Github user drigodwin commented on a diff in the pull request:
https://github.com/apache/brooklyn-docs/pull/160#discussion_r109779436
--- Diff: guide/java/enrichers.md ---
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+---
+title: Enrichers
+layout: website-normal
+toc: ../guide_toc.json
+categories: [use, guide, defining-applications]
+---
+
+Enrichers provide advanced manipulation of an entity's sensor values.
+
+#### Transformer
+
+- org.apache.brooklyn.enricher.stock.Transformer
+
+Transforms attributes of an entity.
+
+{% highlight yaml %}
+brooklyn.enrichers:
+- type: org.apache.brooklyn.enricher.stock.Transformer
+ brooklyn.config:
+ enricher.sourceSensor: $brooklyn:sensor("urls.tcp.string")
+ enricher.targetSensor: $brooklyn:sensor("urls.tcp.withBrackets")
+ enricher.targetValue: $brooklyn:formatString("[%s]",
$brooklyn:attributeWhenReady("urls.tcp.string"))
+{% endhighlight %}
+
+#### Propagator
+
+- org.apache.brooklyn.enricher.stock.Propagator
+
+Use propagator to duplicate one sensor as another, giving the supplied
sensor mapping.
+The other use of Propagator is where you specify a producer (using
`$brooklyn:entity(...)` as below)
+from which to take sensors; in that mode you can specify `propagate` as a
list of sensors whose names are unchanged,
+instead of (or in addition to) this map
+
+{% highlight yaml %}
+brooklyn.enrichers:
+- type: org.apache.brooklyn.enricher.stock.Propagator
+ brooklyn.config:
+ producer: $brooklyn:entity("cluster")
+- type: org.apache.brooklyn.enricher.stock.Propagator
+ brooklyn.config:
+ sensorMapping:
+ $brooklyn:sensor("url"):
$brooklyn:sensor("org.apache.brooklyn.core.entity.Attributes", "main.uri")
+{% endhighlight %}
+
+#### Custom Aggregating
+
+- org.apache.brooklyn.enricher.stock.Aggregator
+
+Aggregates multiple sensor values (usually across a tier, esp. a cluster)
and performs a supplied aggregation method to them to return an aggregate
figure, e.g. sum, mean, median, etc.
+
+{% highlight yaml %}
+brooklyn.enrichers:
+- type: org.apache.brooklyn.enricher.stock.Aggregator
+ brooklyn.config:
+ enricher.sourceSensor: $brooklyn:sensor("webapp.reqs.perSec.windowed")
+ enricher.targetSensor: $brooklyn:sensor("webapp.reqs.perSec.perNode")
+ enricher.aggregating.fromMembers: true
+ transformation: average
+{% endhighlight %}
+
+#### Joiner
+
+- org.apache.brooklyn.enricher.stock.Joiner
+
+Joins a sensor whose output is a list into a single item joined by a
separator.
+
+{% highlight yaml %}
+brooklyn.enrichers:
+- type: org.apache.brooklyn.enricher.stock.Joiner
+ brooklyn.config:
+ enricher.sourceSensor: $brooklyn:sensor("urls.tcp.list")
+ enricher.targetSensor: $brooklyn:sensor("urls.tcp.string")
+ uniqueTag: urls.quoted.string
+{% endhighlight %}
+
+#### Delta Enricher
+
+- org.apache.brooklyn.policy.enricher.Delta Enricher
+
+Converts absolute sensor values into a delta.
+
+#### Time-weighted Delta
+
+- org.apache.brooklyn.enricher.stock.YamlTimeWeightedDeltaEnricher
+
+Converts absolute sensor values into a delta/second.
+
+{% highlight yaml %}
+brooklyn.enrichers:
+- type: org.apache.brooklyn.enricher.stock.YamlTimeWeightedDeltaEnricher
+ brooklyn.config:
+ enricher.sourceSensor: reqs.count
+ enricher.targetSensor: reqs.per_sec
+ enricher.delta.period: 1s
+{% endhighlight %}
+
+#### Rolling Mean
+
+- org.apache.brooklyn.policy.enricher.RollingMeanEnricher
+
+Converts the last *N* sensor values into a mean.
+
+#### Rolling Time-window Mean
+
+- org.apache.brooklyn.policy.enricher.RollingTimeWindowMeanEnricher
+
+Converts the last *N* seconds of sensor values into a weighted mean.
+
+#### Http Latency Detector
+
+-
org.apache.brooklyn.policy.enricher.RollingTimeWindowMeanEnricher.HttpLatencyDetector
+
+An Enricher which computes latency in accessing a URL.
+
+#### Combiner
+
+- org.apache.brooklyn.enricher.stock.Combiner
+
+Can be used to combine the values of sensors. This enricher should be
instantiated using Enrichers.buider.combining(..).
--- End diff --
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