Threads

Options

The Threads eip supports 10 options, which are listed below.

Name Description Default Type

executorServiceRef

To refer to a custom thread pool or use a thread pool profile (as overlay).

String

poolSize

Sets the core pool size.

Integer

maxPoolSize

Sets the maximum pool size.

Integer

keepAliveTime

Sets the keep alive time for idle threads.

Long

timeUnit

Sets the keep alive time unit. By default SECONDS is used.

Enum values:

  • DAYS

  • HOURS

  • MICROSECONDS

  • MILLISECONDS

  • MINUTES

  • NANOSECONDS

  • SECONDS

TimeUnit

maxQueueSize

Sets the maximum number of tasks in the work queue. Use -1 or Integer.MAX_VALUE for an unbounded queue.

Integer

allowCoreThreadTimeOut

Whether idle core threads are allowed to timeout and therefore can shrink the pool size below the core pool size Is by default false.

Boolean

threadName

Sets the thread name to use.

Threads

String

rejectedPolicy

Sets the handler for tasks which cannot be executed by the thread pool.

Enum values:

  • Abort

  • CallerRuns

  • Discard

  • DiscardOldest

ThreadPoolRejectedPolicy

callerRunsWhenRejected

Whether or not to use as caller runs as fallback when a task is rejected being added to the thread pool (when its full). This is only used as fallback if no rejectedPolicy has been configured, or the thread pool has no configured rejection handler. Is by default true.

true

String

description

Sets the description of this node.

DescriptionDefinition

About rejected tasks

The Threads EIP uses a thread pool which has a worker queue for tasks. When the worker queue gets full, the task is rejected. You can customize how to react upon this using the rejectedPolicy and callerRunsWhenRejected option. The latter is used to easily switch between the two most common and recommended settings. Either let the current caller thread execute the task (i.e. it will become synchronous), but also give time for the thread pool to process its current tasks, without adding more tasks (self throttling). This is the default behavior. If setting callerRunsWhenRejected you use the Abort policy, which means the task is rejected, and a RejectedExecutionException is set on the Exchange, and the Exchange will stop continue being routed, and its UnitOfWork will be regarded as failed.

The other options Discard and DiscardOldest work a bit like Abort, however they do not set any exception on the Exchange, which means the Exchange will not be regarded as failed, but the Exchange will be successful. When using Discard and DiscardOldest then the Exchange will not continue being routed.

Example

The example below will add a Thread pool with a pool size of 5 threads before sending to mock:result.

from("seda:a")
  .threads(5)
  .to("mock:result");

And in XML DSL

<route>
    <from uri="seda:a"/>
    <threads poolSize="5"/>
    <to uri="mock:result"/>
</route>
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