THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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Available as of Camel 2.15.0
org.apache.camel/camel-scr bundle provides a base class, AbstractCamelRunner, which manages a Camel context for you and a helper class, ScrHelper, for using your SCR properties in unit tests. Camel-scr feature for Apache Karaf defines all features and bundles required for running Camel in SCR bundles.
AbstractCamelRunner class ties CamelContext's lifecycle to Service Component's lifecycle and handles configuration with help of Camel's PropertiesComponent. All you have to do to make a Service Component out of your java class is to extend it from AbstractCamelRunner and add the following org.apache.felix.scr.annotations on class level:
| Code Block | ||
|---|---|---|
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@Component
@References({
@Reference(name = "camelComponent",referenceInterface = ComponentResolver.class,
cardinality = ReferenceCardinality.MANDATORY_MULTIPLE, policy = ReferencePolicy.DYNAMIC,
policyOption = ReferencePolicyOption.GREEDY, bind = "gotCamelComponent", unbind = "lostCamelComponent")
}) |
Then implement getRouteBuilders() method which returns the Camel routes you want to run. And finally provide the default configuration with:
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That's all. And if you used camel-archetype-scr to generate a project all this is already taken care of.
CamelContextId and active properties control the CamelContext's name (defaults to "camel-runner-default") and whether it will be started or not (defaults to "false"), respectively. In addition to these you can add and use as many properties as you like. Camel's PropertiesComponent handles recursive properties and prefixing with fallback without problem.
AbstractCamelRunner will make these properties available to your RouteBuilders through Camel's PropertiesComponent and it will also inject these values into your Service Component's and RouteBuilder's fields when their names match. The fields can be declared with any visibility level, and many types are supported (String, int, boolean, URL, ...).
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- When component's configuration policy and mandatory references are satisfied SCR calls
activate(). This creates and sets up a CamelContext through the following call chain:activate()=> →prepare()-> →createCamelContext()-> →setupPropertiesComponent()-> →configure()-> →setupCamelContext(). Finally, the context is scheduled to start after a delay defined inAbstractCamelRunner.START_DELAYwithrunWithDelay(). - When Camel components (
ComponentResolverservices, to be exact) are registered in OSGi, SCR callsgotCamelComponent()which reschedules/delays the CamelContext start further by the sameAbstractCamelRunner.START_DELAY. This in effect makes CamelContext wait until all Camel components are loaded or there is a sufficient gap between them. The same logic will tell a failed-to-start CamelContext to try again whenever we add more Camel components. - When Camel components are unregistered SCR calls
lostCamelComponent(). This call does nothing. - When one of the requirements that caused the call to
activate()is lost SCR will calldeactivate(). This will shutdown the CamelContext.
In (non-OSGi) unit tests you should use prepare() -> → run() -> → stop() instead of activate() -> → deactivate() for more fine-grained control. Also, this allows us to avoid possible SCR specific operations in tests.
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The easiest way to create an Camel SCR bundle is to use camel-archetype-scr Maven archetype.
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mvn
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archetype:generate
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-Dfilter=org.apache.camel.archetypes:camel-archetype-scr
Choose
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archetype:
1:
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local
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->
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org.apache.camel.archetypes:camel-archetype-scr
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(Creates
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a
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new
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Camel
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SCR
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bundle
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project
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for
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Karaf)
Choose
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a
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number
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or
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apply
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filter
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(format:
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[groupId:]artifactId,
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case
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sensitive
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contains):
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:
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1
Define
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value
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for
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property
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'groupId':
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:
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my.example
[INFO]
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Using
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property:
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groupId
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=
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my.example
Define
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value
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for
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property
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'artifactId':
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:
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my-test
Define
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value
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for
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property
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'version':
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1.0-SNAPSHOT:
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:
Define
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value
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for
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property
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'package':
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my.example:
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:
[INFO]
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Using
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property:
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archetypeArtifactId
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=
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camel-archetype-scr
[INFO]
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Using
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property:
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archetypeGroupId
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=
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org.apache.camel.archetypes
[INFO]
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Using
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property:
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archetypeVersion
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=
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2.15-SNAPSHOT
Define
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value
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for
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property
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'className':
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:
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MyTest
Confirm
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properties
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configuration:
groupId:
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my.example
artifactId:
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my-test
version:
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1.0-SNAPSHOT
package:
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my.example
archetypeArtifactId:
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camel-archetype-scr
archetypeGroupId:
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org.apache.camel.archetypes
archetypeVersion:
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2.15-SNAPSHOT
className:
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MyTest
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Y:
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:
All done! Check ReadMe.txt in the generated project folder for the next steps.
To deploy a Camel SCR bundle project in Apache Karaf:
On Karaf command line:
#
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Add
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Camel
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feature
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repository
features:chooseurl
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camel
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2.15-SNAPSHOT
#
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Install
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camel-scr
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feature
features:install
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camel-scr
# Install commons-lang, used in the example route to validate parameters
osgi:install mvn:commons-lang/commons-lang/2.6
# Install and start your bundle
osgi:install -s mvn:your.company/your-bundle/version
#
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See
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how
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it's
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running
log:tail
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-n
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10
Press ctrl-c to stop watching the log.