On 16 mai 2011, at 16:06, Matt Benson wrote:
> On Mon, May 16, 2011 at 4:51 AM, Romain Rouvoy <[email protected]> wrote:
>> I'm using JXPath to query a graph of beans, which are heavily using lists,
>> e.g.:
>>> public class A {
>>> List<B> getB() {...}
>>> }
>>>
>>> public class B {
>>> String getName() {...}
>>> List<C> getC() {...}
>>> }
>>>
>>> public class C {
>>> String getName() {...}
>>> }
>>
>> However, when I'm querying this graph of beans, the following request does
>> not match any elements (while it should return several elements):
>>> org.apache.commons.jxpath.JXPathContext.newContext(new A());
>>> context.getValue("b[@name='foo']/c/name");
>> Any idea? Does JXPath support navigation within lists?
> What should happen is that getValue(expr) returns the first value specified
> by your expression, while iterate(expr) would be the way you would retrieve
> multiple results. If you can distill your problem down to a failing JUnit
> test, please feel free to attach this to a JIRA issue.
Thanks Matt, actually I use Scala to develop my application:
> import scala.reflect.BeanProperty
>
> case class B(@BeanProperty val name:String)
>
> object a {
> @BeanProperty val b = List[B](new B("FOOs"), new B("BARs"))
> }
The annotation @BeanProperty is used to generate getters at compile-time.
> scala> val context = org.apache.commons.jxpath.JXPathContext.newContext(a)
> context: org.apache.commons.jxpath.JXPathContext =
> org.apache.commons.jxpath.ri.JXPathContextReferenceImpl@132bb617
>
> scala> context.getValue("b")
> res27: java.lang.Object = List(B(FOOs), B(BARs))
This is an expected behavior...
> scala> context.getValue("b/name")
> org.apache.commons.jxpath.JXPathNotFoundException: No value for xpath: b/name
> at
> org.apache.commons.jxpath.ri.JXPathContextReferenceImpl.getValue(JXPathContextReferenceImpl.java:383)
> at
> org.apache.commons.jxpath.ri.JXPathContextReferenceImpl.getValue(JXPathContextReferenceImpl.java:313)
> at .<init>(<console>:29)
> at .<clinit>(<console>)
> at RequestResult$.<init>(<console>:9)
> at RequestResult$.<clinit>(<console>)
> at RequestResult$scala_repl_result(<console>)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:597)
> at scala.tools.nsc.Interpreter$Request$$a...
According to your answer, I should get a String ("FOOs") and not an exception...
Ideally, I would have expected a collection of String containing "FOOs" and
"BARs"... :)
> scala> val i = context.iterate("b/name")
> i: java.util.Iterator[_] =
> org.apache.commons.jxpath.ri.compiler.Expression$ValueIterator@3b29642c
>
> scala> i.hasNext
> res30: Boolean = false
And even when using the context.iterate method, the returned iterator is
empty...
Is that ok if I submit my Scala code except within JIRA?
Romain
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