comparing two XML files

[Stephen Cameron <st...@gmail.com>]

Hi,

I want to do a data processing task, that involves comparing the contents
of two XML files. This is simply to match the equivalent record in the
second for every record in the first, make a decision by comparing these
matches, then generate a third file with the actions messages based on the
the comparison result.

If there is no match made that is another message type that needs to be
created.

I procedural code this is a inner and outer loop kind of situation. How can
I set up the same thing in Camel. Or, should I write some custom code to do
it?

Thanks for your advice, or pointing me in a good direction.

Steve Cameron

AW: comparing two XML files

["Jan Matèrne (jhm)" <ap...@materne.de>]

> It is simply a comparison of values in the files not of the structure
> of the files. 

If you could compare via xpath then you could write that directly in Camel:

from("direct:in")
    .switch()
        .when(xpath(...)).to(...)


> Now I want to pull in some more data to the route to
> allow me to decide what needs to pass on to the next Processor in the
> chain.

sounds like EIP "content enricher"
http://camel.apache.org/content-enricher.html



> Actually, I think I should read the Enterprise Integration Patterns book. 

always good ;)



Jan

Re: comparing two XML files

[Stephen Cameron <st...@gmail.com>]

Hi,

Thanks for your kind advice. But I have not explained the problem well
enough.

It is simply a comparison of values in the files not of the structure of
the files. A route seems a linear processing thing to my simple
understanding. Now I want to pull in some more data to the route to allow
me to decide what needs to pass on to the next Processor in the chain.

So I guess its both a transformation & a conditional splitting kind of
situation. I can write a custom Processor to do this. I just wondered if
there was an alternative Camel way to do it. Actually, I think I should
read the Enterprise Integration Patterns book. After a bit more reading it
is clear that I cannot get away with just asking for advice.

Thanks again.


On Mon, May 5, 2014 at 4:12 PM, Jan Matèrne (jhm) <ap...@materne.de> wrote:

> For comparing XML I would google or have a look at XMLUnit [1].
>
> AFAI understand Camel it reacts on one message. But you want to compare
> two files.
> So the message could contain the content of both files.
>
> from("direct:in")
>     .bean(MyXmlDiff.class, "compare(${headers.XML_ONE},
> ${headers.XML_TWO}")
>     .to("velocity:...")
>     .to("direct:out")
>
> I assume that the content of both files is available via the two message
> headers XML_ONE and XML_TWO.
>
> I use bean binding [3] for invoking my custom bean.
> That uses XMLUnit for just doing the comparison
>    public class MyXmlDiff {
>        public String compare(String xml1, String xml2) {
>            StringBuilder rv = new StringBuilder;
>            Diff xmlunitDiff = new Diff(xml1, xml2);
>            if (xmlunitDiff.similar()) {
>                // use XMLUnit classes for getting the diffs and add
>                // them to this return value.
>                rv.add(...);
>            }
>            // The return value of this method is the body
>            // of the next Camel step.
>            return rv.toSting();
>        }
>    }
>
> Then use a template language for generating the final artifact.
>
>
> Because I am not sure if headers are copied via the bean binding, maybe
> use message properties instead.
>
>
> Jan
>
>
> [1] http://xmlunit.sourceforge.net/
> [2] https://camel.apache.org/bean-binding.html
>
>
>
>
> > -----Ursprüngliche Nachricht-----
> > Von: Stephen Cameron [mailto:steve.cameron.62@gmail.com]
> > Gesendet: Montag, 5. Mai 2014 05:59
> > An: users@camel.apache.org
> > Betreff: comparing two XML files
> >
> > Hi,
> >
> > I want to do a data processing task, that involves comparing the
> > contents of two XML files. This is simply to match the equivalent
> > record in the second for every record in the first, make a decision by
> > comparing these matches, then generate a third file with the actions
> > messages based on the the comparison result.
> >
> > If there is no match made that is another message type that needs to be
> > created.
> >
> > I procedural code this is a inner and outer loop kind of situation. How
> > can I set up the same thing in Camel. Or, should I write some custom
> > code to do it?
> >
> > Thanks for your advice, or pointing me in a good direction.
> >
> > Steve Cameron
>
>

AW: comparing two XML files

["Jan Matèrne (jhm)" <ap...@materne.de>]

For comparing XML I would google or have a look at XMLUnit [1].

AFAI understand Camel it reacts on one message. But you want to compare two files.
So the message could contain the content of both files.

from("direct:in")
    .bean(MyXmlDiff.class, "compare(${headers.XML_ONE}, ${headers.XML_TWO}")
    .to("velocity:...")
    .to("direct:out")

I assume that the content of both files is available via the two message headers XML_ONE and XML_TWO.

I use bean binding [3] for invoking my custom bean.
That uses XMLUnit for just doing the comparison
   public class MyXmlDiff {
       public String compare(String xml1, String xml2) {
           StringBuilder rv = new StringBuilder;
           Diff xmlunitDiff = new Diff(xml1, xml2);
           if (xmlunitDiff.similar()) {
               // use XMLUnit classes for getting the diffs and add
               // them to this return value.
               rv.add(...);   
           }
           // The return value of this method is the body
           // of the next Camel step.
           return rv.toSting();
       }
   }

Then use a template language for generating the final artifact.


Because I am not sure if headers are copied via the bean binding, maybe use message properties instead.


Jan


[1] http://xmlunit.sourceforge.net/
[2] https://camel.apache.org/bean-binding.html




> -----Ursprüngliche Nachricht-----
> Von: Stephen Cameron [mailto:steve.cameron.62@gmail.com]
> Gesendet: Montag, 5. Mai 2014 05:59
> An: users@camel.apache.org
> Betreff: comparing two XML files
> 
> Hi,
> 
> I want to do a data processing task, that involves comparing the
> contents of two XML files. This is simply to match the equivalent
> record in the second for every record in the first, make a decision by
> comparing these matches, then generate a third file with the actions
> messages based on the the comparison result.
> 
> If there is no match made that is another message type that needs to be
> created.
> 
> I procedural code this is a inner and outer loop kind of situation. How
> can I set up the same thing in Camel. Or, should I write some custom
> code to do it?
> 
> Thanks for your advice, or pointing me in a good direction.
> 
> Steve Cameron