[Metafacture] Regex, conjunction

[Christoph Böhme]

Hi again

support for the <if> statement is now implemented [1] on the
quantors-for-metamorph branch [2]. Please have a play with it and let me
know whether it works and behaves in a sensible and understandable way.

Cheers,
Christoph

[1]
https://github.com/cboehme/metafacture-core/commit/0530d6ad72ced992b479bff94d6f56bbef77bb2d
[2] https://github.com/cboehme/metafacture-core/tree/quantors-for-metamorph


Am 26.11.2013 17:09, schrieb Christoph Böhme:
> Hi Pascal
> 
> I created a branch [1] on my Metafacture fork which contains three new
> Metamorph collectors. These implement quantors to simplify expressing
> conditions in Metamorph. They are called <all>, <any>, and <none>.
> 
> It would be great if you could give them a try and let me know whether
> they are helpful.
> 
> The next step is to add an <if> statement which allows something like
> this to execute a combine only if a condition is met:
> 
> <combine ...>
>   <if>
>     <all>
>       <data ... />
>     </all>
>   </if>
>   <data .. />
> </combine>
> 
> Best,
> Christoph
> 
> [1] https://github.com/cboehme/metafacture-core/tree/quantors-for-metamorph
> 
> 
> Am 24.11.2013 11:11, schrieb Christoph Böhme:
>> Hi Pascal
>>
>> A not-operation can be implemented with the following bit of code inside
>> a combine-element:
>>
>> <choose name="" value="">
>> 	<data source="051.">
>> 		<!-- This is condition B: -->
>> 		<regexp match="(^[^a|])" />
>> 		<constant value="B_MATCHES" />
>> 	</data>
>> 	<data source="_id">
>> 		<!-- This can be any field that is available in all
>> 		     records: -->
>> 		<constant value="B_DOES_NOT_MATCH" />
>> 	</data>
>> 	<postprocess>
>> 		<!-- This bit implements the not-operation. The
>> 		     choose-element only fires if it has NOT selected
>> 		     B_MATCHES: -->
>> 		<equals string="B_DOES_NOT_MATCH" />
>> 	</postprocess>
>> </choose>
>>
>> It is not straight forward but I think it should allow you to write your
>> "A andnot B" condition.
>>
>> Writing Metamorph scripts which include conditions seems to be one of
>> the most unintuitive parts of Metamorph at the moment. I think we should
>> consider implementing a more expressive approach to do this. Using
>> <combine> for this is not really straight-forward. I created an issue
>> for this [1]. The issue outlines two possible ways of implementing it.
>>
>> Best,
>> Christoph
>>
>> [1] https://github.com/culturegraph/metafacture-core/issues/151
>>
>>
>> Am 15.11.2013 11:25, schrieb Christoph, Pascal:
>>> Hi *,
>>>
>>> I don't know how to do this with metamorph:
>>>
>>> "If A andnot B => pass to receiver"
>>>
>>> Details:
>>> Having two entities: entity A has to match a regex, and B has also a regex. The
>>> whole should be true if A matches and B does NOT match[1]. Furthermore, if B
>>> does not exist at all, the whole should also be true.
>>>
>>> Thus far I only managed using function "combine" with parameter
>>> flushWith="record", like this:
>>>
>>> <combine name="foo" value="bar" flushWith="record">
>>> 	<data source="051.">
>>> 		<regexp match="(^[^a|])"/>
>>> 	</data>
>>> 	<data source="050.">
>>> 		<regexp match="^a.*"/>
>>> 	</data>
>>> </combine>
>>>
>>> I got my "foo bar" if:
>>>
>>> - 050. matches AND 051. is missing
>>>
>>> and that's it, because in Regexp.java nothing is fired (aka "passed to
>>> receiver") if the regex does not match. And no, I can't formulate the negative
>>> regex as a positive regex.
>>>
>>> Is there a possibility to do what I want?
>>> I enhanced the Regexp class with :
>>>
>>> if (this.getNamedValueReceiver().getClass().equals(Combine.class) && !match) {
>>> getNamedValueReceiver().receive(name, NO_MATCH, source, recordCount, entityCount);
>>> }
>>>
>>> and adopted the Combine class. It's working , but it does not seem apropriate.
>>> Anything I missed ?
>>>
>>> cheers, pascal
>>> _______________________________________________
>>> Metafacture mailing list
>>> Metafacture at lists.dnb.de
>>> http://lists.dnb.de/mailman/listinfo/metafacture
>>>
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