THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
Velocity
The velocity: component allows you to process a message using an Apache Velocity template. This can be ideal when using Templating to generate responses for requests.
Maven users will need to add the following dependency to their pom.xml for this component:
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h2. Velocity The *velocity:* component allows you to process a message using an [Apache Velocity|http://velocity.apache.org/] template. This can be ideal when using [Templating] to generate responses for requests. Maven users will need to add the following dependency to their {{pom.xml}} for this component: {code:xml} <dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-velocity</artifactId> <version>x.x.x</version> <!-- use the same version as your Camel core version --> </dependency> {code} h3. URI format {code} |
URI format
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velocity:templateName[?options]
{code}
Where *templateName* is the |
Where templateName is the classpath-local
...
URI
...
of
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the
...
template
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to
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invoke;
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or
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the
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complete
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URL
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of
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the
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remote
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template
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(eg:
...
...
You
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can
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append
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query
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options
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to
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the
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URI
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in
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the
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following
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format,
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?option=value&option=value&...
Options
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}} h3. Options {div:class=confluenceTableSmall} || Option || Default || Description || | {{loaderCache}} | {{true}} | Velocity based file loader cache. | | {{contentCache}} | {{true}} | Cache for the resource content when it is loaded. \\ Note : as of Camel 2.9 cached resource content can be cleared via JMX using the endpoint's {{clearContentCache}} operation. | | {{encoding}} | {{null}} | Character encoding of the resource content. | | {{propertiesFile}} | {{null}} | New option in Camel 2.1: The URI of the properties file which is used for VelocityEngine initialization. | {div} h3. |
Message
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Headers
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The
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velocity
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component
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sets
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a
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couple
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headers
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on
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the
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message
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(you
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can't
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set
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these
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yourself
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and
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from
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Camel
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2.1
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velocity
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component
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will
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not
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set
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these
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headers
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which
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will
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cause
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some
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side
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effect
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on
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the
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dynamic
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template
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support):
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{div:class=confluenceTableSmall} || Header || Description || | {{CamelVelocityResourceUri}} | The *templateName* as a {{String}} object. | {div} |
Headers
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set
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during
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the
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Velocity
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evaluation
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are
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returned
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to
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the
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message
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and
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added
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as
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headers.
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Then
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its
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kinda
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possible
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to
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return
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values
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from
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Velocity
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to
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the
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Message.
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For
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example,
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to
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set
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the
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header
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value
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of
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fruit
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in
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the
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Velocity
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template
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.tm
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:
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} $in.setHeader('fruit', 'Apple') {code} The {{fruit}} header is now accessible from the {{ |
The fruit header is now accessible from the message.out.headers.
Velocity Context
Camel will provide exchange information in the Velocity context (just a Map). The Exchange is transfered as:
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}}. h3. Velocity Context Camel will provide exchange information in the Velocity context (just a {{Map}}). The {{Exchange}} is transfered as: {div:class=confluenceTableSmall} || key || value || | {{exchange}} | The {{Exchange}} itself. | | {{exchange.properties}} | The {{Exchange}} properties. | | {{headers}} | The headers of the In message. | | {{camelContext}} | The Camel Context intance. | | {{request}} | The In message. | | {{in}} | The In message. | | {{body}} | The In message body. | | {{out}} | The Out message (only for InOut message exchange pattern). | | {{response}} | The Out message (only for InOut message exchange pattern). | {div} h3. |
Hot
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reloading
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The
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Velocity
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template
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resource
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is,
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by
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default,
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hot
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reloadable
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for
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both
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file
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and
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classpath
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resources
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(expanded
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jar).
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If
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you
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set
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contentCache=true
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,
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Camel
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will
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only
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load
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the
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resource
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once,
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and
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thus
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hot
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reloading
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is
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not
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possible.
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This
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scenario
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can
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be
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used
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in
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production,
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when
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the
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resource
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never
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changes.
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Dynamic
...
templates
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Available
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as
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of
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Camel
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2.1
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Camel
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provides
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two
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headers
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by
...
which
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you
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can
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define
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a
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different
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resource
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location
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for
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a
...
template
...
or
...
the
...
template
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content
...
itself.
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If
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any
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of
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these
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headers
...
is
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set
...
then
...
Camel
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uses
...
this
...
over
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the
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endpoint
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configured
...
resource.
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This
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allows
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you
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to
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provide
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a
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dynamic
...
template
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at
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runtime.
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{div:class=confluenceTableSmall} || Header || Type || Description || | CamelVelocityResourceUri | String | *Camel 2.1:* A URI for the template resource to use instead of the endpoint configured. | | CamelVelocityTemplate | String | *Camel 2.1:* The template to use instead of the endpoint configured. | {div} h3. Samples For example you could use something like {code} |
Samples
For example you could use something like
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from("activemq:My.Queue").
to("velocity:com/acme/MyResponse.vm");
{code}
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To
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use
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a
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Velocity
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template
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to
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formulate
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a
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response
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to
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a
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message
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for
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InOut
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message
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exchanges
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(where
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there
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is
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a
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JMSReplyTo
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header).
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If
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you
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want
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to
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use
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InOnly
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and
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consume
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the
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message
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and
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send
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it
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to
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another
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destination,
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you
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could
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use
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the
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following
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route:
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} from("activemq:My.Queue"). to("velocity:com/acme/MyResponse.vm"). to("activemq:Another.Queue"); {code} |
And
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to
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use
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the
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content
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cache,
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e.g.
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for
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use
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in
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production,
...
where
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the
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.vm
...
template
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never
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changes:
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} from("activemq:My.Queue"). to("velocity:com/acme/MyResponse.vm?contentCache=true"). to("activemq:Another.Queue"); {code} |
And
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a
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file
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based
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resource:
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} from("activemq:My.Queue"). to("velocity:file://myfolder/MyResponse.vm?contentCache=true"). to("activemq:Another.Queue"); {code} In *Camel |
In Camel 2.1
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it's
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possible
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to
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specify
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what
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template
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the
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component
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should
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use
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dynamically
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via
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a
...
header,
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so
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for
...
example:
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} from("direct:in"). setHeader("CamelVelocityResourceUri").constant("path/to/my/template.vm"). to("velocity:dummy"); {code} In *Camel |
In Camel 2.1
...
it's
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possible
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to
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specify
...
a
...
template
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directly
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as
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a
...
header
...
the
...
component
...
should
...
use
...
dynamically
...
via
...
a
...
header,
...
so
...
for
...
example:
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} from("direct:in"). setHeader("CamelVelocityTemplate").constant("Hi this is a velocity template that can do templating ${body}"). to("velocity:dummy"); {code} h3. The Email Sample In this sample we want to use Velocity templating for an order confirmation email. The email template is laid out in Velocity as: {code |
The Email Sample
In this sample we want to use Velocity templating for an order confirmation email. The email template is laid out in Velocity as:
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} Dear ${headers.lastName}, ${headers.firstName} Thanks for the order of ${headers.item}. Regards Camel Riders Bookstore ${body} {code} |
And
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the
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java
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code:
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{snippet:id=e1|lang=java|url=camel/trunk/components/camel-velocity/src/test/java/org/apache/camel/component/velocity/VelocityLetterTest.java} {include:Endpoint See Also} |
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