BaseX-Talk November 2014

basex-talk@mailman.uni-konstanz.de

35 participants
59 discussions

GUI feature request "Add as import"
by Andy Bunce 03 Jan '16

03 Jan '16

Hi, I often find myself adding module imports in the GUI and I wonder if the following suggestion might speed up that process. Add a new menu item to the filelist right click context menu "Add as import" when the file selection is a XQuery module. The action would be to add a line to the current edit window source with import module namespace {$prefix} = '{$namespace}' at {$path}; Where $prefix and $namespace} are read from the source of the selected file, and $path is calculated from the relative path from the edit file source to the selected filelist source. The line would be inserted at a suitable place in the prologue or at the current location if that is too tricky. /Andy

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Position of matched tokens in a full-text query
by Javier Couto 22 May '15

22 May '15

Hi, Sorry if this is too basic, but I’m trying to get the positions of the matched tokens in a full-text query, and I can’t find the way to do it. I imagine something like: for $sentence in //sentence where $sentence[text() contains text { ‘DNA', ‘oxidation' }] return <positions>ft:SOME-FUNCTION-FOR-TOKENS-POSITIONS($sentence[text() contains text { ‘DNA', ‘oxidation' }])</positions> Is this possible? Thank you in advance, Javier

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Out Of Memory
by Mansi Sheth 06 Jan '15

06 Jan '15

Hello, I have a use case, where I have to extract lots in information from each XML in each DB. Something like, attribute values of most of the nodes in an XML. For such, queries based goes Out Of Memory with below exception. I am giving it ~12GB of RAM on i7 processor. Well I can't complain here since I am most definitely asking for loads of data, but is there any way I can get these kinds of data successfully ? mansi-veracode:BigData mansiadmin$ ~/Downloads/basex/bin/basexhttp BaseX 8.0 beta b45c1e2 [Server] Server was started (port: 1984) HTTP Server was started (port: 8984) Exception in thread "qtp2068921630-18" java.lang.OutOfMemoryError: Java heap space at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.addConditionWaiter(AbstractQueuedSynchronizer.java:1857) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2073) at org.eclipse.jetty.util.BlockingArrayQueue.poll(BlockingArrayQueue.java:342) at org.eclipse.jetty.util.thread.QueuedThreadPool.idleJobPoll(QueuedThreadPool.java:526) at org.eclipse.jetty.util.thread.QueuedThreadPool.access$600(QueuedThreadPool.java:44) at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:572) at java.lang.Thread.run(Thread.java:744) -- - Mansi

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Use xquery:eval or not?
by Marc van Grootel 23 Dec '14

23 Dec '14

Hi, I would like to ask some advice. For my Origami[1] library I'm exploring different ways of providing more powerful selectors for nodes in a template document. As this is for a templating library I would like to offer string based selectors and am considering if I should go for CSS-style selectors or XPath selectors. I started on CSS selectors to be able to select nodes with selectors like "p#id" and "li.class" but to do this properly it involves quite a bit of string manipulation in order to support more advanced stuff. Being in a language that already has XPath in it, it would be much more natural and powerful to use XPath selectors. This led me to look at xquery:eval. So far I resisted using eval but the code is a lot simpler that way. Implementing CSS-style selectors would probably lead me down a path with a lot more ugly string manipulation. I'm aware that it's better to express these things in XQuery code and that is also possible. But it's so much nicer to read this: xf:extract(xf:select('li'), $doc) then this: xf:extract(function($node) { $node/li }, $doc) I'm interested in pros and cons of using xquery:eval with XPath string-selectors. How is the performance? Other downsides (such as being non-standard)? Thanks --Marc [1] https://github.com/xokomola/origami

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What is the best way to implement an async REST method?
by Marc van Grootel 16 Dec '14

16 Dec '14

How would you implement an async REST pattern? I don't remember having seen anything that makes me do this using plain XQuery. Does this mean the only way to tackle this would be via Java and events maybe? I would post to a URL, this URL would accept the post and return a temporary URL where I can check the status of my request, then once it's ready this temp URL will redirect me to the location of the real resource. That's the gist of the async REST pattern that I would like to implement. What would be the best approach to experiment with this? --Marc

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Reg : NegativeArraySizeException
by Chandrasekhar 04 Dec '14

04 Dec '14

Dear Team we are getting the below issue while opening database and replacing the file to the database.Please guide us to resolve the issue. We are using below code to replace the file. Context context = new Context(); LocalSession ls = new LocalSession(context); ls.execute("OPEN DBNAME"); ls.replace("FILENAME",new FileInputStream("FILEPATH")); org.basex.core.BaseXException: Improper use? Potential bug? Your feedback is welcome: Contact: basex-talk(a)mailman.uni-konstanz.de Version: BaseX 7.9 Java: Sun Microsystems Inc., 1.6.0_30 OS: Linux, amd64 Stack Trace: java.lang.NegativeArraySizeException at org.basex.io.random.DataAccess.readBytes(DataAccess.java:216) at org.basex.io.random.DataAccess.readToken(DataAccess.java:194) at org.basex.io.random.DataAccess.readToken(DataAccess.java:185) at org.basex.data.DiskData.txt(DiskData.java:267) at org.basex.data.DiskData.text(DiskData.java:235) at org.basex.index.resource.Docs.paths(Docs.java:106) at org.basex.index.resource.Docs.docs(Docs.java:229) at org.basex.index.resource.Resources.docs(Resources.java:120) at org.basex.core.cmd.Replace.run(Replace.java:51) at org.basex.core.Command.run(Command.java:329) at org.basex.core.Command.execute(Command.java:94) at org.basex.core.Command.execute(Command.java:117) at org.basex.server.LocalSession.execute(LocalSession.java:96) at org.basex.server.LocalSession.replace(LocalSession.java:80) at com.in10s.collectioncreation.CRSXMLDBManager.createCollection(CRSXMLDBManager.java:183) at com.in10s.collectioncreation.CRSCollectionCreator.main(CRSCollectionCreator.java:138) at com.in10s.filewatcher.CRSFileWatcher.main(CRSFileWatcher.java:52) Thanks&Regards ChandraSekhar The information contained in this e-mail and any accompanying documents may contain information that is confidential or otherwise protected from disclosure. If you are not the intended recipient of this message, or if this message has been addressed to you in error, please immediately alert the sender by reply e-mail and then delete this message, including any attachments. Any dissemination, distribution or other use of the contents of this message by anyone other than the intended recipient is strictly prohibited.

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running BaseX 8.0 under OSX 10.6.8?
by C. M. Sperberg-McQueen 02 Dec '14

02 Dec '14

When I attempt to run the copy of BaseX 8.0 I just downloaded under OS X 10.6.8, I get the following error report, which at the moment I am having some trouble deciphering. cmsmcq$ /opt/local/BaseX-8.0/basex/bin/basexgui Exception in thread "main" java.lang.UnsupportedClassVersionError: org/basex/BaseXGUI : Unsupported major.minor version 51.0 at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClassCond(ClassLoader.java:637) at java.lang.ClassLoader.defineClass(ClassLoader.java:621) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141) at java.net.URLClassLoader.defineClass(URLClassLoader.java:283) at java.net.URLClassLoader.access$000(URLClassLoader.java:58) at java.net.URLClassLoader$1.run(URLClassLoader.java:197) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:190) at java.lang.ClassLoader.loadClass(ClassLoader.java:306) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:247) cmsmcq$ Is this telling me that BaseX requires a more recent version of Java than I currently have on this machine? Or is it something else? [Yes, I know, I should upgrade my operating system and possibly my hardware ... someday.] Thanks for any help. -- **************************************************************** * C. M. Sperberg-McQueen, Black Mesa Technologies LLC * http://www.blackmesatech.com * http://cmsmcq.com/mib * http://balisage.net ****************************************************************

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New blog post: Origami - XQuery screen scraping with Extractors
by Marc van Grootel 01 Dec '14

01 Dec '14

It was already up for a while but DNS issues made my blog go missing for almost a week. Now it's back. http://xokomola.com/2014/11/18/xquery-origami-2.html The post describes how to do screen scraping using Origami extractors. I'm quite happy with the outcome. --Marc

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Fold - HTTP routing library
by Marc van Grootel 01 Dec '14

01 Dec '14

Hi, I would like to announce a new library (very alpha) called Fold. https://github.com/xokomola/fold It is a an HTTP routing library which provides an alternative way to map HTTP requests to XQuery functions. In future I hope to use this together with Origami to build REST services and small web apps. My main goal of announcing this is to get feedback on how to improve this. Currently it is defined on top of RESTXQ but in future this might be handled by a Java extension. There are parts missing still and I strongly advise you not to use this for a serious project. Performance gets bad quite quickly. Performance gains may very well be possible by XQuery refactorings. I basically wrote this as a port from a couple of Clojure libraries. A bit of documentation for this library and for Origami can be found in each project's wiki. Note that I only just started these and they are not complete. I'll be working on this library over the next month to get it into a more usable shape. Happy to receive comments and improvements. --Marc

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java.lang.RuntimeException: Insertion at beginning of populated table.
by Andy Bunce 01 Dec '14

01 Dec '14

Hi, With the latest snapshot. running the attached code twice generates the error below. The intent to create or update a database from the data files. Regards /Andy Improper use? Potential bug? Your feedback is welcome: Contact: basex-talk(a)mailman.uni-konstanz.de Version: BaseX 8.0 beta 07cd3e9 Java: Oracle Corporation, 1.7.0_60 OS: Windows 8.1, amd64 Stack Trace: java.lang.RuntimeException: Insertion at beginning of populated table. at org.basex.util.Util.notExpected(Util.java:60) at org.basex.io.random.TableDiskAccess.insert(TableDiskAccess.java:325) at org.basex.data.Data.insert(Data.java:915) at org.basex.data.Data.insert(Data.java:806) at org.basex.data.atomic.Replace.apply(Replace.java:64) at org.basex.data.atomic.AtomicUpdateCache.applyUpdates(AtomicUpdateCache.java:298) at org.basex.data.atomic.AtomicUpdateCache.execute(AtomicUpdateCache.java:282) at org.basex.query.up.DataUpdates.apply(DataUpdates.java:164) at org.basex.query.up.ContextModifier.apply(ContextModifier.java:110) at org.basex.query.up.Updates.apply(Updates.java:133) at org.basex.query.QueryContext.iter(QueryContext.java:348) at org.basex.query.QueryContext.execute(QueryContext.java:590) at org.basex.query.QueryProcessor.execute(QueryProcessor.java:100) at org.basex.core.cmd.AQuery.query(AQuery.java:82) at org.basex.core.cmd.XQuery.run(XQuery.java:22) at org.basex.core.Command.run(Command.java:360) at org.basex.core.Command.execute(Command.java:94) at org.basex.gui.GUI.exec(GUI.java:470) at org.basex.gui.GUI.access$5(GUI.java:427) at org.basex.gui.GUI$8.run(GUI.java:414)

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BaseX-Talk November 2014