Sorry, this is my fault. Current Java annotation doesn't support the extension. But we could use reflection to get the namespaces from your customer annotation. I just did a quick fix for this[1], please check it out.
[1]https://issues.apache.org/activemq/browse/CAMEL-1602 Willem millej wrote: > How would one go about extending the XPath annotation? After searching > around the web it looks as if annotations can't extend another annotation; > in fact, annotations can't use the extends keyword at all. > > If you make the custom "annotation" a regular interface that extends the > XPath annotation interface, the compiler warns that you shouldn't use XPath > as a superinterface, and how would you add a NamespacePrefix to the array > of NamespacePrefixes in the XPath annotation anyway? > > > > willem.jiang wrote: >> Hi >> >> After checking the Camel code, I think the MyXPath need to be extended >> from XPath. >> >> That is because the XPathAnnotationExpressionFactory will check if the >> annotation is the instance of XPath, before it adds the namespace into >> the XPathBuilder. >> >> public class XPathAnnotationExpressionFactory extends >> DefaultAnnotationExpressionFactory { >> >> @Override >> public Expression createExpression(CamelContext camelContext, >> Annotation annotation, LanguageAnnotation languageAnnotation, Class >> expressionReturnType) { >> String xpath = getExpressionFromAnnotation(annotation); >> XPathBuilder builder = XPathBuilder.xpath(xpath); >> if (annotation instanceof XPath) { >> XPath xpathAnnotation = (XPath) annotation; >> NamespacePrefix[] namespaces = xpathAnnotation.namespaces(); >> if (namespaces != null) { >> for (NamespacePrefix namespacePrefix : namespaces) { >> builder = >> builder.namespace(namespacePrefix.prefix(), namespacePrefix.uri()); >> } >> } >> } >> return builder; >> } >> } >> >> Willem >> >> >> millej wrote: >>> The bottom of this page talks about how to use my namespaces in an XPath >>> injection as a parameter. http://camel.apache.org/xpath.html >>> http://camel.apache.org/xpath.html >>> >>> I've tried doing this, but for some reason I still get an exception >>> saying >>> it can't resolve my namespace. >>> >>> Here is my custom XPath annotation (edits to remove company info): >>> >>> @Retention(RetentionPolicy.RUNTIME) >>> @Documented >>> @Target({ElementType.FIELD, ElementType.METHOD, ElementType.PARAMETER}) >>> @LanguageAnnotation(language = "xpath", factory = >>> XPathAnnotationExpressionFactory.class) >>> public @interface MyXPath { >>> String value(); >>> NamespacePrefix[] namespaces() default { >>> @NamespacePrefix(prefix = "soap", uri = >>> "http://www.w3.org/2003/05/soap-envelope";), >>> @NamespacePrefix(prefix = "xsd", uri = >>> "http://www.w3.org/2001/XMLSchema";), >>> @NamespacePrefix(prefix = "bg", uri = >>> "http://mycompany.com/mynamespace";)}; >>> } >>> >>> And my function that uses the custom annotation: >>> >>> @Consume(uri = "activemq:com.mycompany.myqueue") >>> public String myFunction( >>> @Body String inXml, >>> @MyXPath("//bg:elem/@id") String id) { >>> >>> log.info("Id: " + id); >>> log.info("Body: " + inXml); >>> >>> return "<Success/>"; >>> } >>> >>> I couldn't find any examples for custom XPath annotations and the link >>> above >>> is all I could find about it in the documentation. Any help as to what I >>> need to do, or what needs to be done differently, is greatly appreciated. >>> >>> Also, I don't know if it is relevant, but I am using camel inside Fuse >>> Servicemix with these versions: >>> ServiceMix: 3.4.0.0-fuse >>> Camel: 1.5.4.0-fuse >>> Activemq: 5.2.0.2-fuse >>> >>> And the exception: >>> >>> org.apache.camel.builder.xml.InvalidXPathExpression: Invalid xpath: >>> //bg:elem/@id. Reason: javax.xml.xpath.XPathExpressionException >>> at >>> org.apache.camel.builder.xml.XPathBuilder.evaluateAs(XPathBuilder.java:443) >>> at >>> org.apache.camel.builder.xml.XPathBuilder.evaluate(XPathBuilder.java:110) >>> at >>> org.apache.camel.component.bean.MethodInfo$2.evaluate(MethodInfo.java:186) >>> at >>> org.apache.camel.component.bean.MethodInfo.createMethodInvocation(MethodInfo.java:78) >>> at >>> org.apache.camel.component.bean.BeanInfo.createInvocation(BeanInfo.java:100) >>> at >>> org.apache.camel.component.bean.BeanProcessor.process(BeanProcessor.java:103) >>> at >>> org.apache.camel.component.jms.EndpointMessageListener.onMessage(EndpointMessageListener.java:72) >>> at >>> org.springframework.jms.listener.AbstractMessageListenerContainer.doInvokeListener(AbstractMessageListenerContainer.java:543) >>> at >>> org.springframework.jms.listener.AbstractMessageListenerContainer.invokeListener(AbstractMessageListenerContainer.java:482) >>> at >>> org.springframework.jms.listener.AbstractMessageListenerContainer.doExecuteListener(AbstractMessageListenerContainer.java:451) >>> at >>> org.springframework.jms.listener.AbstractPollingMessageListenerContainer.doReceiveAndExecute(AbstractPollingMessageListenerContainer.java:323) >>> at >>> org.springframework.jms.listener.AbstractPollingMessageListenerContainer.receiveAndExecute(AbstractPollingMessageListenerContainer.java:261) >>> at >>> org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.invokeListener(DefaultMessageListenerContainer.java:982) >>> at >>> org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.run(DefaultMessageListenerContainer.java:881) >>> at java.lang.Thread.run(Thread.java:619) >>> Caused by: javax.xml.xpath.XPathExpressionException >>> at >>> com.sun.org.apache.xpath.internal.jaxp.XPathImpl.compile(XPathImpl.java:402) >>> at >>> org.apache.camel.builder.xml.XPathBuilder.createXPathExpression(XPathBuilder.java:465) >>> at >>> org.apache.camel.builder.xml.XPathBuilder.getExpression(XPathBuilder.java:301) >>> at >>> org.apache.camel.builder.xml.XPathBuilder.evaluateAs(XPathBuilder.java:429) >>> ... 14 more >>> Caused by: >>> com.sun.org.apache.xpath.internal.domapi.XPathStylesheetDOM3Exception: >>> Prefix must resolve to a namespace: bg >>> at >>> com.sun.org.apache.xpath.internal.compiler.XPathParser.errorForDOM3(XPathParser.java:653) >>> at >>> com.sun.org.apache.xpath.internal.compiler.Lexer.mapNSTokens(Lexer.java:638) >>> at >>> com.sun.org.apache.xpath.internal.compiler.Lexer.tokenize(Lexer.java:265) >>> at >>> com.sun.org.apache.xpath.internal.compiler.Lexer.tokenize(Lexer.java:96) >>> at >>> com.sun.org.apache.xpath.internal.compiler.XPathParser.initXPath(XPathParser.java:110) >>> at com.sun.org.apache.xpath.internal.XPath.<init>(XPath.java:176) >>> at com.sun.org.apache.xpath.internal.XPath.<init>(XPath.java:264) >>> at >>> com.sun.org.apache.xpath.internal.jaxp.XPathImpl.compile(XPathImpl.java:394) >>> >> >> >
