
.otherwise() // else
.where("paramName1").configuredBy(...).where("paramName2") //
configure
parameters
On Mon, May 5, 2014 at 10:23 AM, Lincoln Baxter, III <
lincolnbaxter(a)gmail.com> wrote:
> 1) The (when, perform) structure would be basic for all rules?
>
> Yes, there are actually a few more structures:
>
> .addRule()
> .when() // if
> .perform() // then
> .otherwise() // else
>
>
> 2) This seems like it will build object tree, which will then be
> processed, right? No space for custom code?
>
> You can already do exactly what you just suggested :) Custom code is no
> problem, it just accepts an object like any normal Java code - it's just
> Java.
>
>
> 3) Isn't that a fluent API overuse? How about something like:
>
> I don't know what you are referring to here as overuse, but yes, I am
> exaggerating the use of the fluent API to make a point. The rules could be
> completely un-fluent and still use these same APIs. I'm not sure I see the
> point/difference of the sample you've shown.
>
> 4) .withDoctype("http://maven.apache.org/POM/4.0.0") ?
> doctype is a property... Better .with(PropNames.DOCTYPE,
> "http://maven.apache.org/POM/4.0.0") ?
>
> I agree, some kind of more general structure here would probably be
> better.
>
>
> 5) Could the variable be filled outside .when () ? But perhaps just a
> matter of taste.
>
> Absolutely you could - and yes, it's all a matter of taste :)
>
>
> On Fri, May 2, 2014 at 7:26 PM, Ondrej Zizka <ozizka(a)redhat.com> wrote:
>
>> Hi,
>>
>> WRT rules API, as proposed at
>>
>>
https://github.com/windup/windup/blob/master/engine/config/api/src/main/j...
>>
>> It's nice, with some comments.
>>
>> I know it was typed in a hurry, but anyway:
>>
>> 1) The (when, perform) structure would be basic for all rules?
>>
>> 2) This seems like it will build object tree, which will then be
>> processed, right? No space for custom code?
>>
>> 3) Isn't that a fluent API overuse? How about something like:
>>
>> new ConfigBuilder( ... ){{
>> addRule( new MavenPomRule( this, ... ){
>> boolean when( ) { return Selection.exists(XMLFile.class,
>> "xmls").with("doctype", DOCTYPE_POM); }
>> void perform( MavenPomInfo mpi ){ ... }
>> }
>> );
>> }}.run();
>>
>> It's verbose now but with Java 8 lambdas, it would be less.
>>
>> While it's a bit more verbose, it would have obvious benefits of better
>> debuggability, and would better leverage Java's features like
>> inheritance (imagine AbstractXmlFileRule and it's subclasses for
>> whatever one would want to do with a XML file, having few of its
>> properties passed as parameters.
>>
>> Btw this code above is inspired by Wicket and GWT.
>>
>> 4) .withDoctype("http://maven.apache.org/POM/4.0.0") ?
>> doctype is a property... Better .with(PropNames.DOCTYPE,
>> "http://maven.apache.org/POM/4.0.0") ?
>>
>> 5) Could the variable be filled outside .when () ? But perhaps just a
>> matter of taste.
>>
>> More later when we have some more examples.
>>
>> Nice!
>> Ondra
>> _______________________________________________
>> windup-dev mailing list
>> windup-dev(a)lists.jboss.org
>>
https://lists.jboss.org/mailman/listinfo/windup-dev
>>
>
>
>
> --
> Lincoln Baxter, III
>
http://ocpsoft.org
> "Simpler is better."
>
--
Lincoln Baxter, III
http://ocpsoft.org
"Simpler is better."
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Lincoln Baxter, III
http://ocpsoft.org
"Simpler is better."