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beginner question
by Paul Phillips
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Hi there
bit of a beginner question here. I have a situation where I want to - get some xml from a jms queue - send an id contained in the xml to a custom component i have written (the body of the request should be a string that looks like this: "ID=blah", so I use a bean to grab the id using xpath and change the body of the exchange) - this will return a message with a body that looks like "MATCHED=TRUE" or something - if MATCHED=TRUE then I want to send some xml to a different endpoint. However this final xml will be using stuff from the original xml that has been "discarded" on the way (? I am not even sure about this) What is the best way to go about getting this "old" data? hope it makes sense. I'm probably missing something really simple I know. A snippet from my route at the moment looks roughly like this: from("direct:deleteRoute").bean(Normalise.class, "getID").enrich("ioe:test:test1").choice().when(body().contains("MATCHED=TRUE").to("ioe:test3"); where ioe uri's refer to my own custom component Hope all this makes sense! Thanks Paul. |
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Re: beginner question
by James.Strachan
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2009/10/23 Paul Phillips <djphillyp@...>:
> > Hi there > > bit of a beginner question here. > > I have a situation where I want to > > - get some xml from a jms queue > - send an id contained in the xml to a custom component i have written (the > body of the request should be a string that looks like this: "ID=blah", so I > use a bean to grab the id using xpath and change the body of the exchange) > - this will return a message with a body that looks like "MATCHED=TRUE" or > something > - if MATCHED=TRUE then I want to send some xml to a different endpoint. BTW you can do the above like this... public class MyBean { @Consume(uri="activemq:SomeQueue") pubilc void onXml(@XPath("/foo/ID") String myID, Document restOfBody) { // return the transformed payload return "MATCHED=TRUE" } } Notice Camel can do the XPath for you and inject the ID parameter to your transformer method (myID) - also notice the lack of any middleware APIs etc. for more details see http://camel.apache.org/pojo-consuming.html -- James ------- http://macstrac.blogspot.com/ Open Source Integration http://fusesource.com/ |
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Re: beginner question
by Claus Ibsen-2
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On Fri, Oct 23, 2009 at 6:35 PM, Paul Phillips <djphillyp@...> wrote:
> > Hi there > > bit of a beginner question here. > > I have a situation where I want to > > - get some xml from a jms queue > - send an id contained in the xml to a custom component i have written (the > body of the request should be a string that looks like this: "ID=blah", so I > use a bean to grab the id using xpath and change the body of the exchange) > - this will return a message with a body that looks like "MATCHED=TRUE" or > something > - if MATCHED=TRUE then I want to send some xml to a different endpoint. > > However this final xml will be using stuff from the original xml that has > been "discarded" on the way (? I am not even sure about this) > > What is the best way to go about getting this "old" data? > > hope it makes sense. I'm probably missing something really simple I know. > > A snippet from my route at the moment looks roughly like this: > > from("direct:deleteRoute").bean(Normalise.class, > "getID").enrich("ioe:test:test1").choice().when(body().contains("MATCHED=TRUE").to("ioe:test3"); > > where ioe uri's refer to my own custom component > > Hope all this makes sense! > Yeah the route example helps :) Your custom component could store the answer as a header then you can keep the original message along the way. However you can also in fact the the original input message from the Camel API Message original = exchange.getUnitOfWork().getOriginalMessage(); Object body = original.getBody(); But other people just store the payload as an Exchange property then they can always grab it back later on demand .setProperty("foo", body()) .// do something else // and now restore the body back .setBody(property("foo")) > Thanks > Paul. > > > -- > View this message in context: http://www.nabble.com/beginner-question-tp26029591p26029591.html > Sent from the Camel - Users mailing list archive at Nabble.com. > > -- Claus Ibsen Apache Camel Committer Author of Camel in Action: http://www.manning.com/ibsen/ Open Source Integration: http://fusesource.com Blog: http://davsclaus.blogspot.com/ Twitter: http://twitter.com/davsclaus |
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Re: beginner question
by Paul Phillips
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Ok great.
From this I've now realised that what I really want to do is grab a bunch of stuff from the incoming xml and store it as properties on the message for future use in the route and then I don't really need the original xml anymore. Now I could write some code like this: DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance(); domFactory.setNamespaceAware(true); // never forget this! DocumentBuilder builder = domFactory.newDocumentBuilder(); Document doc = builder.parse(theIncomingXML); XPathFactory factory = XPathFactory.newInstance(); XPath xpath = factory.newXPath(); XPathExpression expr = xpath.compile("//book[author='Neal Stephenson']/title/text()"); Object result = expr.evaluate(doc, XPathConstants.NODESET); and store the result objects as properties on the message. Is there an "easier" way to do this with Camel? If I am in a class that implements Processor, in the process method, can I access the xpath "helper" stuff that camel provides so that I can just (almost) say String interestingText = message.xpath("//book[author='Neal Stephenson']/title/text()") and it'll handle the parsing etc for me?
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Re: beginner question
by Claus Ibsen-2
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On Wed, Oct 28, 2009 at 2:58 PM, Paul Phillips <djphillyp@...> wrote:
> > Ok great. > > From this I've now realised that what I really want to do is grab a bunch of > stuff from the incoming xml and store it as properties on the message for > future use in the route and then I don't really need the original xml > anymore. > > Now I could write some code like this: > > DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance(); > domFactory.setNamespaceAware(true); // never forget this! > DocumentBuilder builder = domFactory.newDocumentBuilder(); > Document doc = builder.parse(theIncomingXML); > > XPathFactory factory = XPathFactory.newInstance(); > XPath xpath = factory.newXPath(); > XPathExpression expr > = xpath.compile("//book[author='Neal Stephenson']/title/text()"); > > Object result = expr.evaluate(doc, XPathConstants.NODESET); > > and store the result objects as properties on the message. > > Is there an "easier" way to do this with Camel? If I am in a class that > implements Processor, in the process method, can I access the xpath "helper" > stuff that camel provides so that I can just (almost) say > > String interestingText = message.xpath("//book[author='Neal > Stephenson']/title/text()") > > and it'll handle the parsing etc for me? Yeah as you work in a Processor where you have the Exchange object handy Something like this. You may need to tweak it a bit. String interestingText = xpath("//book[author='Neal Stephenson']/title/text()").evaluate(exchange, String.class); > > > > > > > James.Strachan wrote: >> >> 2009/10/23 Paul Phillips <djphillyp@...>: >>> >>> Hi there >>> >>> bit of a beginner question here. >>> >>> I have a situation where I want to >>> >>> - get some xml from a jms queue >>> - send an id contained in the xml to a custom component i have written >>> (the >>> body of the request should be a string that looks like this: "ID=blah", >>> so I >>> use a bean to grab the id using xpath and change the body of the >>> exchange) >>> - this will return a message with a body that looks like "MATCHED=TRUE" >>> or >>> something >>> - if MATCHED=TRUE then I want to send some xml to a different endpoint. >> >> BTW you can do the above like this... >> >> public class MyBean { >> >> @Consume(uri="activemq:SomeQueue") >> pubilc void onXml(@XPath("/foo/ID") String myID, Document restOfBody) { >> // return the transformed payload >> return "MATCHED=TRUE" >> } >> } >> >> Notice Camel can do the XPath for you and inject the ID parameter to >> your transformer method (myID) - also notice the lack of any >> middleware APIs etc. >> >> for more details see >> http://camel.apache.org/pojo-consuming.html >> >> -- >> James >> ------- >> http://macstrac.blogspot.com/ >> >> Open Source Integration >> http://fusesource.com/ >> >> > > -- > View this message in context: http://www.nabble.com/beginner-question-tp26029591p26095101.html > Sent from the Camel - Users mailing list archive at Nabble.com. > > -- Claus Ibsen Apache Camel Committer Author of Camel in Action: http://www.manning.com/ibsen/ Open Source Integration: http://fusesource.com Blog: http://davsclaus.blogspot.com/ Twitter: http://twitter.com/davsclaus |
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Re: beginner question
by Paul Phillips
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That pointed me in the right direction. Here's a working line of code:
String interestingText = new XPathExpression("//book[author='Neal Stephenson']/title/text()").evaluate(exchange, String.class); XPathExpression was the class I couldn't find :) Thanks!
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Re: beginner question
by Claus Ibsen-2
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On Wed, Oct 28, 2009 at 3:29 PM, Paul Phillips <djphillyp@...> wrote:
> > That pointed me in the right direction. Here's a working line of code: > > String interestingText = new XPathExpression("//book[author='Neal > Stephenson']/title/text()").evaluate(exchange, String.class); > > XPathExpression was the class I couldn't find :) > Cool. I am frankly surprised there isnt any easy to use library that can make the bloddy SUN API a breeze to use. Nobody wants to write 10 lines of xpath factory etc. code to just grab a piece from a XML document. Anyone know of any? Unfortunately the Camel one is currently a bit to tightly coupled with Exchange. We may loosen that in the future and let you evaluate any kind of object so we can provide a nicer helper for you to use. > Thanks! > > > > Claus Ibsen-2 wrote: >> >> On Wed, Oct 28, 2009 at 2:58 PM, Paul Phillips <djphillyp@...> >> wrote: >>> >>> Ok great. >>> >>> From this I've now realised that what I really want to do is grab a bunch >>> of >>> stuff from the incoming xml and store it as properties on the message for >>> future use in the route and then I don't really need the original xml >>> anymore. >>> >>> Now I could write some code like this: >>> >>> DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance(); >>> domFactory.setNamespaceAware(true); // never forget this! >>> DocumentBuilder builder = domFactory.newDocumentBuilder(); >>> Document doc = builder.parse(theIncomingXML); >>> >>> XPathFactory factory = XPathFactory.newInstance(); >>> XPath xpath = factory.newXPath(); >>> XPathExpression expr >>> = xpath.compile("//book[author='Neal Stephenson']/title/text()"); >>> >>> Object result = expr.evaluate(doc, XPathConstants.NODESET); >>> >>> and store the result objects as properties on the message. >>> >>> Is there an "easier" way to do this with Camel? If I am in a class that >>> implements Processor, in the process method, can I access the xpath >>> "helper" >>> stuff that camel provides so that I can just (almost) say >>> >>> String interestingText = message.xpath("//book[author='Neal >>> Stephenson']/title/text()") >>> >>> and it'll handle the parsing etc for me? >> >> Yeah as you work in a Processor where you have the Exchange object handy >> >> Something like this. You may need to tweak it a bit. >> >> String interestingText = xpath("//book[author='Neal >> Stephenson']/title/text()").evaluate(exchange, String.class); >> >> >> >>> >>> >>> >>> >>> >>> >>> James.Strachan wrote: >>>> >>>> 2009/10/23 Paul Phillips <djphillyp@...>: >>>>> >>>>> Hi there >>>>> >>>>> bit of a beginner question here. >>>>> >>>>> I have a situation where I want to >>>>> >>>>> - get some xml from a jms queue >>>>> - send an id contained in the xml to a custom component i have written >>>>> (the >>>>> body of the request should be a string that looks like this: "ID=blah", >>>>> so I >>>>> use a bean to grab the id using xpath and change the body of the >>>>> exchange) >>>>> - this will return a message with a body that looks like "MATCHED=TRUE" >>>>> or >>>>> something >>>>> - if MATCHED=TRUE then I want to send some xml to a different endpoint. >>>> >>>> BTW you can do the above like this... >>>> >>>> public class MyBean { >>>> >>>> @Consume(uri="activemq:SomeQueue") >>>> pubilc void onXml(@XPath("/foo/ID") String myID, Document restOfBody) >>>> { >>>> // return the transformed payload >>>> return "MATCHED=TRUE" >>>> } >>>> } >>>> >>>> Notice Camel can do the XPath for you and inject the ID parameter to >>>> your transformer method (myID) - also notice the lack of any >>>> middleware APIs etc. >>>> >>>> for more details see >>>> http://camel.apache.org/pojo-consuming.html >>>> >>>> -- >>>> James >>>> ------- >>>> http://macstrac.blogspot.com/ >>>> >>>> Open Source Integration >>>> http://fusesource.com/ >>>> >>>> >>> >>> -- >>> View this message in context: >>> http://www.nabble.com/beginner-question-tp26029591p26095101.html >>> Sent from the Camel - Users mailing list archive at Nabble.com. >>> >>> >> >> >> >> -- >> Claus Ibsen >> Apache Camel Committer >> >> Author of Camel in Action: http://www.manning.com/ibsen/ >> Open Source Integration: http://fusesource.com >> Blog: http://davsclaus.blogspot.com/ >> Twitter: http://twitter.com/davsclaus >> >> > > -- > View this message in context: http://www.nabble.com/beginner-question-tp26029591p26095588.html > Sent from the Camel - Users mailing list archive at Nabble.com. > > -- Claus Ibsen Apache Camel Committer Author of Camel in Action: http://www.manning.com/ibsen/ Open Source Integration: http://fusesource.com Blog: http://davsclaus.blogspot.com/ Twitter: http://twitter.com/davsclaus |
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