raboof/pekko
1
0
Fork 0
Code Issues Pull requests Projects Releases 6 Packages Wiki Activity Actions 10

=doc #3689 Make activator templates for camel samples

Browse source 
* @rkuhn found the problems in the scala camel samples
  - HttpSample returns scrambled data
  - CustomRouteSample times out
This commit is contained in:
Patrik Nordwall 2013-11-15 16:28:14 +01:00
parent 362074177a
commit 23dd957ba2
47 changed files with 693 additions and 559 deletions
Download patch file Download diff file Expand all files Collapse all files

163
akka-samples/akka-sample-camel-java/tutorial/index.html Normal file
View file

@ -0,0 +1,163 @@
<!-- <html> -->
<head>
<title>Akka Camel Samples with Java</title>
</head>
<body>
<div>
<p>
This tutorial contains 3 samples of
<a href="http://doc.akka.io/docs/akka/2.3-SNAPSHOT/java/camel.html" target="_blank">Akka Camel</a>.
</p>
<ul>
<li>Asynchronous routing and transformation</li>
<li>Custom Camel route</li>
<li>Quartz scheduler</li>
</ul>
</div>
<div>
<h2>Asynchronous routing and transformation</h2>
<p>
This example demonstrates how to implement consumer and producer actors that
support
<a href="http://doc.akka.io/docs/akka/2.3-SNAPSHOT/java/camel.html#Asynchronous_routing" target="_blank">
Asynchronous routing</a> with their Camel endpoints. The sample
application transforms the content of the Akka homepage, <a href="http://akka.io" target="_blank">http://akka.io</a>,
by replacing every occurrence of *Akka* with *AKKA*.
</p>
<p>
To run this example, go to the <a href="#run" class="shortcut">Run</a>
tab, and start the application main class <code>sample.camel.http.HttpExample</code> if it's not already started.
Then direct the browser to <a href="http://localhost:8875" target="_blank">http://localhost:8875</a> and the
transformed Akka homepage should be displayed. Please note that this example will probably not work if you're
behind an HTTP proxy.
</p>
<p>
The following figure gives an overview how the example actors interact with
external systems and with each other. A browser sends a GET request to
http://localhost:8875 which is the published endpoint of the
<a href="#code/src/main/java/sample/camel/http/HttpConsumer.java" class="shortcut">HttpConsumer</a>
actor. The <code>HttpConsumer</code>actor forwards the requests to the
<a href="#code/src/main/java/sample/camel/http/HttpProducer.java" class="shortcut">HttpProducer.java</a>
actor which retrieves the Akka homepage from http://akka.io. The retrieved HTML
is then forwarded to the
<a href="#code/src/main/java/sample/camel/http/HttpTransformer.java" class="shortcut">HttpTransformer.java</a>
actor which replaces all occurrences of *Akka* with *AKKA*. The transformation result is sent back the HttpConsumer
which finally returns it to the browser.
</p>
<img src="tutorial/camel-async-interact.png" width="400" />
<p>
Implementing the example actor classes and wiring them together is rather easy
as shown in <a href="#code/src/main/java/sample/camel/http/HttpConsumer.java" class="shortcut">HttpConsumer.java</a>,
<a href="#code/src/main/java/sample/camel/http/HttpProducer.java" class="shortcut">HttpProducer.java</a> and
<a href="#code/src/main/java/sample/camel/http/HttpTransformer.java" class="shortcut">HttpTransformer.java</a>.
</p>
<p>
The <a href="http://camel.apache.org/jetty.html" target="_blank">jetty endpoints</a> of HttpConsumer and
HttpProducer support asynchronous in-out message exchanges and do not allocate threads for the full duration of
the exchange. This is achieved by using <a href="http://wiki.eclipse.org/Jetty/Feature/Continuations" target="_blank">Jetty continuations</a>
on the consumer-side and by using <a href="http://wiki.eclipse.org/Jetty/Tutorial/HttpClient" target="_blank">Jetty's asynchronous HTTP client</a>
on the producer side. The following high-level sequence diagram illustrates that.
</p>
<img src="tutorial/camel-async-sequence.png" width="400" />
</div>
<div>
<h2>Custom Camel route example</h2>
<p>
This section also demonstrates the combined usage of a
<a href="#code/src/main/java/sample/camel/route/RouteProducer.java" class="shortcut">RouteProducer</a> and a
<a href="#code/src/main/java/sample/camel/route/RouteConsumer.java" class="shortcut">RouteConsumer</a>
actor as well as the inclusion of a
<a href="#code/src/main/java/sample/camel/route/CustomRouteSample.java" class="shortcut">custom Camel route</a>.
The following figure gives an overview.
</p>
<img src="tutorial/camel-custom-route.png" width="400" />
<ul>
<li>A consumer actor receives a message from an HTTP client</li>
<li>It forwards the message to another actor that transforms the message (encloses
the original message into hyphens)</li>
<li>The transformer actor forwards the transformed message to a producer actor</li>
<li>The producer actor sends the message to a custom Camel route beginning at the
<code>direct:welcome</code> endpoint</li>
<li>A processor (transformer) in the custom Camel route prepends "Welcome" to the
original message and creates a result message</li>
<li>The producer actor sends the result back to the consumer actor which returns
it to the HTTP client</li>
</ul>
<p>
The producer actor knows where to reply the message to because the consumer and
transformer actors have forwarded the original sender reference as well. The
application configuration and the route starting from direct:welcome are done in the code above.
</p>
<p>
To run this example, go to the <a href="#run" class="shortcut">Run</a>
tab, and start the application main class <code>sample.camel.route.CustomRouteExample</code>
</p>
<p>
POST a message to <code>http://localhost:8877/camel/welcome</code>.
</p>
<pre><code>
curl -H "Content-Type: text/plain" -d "Anke" http://localhost:8877/camel/welcome
</code></pre>
<p>
The response should be:
</p>
<pre><code>
Welcome - Anke -
</code></pre>
</div>
<div>
<h2>Quartz Scheduler Example</h2>
<p>
Here is an example showing how simple it is to implement a cron-style scheduler by
using the Camel Quartz component in Akka.
</p>
<p>
Open <a href="#code/src/main/java/sample/camel/quartz/MyQuartzActor.java" class="shortcut">MyQuartzActor.java</a>.
</p>
<p>
The example creates a "timer" actor which fires a message every 2
seconds.
</p>
<p>
For more information about the Camel Quartz component, see here:
<a href="http://camel.apache.org/quartz.html" target="_blank">http://camel.apache.org/quartz.html</a>
</p>
</div>
</body>
</html>