RE: External function binding bug (early binding)

I think this is too marginal a case to justify fixing. I don't often say
that, but one has to draw the line somewhere. The circumvention is to write
a wrapper Java class that handles the situation, and call that instead.

Michael Kay
http://www.saxonica.com/ 

> -----Original Message-----
> From: saxon-help-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@xxxxxxxxxxxxxxxx 
> [mailto:saxon-help-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@xxxxxxxxxxxxxxxx] 
> On Behalf Of 
> Wolfgang Hoschek
> Sent: 22 June 2005 20:59
> To: saxon-help-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@xxxxxxxxxxxxxxxx
> Subject: [saxon] External function binding bug (early binding)
> 
> Hi Mike,
> 
> There is another small bug in the way saxon-8.4 searches and binds  
> Java extension functions.
> It's triggered if there's a public method in an external function  
> class that uses argument types in its signature that are not on the  
> class path, even if that method is not used in any way by the query.  
> In the spirit of late dynamic binding, I think Saxon should not fail  
> here. Rather, it should catch and ignore the relevant exceptions on  
> function binding if the function is never used.
> 
> The case arises if one has a class with various utility extension  
> functions, some of which are typically rarely used, but have  
> dependencies on various third-party libs. If those rare 
> functions are  
> not used, a user should not need to download and include those third- 
> party libs.
> 
> Here's an example to reproduce (assuming you have lucene.jar from  
> http://lucene.apache.org/java/docs/index.html on the classpath at  
> compile time, but not at runtime):
> 
> package nux.xom.tests;
> 
> import org.apache.lucene.analysis.Analyzer;
> 
> public class ExternalFunctionTest {
>      public static String foo(String bar) { return bar; }
>      public static void unused(String baz, Analyzer anal) {} // this  
> method is never used at runtime
> }
> 
> 
> package nux.xom.tests;
> 
> public class ExternalFunctionTestWorkAround {
>      public static String foo(String bar) { return  
> ExternalFunctionTest.foo(bar); }
> }
> 
> 
> This works fine:
> ===========================================
> declare namespace util =  
> "java:nux.xom.tests.ExternalFunctionTestWorkAround";
> util:foo("x")
> 
> 
> [hoschek /Users/hoschek/unix/devel/nux] fire-xquery ext-workaround.xq
> <atomic-value xsi:type="xs:string" xmlns="http://dsd.lbl.gov/nux";  
> xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";>x</atomic-value>
> 
> 
> This triggers the bug:
> ===========================================
> declare namespace util = "java:nux.xom.tests.ExternalFunctionTest";
> util:foo("x")
> 
> 
> [hoschek /Users/hoschek/unix/devel/nux] fire-xquery ext.xq
> Exception in thread "main" java.lang.NoClassDefFoundError: 
> org/apache/ 
> lucene/analysis/Analyzer
>          at java.lang.Class.getDeclaredMethods0(Native Method)
>          at java.lang.Class.privateGetDeclaredMethods(Class.java:1655)
>          at java.lang.Class.privateGetPublicMethods(Class.java:1778)
>          at java.lang.Class.getMethods(Class.java:832)
>          at net.sf.saxon.functions.JavaExtensionLibrary.bind 
> (JavaExtensionLibrary.java:307)
>          at net.sf.saxon.functions.FunctionLibraryList.bind 
> (FunctionLibraryList.java:71)
>          at net.sf.saxon.expr.ExpressionParser.parseFunctionCall 
> (ExpressionParser.java:1732)
>          at net.sf.saxon.expr.ExpressionParser.parseBasicStep 
> (ExpressionParser.java:1234)
>          at net.sf.saxon.expr.ExpressionParser.parseStepExpression 
> (ExpressionParser.java:1149)
>          at net.sf.saxon.expr.ExpressionParser.parseRelativePath 
> (ExpressionParser.java:1089)
>          at net.sf.saxon.expr.ExpressionParser.parsePathExpression 
> (ExpressionParser.java:1075)
>          at net.sf.saxon.expr.ExpressionParser.parseUnaryExpression 
> (ExpressionParser.java:954)
>          at net.sf.saxon.expr.ExpressionParser.parseCastExpression 
> (ExpressionParser.java:625)
>          at 
> net.sf.saxon.expr.ExpressionParser.parseCastableExpression 
> (ExpressionParser.java:600)
>          at net.sf.saxon.expr.ExpressionParser.parseTreatExpression 
> (ExpressionParser.java:581)
>          at  
> net.sf.saxon.expr.ExpressionParser.parseInstanceOfExpression 
> (ExpressionParser.java:563)
>          at  
> net.sf.saxon.expr.ExpressionParser.parseIntersectExpression 
> (ExpressionParser.java:987)
>          at net.sf.saxon.expr.ExpressionParser.parseUnionExpression 
> (ExpressionParser.java:969)
>          at  
> net.sf.saxon.expr.ExpressionParser.parseMultiplicativeExpression 
> (ExpressionParser.java:906)
>          at 
> net.sf.saxon.expr.ExpressionParser.parseAdditiveExpression 
> (ExpressionParser.java:886)
>          at net.sf.saxon.expr.ExpressionParser.parseRangeExpression 
> (ExpressionParser.java:798)
>          at  
> net.sf.saxon.expr.ExpressionParser.parseComparisonExpression 
> (ExpressionParser.java:748)
>          at net.sf.saxon.expr.ExpressionParser.parseAndExpression 
> (ExpressionParser.java:370)
>          at net.sf.saxon.expr.ExpressionParser.parseOrExpression 
> (ExpressionParser.java:352)
>          at net.sf.saxon.expr.ExpressionParser.parseExprSingle 
> (ExpressionParser.java:306)
>          at net.sf.saxon.expr.ExpressionParser.parseExpression 
> (ExpressionParser.java:269)
>          at net.sf.saxon.query.QueryParser.parseQuery 
> (QueryParser.java:144)
>          at net.sf.saxon.query.QueryParser.makeXQueryExpression 
> (QueryParser.java:71)
>          at net.sf.saxon.query.StaticQueryContext.compileQuery 
> (StaticQueryContext.java:254)
>          at nux.xom.xquery.XQuery.<init>(XQuery.java:413)
>          at nux.xom.pool.XQueryFactory.createXQuery 
> (XQueryFactory.java:139)
>          at nux.xom.pool.XQueryFactory.createXQuery 
> (XQueryFactory.java:165)
>          at nux.xom.pool.XQueryFactory.createXQuery 
> (XQueryFactory.java:114)
>          at nux.xom.tests.XQueryCommand.main(XQueryCommand.java:132)
> [hoschek /Users/hoschek/unix/devel/nux]
> 
> 
> 
> -------------------------------------------------------
> SF.Net email is sponsored by: Discover Easy Linux Migration Strategies
> from IBM. Find simple to follow Roadmaps, straightforward articles,
> informative Webcasts and more! Get everything you need to get up to
> speed, fast. http://ads.osdn.com/?ad_id=7477&alloc_id=16492&op=click
> _______________________________________________
> saxon-help mailing list
> saxon-help-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@xxxxxxxxxxxxxxxx
> https://lists.sourceforge.net/lists/listinfo/saxon-help
> 




-------------------------------------------------------
SF.Net email is sponsored by: Discover Easy Linux Migration Strategies
from IBM. Find simple to follow Roadmaps, straightforward articles,
informative Webcasts and more! Get everything you need to get up to
speed, fast. http://ads.osdn.com/?ad_id=7477&alloc_id=16492&op=click