[Camel-users] Usage of Camel cache component (Camel component auto discovery)

Hi guys,

I’ve looked through many Camel sources (Camel in Action, Camel documentation
for components on the net) but did not manage to solve the following
problem.

I'm trying to deploy a route which uses the camel-cache component, however,
I'm getting the well-known org.apache.camel.ResolveEndpointFailedException:
Failed to resolve endpoint: cache://test due to: No component found with
scheme: cache.
I'm deploying an OSGi bundle containing the route definition to an Equinox
OSGi container. Here is how my route definition looks like:

<camelContext autoStartup="true"
xmlns="http://camel.apache.org/schema/spring">
  <route>
   <from uri="vm://channelName"/>
   <setHeader headerName="CamelCacheOperation">
    <simple>CamelCacheAdd</simple>
   </setHeader>
   <setHeader headerName="CamelCacheKey">
    <simple>ShindovCache</simple>
   </setHeader>
   <to uri="cache://test" />
  </route>
</camelContext>

As I don't have the Ehcache library (ehcache.jar) that is required by
camel-cache as an OSGi bundle, I have added the library to a directory
called “lib” within the camel-cache bundle and modified its manifest by
adding the following instruction:
Bundle-ClassPath: .,lib/ehcache.jar.

Please note that the camel-cache component bundle gets activated
successfully and exposes the following services:
"Registered Services"
   {org.apache.camel.spi.ComponentResolver}={component=[cache],
service.id=961}
   {org.apache.camel.spi.TypeConverterLoader}={service.id=962}

To me, it looks like the camel-cache component is working properly as it
exposes the ComponentResolver service with filter component=[cache] (Camel
component auto discovery feature?).
Is it possible that the camel-cache bundle is not operating properly and
because of this I'm getting "No component found with scheme: cache"?

If we can assume that everything is OK with the camel-cache component, then
it must be something wrong in the way I’m using the cache component. Do I
need to configure and add this component explicitly to a camel context, or I
can rely on Camel’s component auto discovery?

I tried to define a bean of type CacheComponent with id="cache2" and used
this id in the uri. As a result, I got the following:
Caused by: java.lang.IllegalArgumentException: Unrecognized Cache protocol:
cache2 for uri: cache2://TestCache1
      at
org.apache.camel.component.cache.CacheConfiguration.parseURI(CacheConfiguration.java:62)

When I cerate routes with JMS based endpoints for example, I first define a
bean of type JmsComponent (<bean id=”jmsBean”
class=”org.apache.camel.components.jms.JmsComponent”) and then specify
“jmsBean:topic:topicName” as an uri. Should I use the same approach when
dealing with cache endpoints? If so, this is a bit confusing for me and
rises the following questions:
- If I want to define from/to endpoints with a non-default camel component,
when do I need to explicitly create a bean of the desired component type and
when can I simply type from(“component:name?options”)?
- What’s the point of having camel-jms exposing a
org.apache.camel.spi.ComponentResolver}={component=[jms] service, when I
always need to create a JMS component bean with a connection factory
injected before using “jms:topic:…”?

Thanks in advance for the assistance.

Best regards,
Atanas