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The xslt: component allows you to process a message using an XSLT template. This can be ideal when using Templating to generate respopnses for requests.

URI format

Code Block
xslt:templateName[?options]

...

Here are some example URIs

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class	confluenceTableSmall

Wiki Markup

{div:class=confluenceTableSmall} || URI || Description || | {code}

URI

Description

Code Block

xslt:com/acme/mytransform.xsl

{code} | refers to the file

refers to the file com/acme/mytransform.xsl

on

the

classpath | | {code}

classpath

Code Block
xslt:file:///foo/bar.xsl

{code} | refers to the file

refers to the file /foo/bar.xsl

| | {code}

Code Block
xslt:http://acme.com/cheese/foo.xsl

{code} | refers to the remote http resource | {div}

refers to the remote http resource

Maven users will need to add the following dependency to their pom.xml for this component when using Camel 2.8 or older:

Code Block

	xml
	xml


<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-spring</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>

From Camel 2.9 onwards the XSLT component is provided directly in the camel-core.

Options

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class	confluenceTableSmall

Wiki Markup

{div:class=confluenceTableSmall} || Name || Default Value || Description || | {{converter}} | {{null}} | Option to override default [XmlConverter|http://camel.apache.org/maven/current/camel-core/apidocs/org/apache/camel/converter/jaxp/XmlConverter.html]. Will lookup for the converter in the [Registry]. The provided converted must be of type org.apache.camel.converter.jaxp.XmlConverter. | | {{transformerFactory}} | {{null}} | Option to override default [TransformerFactory|http://java.sun.com/j2se/1.5.0/docs/api/javax/xml/transform/TransformerFactory.html]. Will lookup for the transformerFactory in the [Registry]. The provided transformer factory must be of type javax.xml.transform.TransformerFactory. | | {{transformerFactoryClass}} | {{null}} | Option to override default [TransformerFactory|http://java.sun.com/j2se/1.5.0/docs/api/javax/xml/transform/TransformerFactory.html]. Will create a TransformerFactoryClass instance and set it to the converter. | | {{uriResolver}} | {{null}} | *Camel 2.3*: Allows you to use a custom {{javax.xml.transformation.URIResolver}}. Camel will by default use its own implementation {{

Name	Default Value	Description
`converter`	`null`	Option to override default XmlConverter. Will lookup for the converter in the Registry. The provided converted must be of type org.apache.camel.converter.jaxp.XmlConverter.
`transformerFactory`	`null`	Option to override default TransformerFactory. Will lookup for the transformerFactory in the Registry. The provided transformer factory must be of type javax.xml.transform.TransformerFactory.
`transformerFactoryClass`	`null`	Option to override default TransformerFactory. Will create a TransformerFactoryClass instance and set it to the converter.
`uriResolverFactory`	`DefaultXsltUriResolverFactory`	Camel 2.17: Reference to a `org.apache.camel.component.xslt.XsltUriResolverFactory` which creates an URI resolver per endpoint`.`The default implementation returns an instance of `org.apache.camel.component.xslt.DefaultXsltUriResolverFactory` which creates the default URI resolver `org.apache.camel.builder.xml`.XsltUriResolver per endpoint. The default URI resolver reads XSLT documents from the classpath and the file system. This option instead of the option `uriResolver` shall be used when the URI resolver depends on the resource URI of the root XSLT document specified in the endpoint; for example, if you want to extend the default URI resolver. This option is also available on the XSLT component, so that you can set the resource resolver factory only once for all endpoints.
`uriResolver`	`null`	Camel 2.3: Allows you to use a custom `javax.xml.transformation.URIResolver`. Camel will by default use its own implementation

org.apache.camel.builder.xml.XsltUriResolver

}}

which

is

capable

of

loading

from

classpath.

| | {{resultHandlerFactory}} | {{null}} | *Camel


`resultHandlerFactory`	`null`	Camel 2.3:

*

Allows

you

to

use

a

custom

{{

org.apache.camel.builder.xml.ResultHandlerFactory

}}

which

is

capable

of

using

custom

{{

org.apache.camel.builder.xml.ResultHandler

}} types. | | {{failOnNullBody}} | {{true}} | *Camel

types.
`failOnNullBody`	`true`	Camel 2.3:

*

Whether

or

not

to

throw

an

exception

if

the

input

body

is

null.

| | {{deleteOutputFile}} | {{false}} | *Camel 2


`deleteOutputFile`	`false`	Camel 2.6:

*

If

you

have

{{

output=file

}}

then

this

option

dictates

whether

or

not

the

output

file

should

be

deleted

when

the

[

Exchange

]

is

done

processing.

For

example

suppose

the

output

file

is

a

temporary

file,

then

it

can

be

a

good

idea

to

delete

it

after

use.

| | {{output}} | {{string}} | *Camel


`output`	`string`	Camel 2.3:

*

Option

to

specify

which

output

type

to

use.

Possible

values

are:

{{

string,

bytes,

DOM,

file

}}

.

The

first

three

options

are

all

in

memory

based,

where

as

{{

file

}}

is

streamed

directly

to

a

{{

java.io.File

}}

.

For

{{

file

}}

you

*

must

*

specify

the

filename

in

the

IN

header

with

the

key

{{

Exchange.XSLT_FILE_NAME

}}

which

is

also

{{

CamelXsltFileName

}}

.

Also

any

paths

leading

to

the

filename

must

be

created

beforehand,

otherwise

an

exception

is

thrown

at

runtime.

| | {{contentCache}} | {{true}} | *Camel


`contentCache`	`true`	Camel 2.6:

*

Cache

for

the

resource

content

(the

stylesheet

file)

when

it

is

loaded.

If

set

to

{{

false

}}

Camel

will

reload

the

stylesheet

file

on

each

message

processing.

This

is

good

for

development.

Note:

from

*

Camel

2.9

*

a

cached

stylesheet

can

be

forced

to

reload

at

runtime

via

JMX

using

the

{{

clearCachedStylesheet

}}

operation.

| | {{allowStAX}} | {{false}} | *Camel 2.8.


`allowStAX`		Camel 2.8.3/2.9:

*

Whether

to

allow

using

StAX

as

the

{{

javax.xml.transform.Source

}}. | | {{transformerCacheSize}} | {{0}} | *Camel 2.9

. The option is default `false` in Camel 2.11.3/2.12.2 or older. And default `true` in Camel 2.11.4/2.12.3 onwards.
`transformerCacheSize`	`0`	Camel 2.9.3/2.10.1:

*

The

number

of

{{

javax.xml.transform.Transformer

}}

object

that

are

cached

for

reuse

to

avoid

calls

to

{{Template

Template.newTransformer()

}}. | | {{saxon}} | {{false}} | *Camel

.
`saxon`	`false`	Camel 2.11:

*

Whether

to

use

Saxon

as

the

{{

transformerFactoryClass

}}

.

If

enabled

then

the

class

{{

net.sf.saxon.TransformerFactoryImpl

}}

.

You

would

need

to

add

Saxon

to

the

classpath.

| {div}

Using XSLT endpoints

For example you could use something like

Code Block
from("activemq:My.Queue"). to("xslt:com/acme/mytransform.xsl");

To use an XSLT template to formulate a response for a message for InOut message exchanges (where there is a JMSReplyTo header).

If you want to use InOnly and consume the message and send it to another destination you could use the following route:


`saxonExtensionFunctions`	`null`	Camel 2.17: Allows to configure one or more custom net.sf.saxon.lib.ExtensionFunctionDefinition. You would need to add Saxon to the classpath. By setting this option, saxon option will be turned out automatically.
`errorListener`		Camel 2.14: Allows to configure to use a custom `javax.xml.transform.ErrorListener`. Beware when doing this then the default error listener which captures any errors or fatal errors and store information on the Exchange as properties is not in use. So only use this option for special use-cases.
`entityResolver`		Camel 2.18: To use a custom org.xml.sax.EntityResolver with javax.xml.transform.sax.SAXSource.

Using XSLT endpoints

For example you could use something like

Code Block
from("activemq:My.Queue")
Code Block
from("activemq:My.Queue"). to("xslt:com/acme/mytransform.xsl"). to("activemq:Another.Queuexslt:com/acme/mytransform.xsl");

Getting Parameters into the XSLT to work with

By default, all headers are added as parameters which are available in the XSLT.
To do this you will need to declare the parameter so it is then useable.

...


<setHeader headerName="myParam"><constant>42</constant></setHeader>
<to uri="xslt:MyTransform.xsl"/>

To use an XSLT template to formulate a response for a message for InOut message exchanges (where there is a JMSReplyTo header).

If you want to use InOnly and consume the message and send it to another destination you could use the following route:

Code Block
from("activemq:My.Queue"). to("xslt:com/acme/mytransform.xsl"). to("activemq:Another.Queue");

Getting Parameters into the XSLT to work with

By default, all headers are added as parameters which are available in the XSLT.
To do this you will need to declare the parameter so it is then useable.And the XSLT just needs to declare it at the top level for it to be available:

Code Block

	xml
	xml

<setHeader headerName="myParam"><constant>42</constant></setHeader>
<to uri="xslt:MyTransform.xsl"/>

And the XSLT just needs to declare it at the top level for it to be available:

Code Block

	xml
	xml

<xsl: ...
<xsl: ...... >

   <xsl:param name="myParam"/>
  
    <xsl:template ...>

...

To use the above examples in Spring XML you would use something like

Code Block

	xml
	xml


  <camelContext xmlns="http://activemq.apache.org/camel/schema/spring">
    <route>
      <from uri="activemq:My.Queue"/>
      <to uri="xslt:org/apache/camel/spring/processor/example.xsl"/>
      <to uri="activemq:Another.Queue"/>
    </route>
  </camelContext>

...

For example this include:

Code Block

	xml
	xml


<xsl:include href="staff_template.xsl"/>

...

For example this include:

Code Block

	xml
	xml


<xsl:include href="staff_template.xsl"/>

Will now be located relative from the starting endpoint, which for example could be:

Code Block
.to("xslt:org/apache/camel/component/xslt/staff_include_relative.xsl")

...

You can also refer back in the paths such as

Code Block
<xsl:include href="../staff_other_template.xsl"/>

...

When using xsl:include such as:

Code Block

	xml
	xml


<xsl:include href="staff_template.xsl"/>

Then in Camel 2.10.3 and older, then Camel will use "classpath:" as the default prefix, and load the resource from the classpath. This works for most cases, but if you configure the starting resource to load from file,

Code Block
.to("xslt:file:etc/xslt/staff_include_relative.xsl")

.. then you would have to prefix all your includes with "file:" as well.

Code Block

	xml
	xml


<xsl:include href="file:staff_template.xsl"/>

From Camel 2.10.4 onwards we have made this easier as Camel will use the prefix from the endpoint configuration as the default prefix. So from Camel 2.10.4 onwards you can do:

Code Block

	xml
	xml


<xsl:include href="staff_template.xsl"/>

Which will load the staff_template.xsl resource from the file system, as the endpoint was configured with "file:" as prefix.
You can still though explicit configure a prefix, and then mix and match. And have both file and classpath loading. But that would be unusual, as most people either use file or classpath based resources.

Dynamic stylesheets

Using Saxon extension functions

Since Saxon 9.2, writing extension functions has been supplemented by a new mechanism, referred to as integrated extension functions you can now easily use camel:

- Java example:

Code Block

language	java

SimpleRegistry registry = new SimpleRegistry();
registry.put("function1", new MyExtensionFunction1());
registry.put("function2", new MyExtensionFunction2());

CamelContext context = new DefaultCamelContext(registry);
context.addRoutes(new RouteBuilder() {
    @Override
    public void configure() throws Exception {
        from("direct:start")
            .to("xslt:org/apache/camel/component/xslt/extensions/extensions.xslt?saxonExtensionFunctions=#function1,#function2");
    }
});

Spring example:

Code Block

language	xml

<camelContext xmlns="http://camel.apache.org/schema/spring">
  <route>
    <from uri="direct:extensions"/>
    <to uri="xslt:org/apache/camel/component/xslt/extensions/extensions.xslt?saxonExtensionFunctions=#function1,#function2"/>
  </route>
</camelContext>


<bean id="function1" class="org.apache.camel.component.xslt.extensions.MyExtensionFunction1"/>
<bean id="function2" class="org.apache.camel.component.xslt.extensions.MyExtensionFunction2"/>

Dynamic stylesheets

To provide a dynamic stylesheet at runtime you can define a dynamic URI. See How to use a dynamic URI in to() for more information.

Available as of Camel 2.9 (removed in 2.11.4, 2.12.3 and 2.13.0)
Camel provides the CamelXsltResourceUri header which you can use to define a stylesheet to use instead of what is configured on the endpoint URI. This allows you to provide a dynamic stylesheet at runtime.

Accessing warnings, errors and fatalErrors from XSLT ErrorListener

Available as of Camel 2.14

From Camel 2.14 onwards, any warning/error or fatalError is stored on the current Exchange as a property with the keys Exchange.XSLT_ERROR, Exchange.XSLT_FATAL_ERROR, or Exchange.XSLT_WARNING which allows end users to get hold of any errors happening during transformation.

For example in the stylesheet below, we want to terminate if a staff has an empty dob field. And to include a custom error message using xsl:message.

Code Block

  <xsl:template match="/">
    <html>
      <body>
        <xsl:for-each select="staff/programmer">
          <p>Name: <xsl:value-of select="name"/><br />
            <xsl:if test="dob=''">
              <xsl:message terminate="yes">Error: DOB is an empty string!</xsl:message>
            </xsl:if>
          </p>
        </xsl:for-each>
      </body>
    </html>
  </xsl:template>

This information is not available on the Exchange stored as an Exception that contains the message in the getMessage() method on the exception. The exception is stored on the Exchange as a warning with the key Exchange.XSLT_WARNINGAvailable as of Camel 2.9
Camel provides the CamelXsltResourceUri header which you can use to define a stylesheet to use instead of what is configured on the endpoint URI. This allows you to provide a dynamic stylesheet at runtime.

Notes on using XSLT and Java Versions

...

In case anybody faces issues with the XSLT endpoint please review these points.
I was trying to use an xslt endpoint for a simple transformation from one xml to another using a simple xsl. The output xml kept appearing (after the xslt processor in the route) with outermost xml tag with no content within.
No explanations show up in the DEBUG logs. On the TRACE logs however I did find some error/warning indicating that the XMLConverter bean could no be initialized.
After a few hours of cranking my mind, I had to do the following to get it to work (thanks to some posts on the users forum that gave some clue):
1. Use the transformerFactory option in the route ("xslt:my-transformer.xsl?transformerFactory=tFactory") with the tFactory bean having bean defined in the spring context for class="org.apache.xalan.xsltc.trax.TransformerFactoryImpl".
2. Added the Xalan jar into my maven pom.
My guess is that the default xml parsing mechanism supplied within the JDK (I am using 1.6.0_03) does not work right in this context and does not throw up any error either. When I switched to Xalan this way it works. This is not a Camel issue, but might need a mention on the xslt component page.
Another note, jdk 1.6.0_03 ships with JAXB 2.0 while Camel needs 2.1. One workaround is to add the 2.1 jar to the jre/lib/endorsed directory for the jvm or as specified by the container.
Hope this post saves newbie Camel riders some time.

Include Page

	Endpoint See Also
	Endpoint See Also

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Versions Compared

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Key

URI format

Options

Using XSLT endpoints

Using XSLT endpoints

Getting Parameters into the XSLT to work with

Getting Parameters into the XSLT to work with

Dynamic stylesheets

Using Saxon extension functions

Dynamic stylesheets

Accessing warnings, errors and fatalErrors from XSLT ErrorListener

Notes on using XSLT and Java Versions