map nodes of preimage resource and image resources

[lueck]

Keep track of nodes while an DOM resource is transformed.

Implementation is tried on de.wwu.scdh.annotation.selection.resource.MappedDOMResource using different approaches to tracking nodes.

Assignees: @lueck

Migrated from GitLab: https://zivgitlab.uni-muenster.de/SCDH/selectors/selection-engine/-/issues/15

[lueck]

added to epic SCDH&12

[lueck]

Pushing DOM level 3 user data through the transformation was first approach.

See 08d2860 and 1d16ac6.

But user data does make it through the transformation. See
https://saxonica.plan.io/boards/3/topics/9843

[lueck]

The approach based on xdmNode.hashCode() does not work. See 9e4fcb8.

[lueck]

The approach based on evaluating the XPath expression generate-id(.) on the nodes does not work. See d77d4ce.

[lueck]

XSLT seems to let us create attributes on text nodes, at least, it does not throw exceptions:

  <xsl:template match="text()">
    <xsl:copy>
      <xsl:attribute name="tracking:track" select="generate-id(.)"/>
    </xsl:copy>
  </xsl:template>

However, even if such attributes were ever created, they cannot be read even through Saxon's java API.

Tried in 0025af0.

[lueck]

The docs for Xalan state, that it is based on DOM level 3.

Xalan-Java also builds on SAX 2 and DOM level 3. [https://xml.apache.org/xalan-j/]

However, maybe DOM level 3 output is just a serialization feature. See release notes for 2.7.1:

The serializer now has support for DOM Level 3 serialization (LSSerializer) for an XML parser. [https://xml.apache.org/xalan-j/readme.html]

So, before we give this old peace of software a chance, we should investigate further in the source code.

Using Xalan would also only be suitable for xml to plain text transformations, where XSLT 1.0 may be enough.

However, it would be interesting as a proof of concept.

[lueck]

Tracing nodes with attributes holding node IDs and wrapping elements around text nodes work, but require some reflection in the XSLT stylesheets.

Proof of concept in 2059c5a.