[jira] Updated: (JCR-740) Support for the decendant-or-self axis in XPath predicates

["Christoph Kiehl (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/JCR-740?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Christoph Kiehl updated JCR-740:
--------------------------------

    Attachment: patch.txt

This patch is a prototype for supporting jcr:contains calls that use descendent-or-self-axis as their root:

/foo/bar/*[jcr:contains(//*, term)]

It does not support queries which use descendent-or-self-axis on childnodes:

NOT SUPPORTED: /foo/bar/*[jcr:contains(test//*, term)]

Right now it uses a keyword to recognize descendent-or-self-axis queries:

/foo/bar/*[jcr:contains(DESCENDENT_OR_SELF, term)]

We used to have queries like this:

/foo/bar/*[jcr:contains(., term) or jcr:contains(*, term) or jcr:contains(*/*, term)]

In this construct the term query is executed three times which leads to long execution times whereas the query above is much faster because the term query is only executed once.

This is just a prototype and I would like to know what you think about it. The patch needs better integration with the query builder so that we don't need to use a keyword but can use "//*" instead.

> Support for the decendant-or-self axis in XPath predicates
> ----------------------------------------------------------
>
>                 Key: JCR-740
>                 URL: https://issues.apache.org/jira/browse/JCR-740
>             Project: Jackrabbit
>          Issue Type: Improvement
>          Components: xpath
>    Affects Versions: 1.2.1
>            Reporter: Randy Simon
>         Attachments: patch.txt
>
>
> For example,
> I want to find the root of a node tree that contains a node with a specified id. The child node may be n layers deep in the node tree. In my specific case, I know how deep it is so
> //element(*, my:foo)[bar/*/*/*/*/@jcr:uuid = 'abc']
> finds the node of type my:foo that contains the child node with id 'abc'.
> Now, I would like to generalize this so I thought i could simply do the following.
> //element(*, my:foo)[bar//*/@jcr:uuid = 'abc']
> but this does not work.

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