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https://issues.apache.org/jira/browse/DIGESTER-143?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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i30817 updated DIGESTER-143:
----------------------------
Description:
When one tag is a substring of another tag and both are used as xml patterns,
such as:
"rdf:RDF/pgterms:etext/dc:creator"
"rdf:RDF/pgterms:etext/dc:creator/rdf:Bag/rdf:li" (instances in a collection of
creators)
the callback to the first is called once with empty strings ("") as the body of
the tag if it encounters a instance of the second tag.
If additionally the first tag has a argument
"rdf:RDF/pgterms:etext/dc:creator rdf:type="Literal"" and you bind things
correctly for a two arguments callback with the text body and the argument
value ("Literal"), the callback of the first will be called with a null
rdf:type argument and a empty string as the body. You can use this to
distinguish the bogus callback as a workaround, but requires a additional bean
method and confusing binding too.
The best thing would be if these empty strings callback were avoidable. I can
just test for empty string in the callback, however, i'm trying also to create
assertions on the xml content (including, no empty strings).
If the bogus callback must exist, one of the ways to make it obvious and
distinguishable, would be to use null as the default value, instead of "". No
xml document will have the computation null value, unless some very strange
java binding is happening, in which case, you're asking for trouble. "" is even
worse, because it is common to both domains.
So RFE:
1) Avoid the bogus callback of the smaller xml tree branch if you can.
2) if you can't, use null as a default value instead of the indistinguishable
"".
3) if 2) document this behavior in the javadoc and the digester FAQ.
was:
When one tag is a substring of another tag and both are used as xml patterns,
such as:
"rdf:RDF/pgterms:etext/dc:creator"
"rdf:RDF/pgterms:etext/dc:creator/rdf:Bag/rdf:li" (instances in a collection of
creators)
the callback to the first is called once with empty strings ("") as the body of
the tag if it encounters a instance of the second tag.
If additionally the first tag has a argument
"rdf:RDF/pgterms:etext/dc:creator rdf:type="Literal"" and you bind things
correctly for a two arguments callback with the text body and the argument
value ("Literal"), the callback of the first will be called with a null
rdf:type argument and a empty string as the body. You can use to distinguish
the bogus callback as a workaround, but requires a additional bean method and
confusing binding too.
The best thing would be if these empty strings callback were avoidable. I can
just test for empty string in the callback, however, i'm trying also to create
assertions on the xml content (including, no empty strings).
If the bogus callback must exist, one of the ways to make it obvious and
distinguishable, would be to use null as the default value, instead of "". No
xml document will have the computation null value, unless some very strange
java binding is happening, in which case, you're asking for trouble. "" is even
worse, because it is common to both domains.
So RFE:
1) Avoid the bogus callback of the smaller xml tree branch if you can.
2) if you can't, use null as a default value instead of the indistinguishable
"".
3) if 2) document this behavior in the javadoc and the digester FAQ.
> Unintuitive, possibly broken behaviour.
> ---------------------------------------
>
> Key: DIGESTER-143
> URL: https://issues.apache.org/jira/browse/DIGESTER-143
> Project: Commons Digester
> Issue Type: Improvement
> Affects Versions: 2.1
> Environment: Linux 64 bits
> Reporter: i30817
> Priority: Minor
>
> When one tag is a substring of another tag and both are used as xml patterns,
> such as:
> "rdf:RDF/pgterms:etext/dc:creator"
> "rdf:RDF/pgterms:etext/dc:creator/rdf:Bag/rdf:li" (instances in a collection
> of creators)
> the callback to the first is called once with empty strings ("") as the body
> of the tag if it encounters a instance of the second tag.
> If additionally the first tag has a argument
> "rdf:RDF/pgterms:etext/dc:creator rdf:type="Literal"" and you bind things
> correctly for a two arguments callback with the text body and the argument
> value ("Literal"), the callback of the first will be called with a null
> rdf:type argument and a empty string as the body. You can use this to
> distinguish the bogus callback as a workaround, but requires a additional
> bean method and confusing binding too.
> The best thing would be if these empty strings callback were avoidable. I can
> just test for empty string in the callback, however, i'm trying also to
> create assertions on the xml content (including, no empty strings).
> If the bogus callback must exist, one of the ways to make it obvious and
> distinguishable, would be to use null as the default value, instead of "". No
> xml document will have the computation null value, unless some very strange
> java binding is happening, in which case, you're asking for trouble. "" is
> even worse, because it is common to both domains.
> So RFE:
> 1) Avoid the bogus callback of the smaller xml tree branch if you can.
> 2) if you can't, use null as a default value instead of the indistinguishable
> "".
> 3) if 2) document this behavior in the javadoc and the digester FAQ.
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