8.15. Sampling

Sampling Throttler

A sampling throttler allows you to extract a sample of exchanges from the traffic through a route. It is configured with a sampling period during which only a single exchange is allowed to pass through. All other exchanges will be stopped.
By default, the sample period is 1 second.

Java DSL example

Use the sample() DSL command to invoke the sampler as follows:
// Sample with default sampling period (1 second)
from("direct:sample")
    .sample()
    .to("mock:result");

// Sample with explicitly specified sample period
from("direct:sample-configured")
    .sample(1, TimeUnit.SECONDS)
    .to("mock:result");

// Alternative syntax for specifying sampling period
from("direct:sample-configured-via-dsl")
    .sample().samplePeriod(1).timeUnits(TimeUnit.SECONDS)
    .to("mock:result");

from("direct:sample-messageFrequency")
    .sample(10)
    .to("mock:result");

from("direct:sample-messageFrequency-via-dsl")
    .sample().sampleMessageFrequency(5)
    .to("mock:result");

Spring XML example

In Spring XML, use the sample element to invoke the sampler, where you have the option of specifying the sampling period using the samplePeriod and units attributes:
<route>
    <from uri="direct:sample"/>
    <sample samplePeriod="1" units="seconds">
        <to uri="mock:result"/>
    </sample>
</route>
<route>
    <from uri="direct:sample-messageFrequency"/>
    <sample messageFrequency="10">
        <to uri="mock:result"/>
    </sample>
</route>
<route>
    <from uri="direct:sample-messageFrequency-via-dsl"/>
    <sample messageFrequency="5">
        <to uri="mock:result"/>
    </sample>
</route>

Options

The sample DSL command supports the following options:
Name Default Value Description
messageFrequency Samples the message every N'th message. You can only use either frequency or period.
samplePeriod 1 Samples the message every N'th period. You can only use either frequency or period.
units SECOND Time unit as an enum of java.util.concurrent.TimeUnit from the JDK.