THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
Threading Model
This information applies from Available as of Camel 2.3 onwards
The threading model in Camel is based on leveraging the JDK concurrency API which provides thread pools, named ExecutorService.
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- several EIP patterns supports using thread pools for concurrency
- SEDA component for asynchronous connectivity
- Threads DSL in the Camel route
- ServicePools ServicePool for pooling services
- And some component provide thread pools by nature such as JMS, Jetty
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What that means is that for example when you use Multicast with parallelProcessing=true enabled, then it would create a thread pool based on the profile above. The rejectedPolicy have four options: Abort, CallerRuns, Discard, DiscardOldest which corresponds to the same four options provided out of the box in the JDK.
You can define as many thread pool profiles as you like. But there must only one default profile. A custom thread pool profile will inherit from the default profile. Which means that any option you do not explicit define will fallback and use the option from the default profile.
You can use -1 in maxQueueSize to indicate a unbounded queue.
In Java DSL you can configure the default thread pool profile from the ExecutorServiceStartegy which you access from CamelContext.
Create custom thread pool
You can also use the <threadPool/> tag in Spring XML to create a specific thread pool (eg ExecutorService). Notice that any options you do not explicit define, will have Camel to use the default thread pool profile as fallback. For example if you omit setting the maxQueueSize then Camel will fallback and use the value from the default thread pool profiles, which by default is 1000.
Management
All the thread pools that Camel creates are managed and thus you can see them in JConsole under the threadpools category.
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Camel provides a pluggable strategy to hook in your own thread pool provider, for example from a WorkManager in a J2EE server etc.
See the org.apache.camel.spi.ExecutorServiceStrategy interface which you should implement and hook into the WorkManager.
See [Advanced XXX config}} Advanced configuration of CamelContext using Spring for how to configure it.
You can configure it on the CamelContext from Java DSL using the getter/setter.
Component developers
If you develop your own Camel component and are in need of a thread pool, then its advised to use the ExecutorServiceStrategy to create the thread pool you need.
Shutdown
All thread pools created by Camel will be properly shutdown when CamelContext shutdowns which ensures no leaks in the pools in case you run in a server environment with hot deployments and the likes.