common interface for accessing context

[Krille]

Hi,

when writing author mode operations I can use AuthorAccess.getDocumentController().evaluateXPath(...) for evaluating an XPath expression on the current document. When writing a schema manager filter I can use context.executeXPath(...) from ro.sync.contentcompletion.xml.Context for evaluating expressions.

Is there an interface, I can use from both ends? I'd like to share more code between author mode operations and cc for text mode.

Using ro.sync.contentcompletion.xml.Context is not as convenient as the interfaces for writing author mode actions, but it would nevertheless be cool to be able to access it from AuthorAccess.

Regards,
Chris

[Radu]

Hi Chris,

As you sensed the Schema Manager Filter is designed to work with both the Text and Author editing modes. So it does not have references to the AuthorAccess.
The "Context" API has this method "ro.sync.contentcompletion.xml.Context.executeXPath(String, String[], boolean)" and then the AuthorDocumentController has this API "ro.sync.ecss.extensions.api.AuthorDocumentController.evaluateXPath(String, boolean, boolean, boolean)" which would both return DOM nodes so you may try to use these methods to reuse code.

Regards,
Radu

[Krille]

Hi Radu!

Thanks for the clearance. I see.

I was wondering about the return type of "ro.sync.contentcompletion.xml.Context.executeXPath(String, String[], boolean)" which according to the API docs (and my IDE) is an non-parametrized "java.util.List".
So I use "java.util.List<Object>" as usual for results of DOM operations. It's much clearer now.

Thanks and regards,
Chris

[Radu]

Hi Chris,

The list of items returns by the XPath (which we run using the Saxon XSLT engine) are usually DOM nodes but they can also be strings for example if you run XPaths which return simple strings.

Regards,
Radu

[Krille]

Hi Radu,

your hint in the first answer, to use the returned DOM nodes, is very instructive. I now pass the document node and an xpath expression for identifying the current node over to a PluginLoader class, which is called from both sides (the schema manager filter and the author mode operation). In that PluginLoader class, Saxon's XPath implementation is used to evaluate expressions on the passed in document node.

However, that only works with the document node passed in from the author mode action. Evaluating the same expression on the document node passed in from the schema manager filter (Context.executeXPath("/", namespaces, true)), fails with an exception:

Code: Select all

javax.xml.xpath.XPathExpressionException: Supplied node must be built using the same or a compatible Configuration

The document node I get from Context.executeXPath("/", namespaces, true) is of type net.sf.saxon.dom.DocumentOverNodeInfo while the one returned by AuthorAccess.getDocumentController().evaluateXPath(...) is of type ro.sync.ecss.dom.wrappers.AuthorDocumentDomWrapper

I already tried to pass a configuration to Saxon XPathFactoryImpl, but that failed to:

Code: Select all

// setup XPath 2.0 from Saxon
XPathFactoryImpl xpathFactoryImpl = new XPathFactoryImpl();
xpathFactoryImpl.setConfiguration((Configuration) document.getDomConfig());
XPath xpath = xpathFactoryImpl.newXPath();

where document is an org.w3c.dom.Document and net.sf.saxon.xpath.XPathFactoryImpl is used.

Code: Select all

java.lang.NullPointerException: Cannot invoke "net.sf.saxon.Configuration.setProcessor(net.sf.saxon.Configuration$ApiProvider)" because "config" is null
	at net.sf.saxon.xpath.XPathFactoryImpl.setConfiguration(XPathFactoryImpl.java:61) ~[oxygen-patched-saxon-9.jar:?]

How can Saxon be used to evaluate XPath expressions on DocumentOverNodeInfo? Is there a Configuration object, I can get e.g. from some utility?
I would also be fine, if Saxon's trees where passed to my PluginLoader class instead of DOM nodes.

Kind Regards,
Chris

[alex_jitianu]

Hi Chris,

net.sf.saxon.dom.DocumentOverNodeInfo.getDomConfig() returns null by design and is not the configuration you need anyway. Thy using net.sf.saxon.dom.NodeOverNodeInfo.getUnderlyingNodeInfo() and net.sf.saxon.om.NodeInfo.getConfiguration() instead to get teh Saxon configuration object.

Best regards,
Alex

[Krille]

Hi Alex,

Nice! That works. Thanks!

It's time to share the code with the community now:
https://github.com/SCDH/oxbytei

Regards,
Chris

[alex_jitianu]

Hi Chris,

We have a blog page that presents various third party frameworks and I can add an entry for oxbytei, if it's O.K. with you.
https://blog.oxygenxml.com/topics/Oxyge ... works.html

Best regards,
Alex

[Krille]

Hi Alex,

yes, that'd be nice!

Happy new year,
Chris