Spring/spring-integration
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

INT-1516 added docs for <router> expression, mentinoing projection/selection

Browse Source
This commit is contained in:
Oleg Zhurakousky
2010-11-12 08:11:55 -05:00
parent 063845ed79
commit ebd06fc2d4
2 changed files with 29 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
docs/src/reference/docbook/router.xml
View File

@@ -150,7 +150,7 @@
</section>
<section id="router-namespace">
<title>The &lt;router&gt; element</title>
<title>Namespace support for Router - &lt;router&gt; element</title>
<para>
The "router" element provides a simple way to connect a router to an input channel, and also accepts the
optional default output channel. The "ref" may provide the bean name of a custom Router implementation
@@ -180,6 +180,34 @@
is not allowed, as it creates an ambiguous condition and will result in an Exception being thrown.
</para>
</note>
<para>
<emphasis>Routers and Spring Expression Language (SpEL)</emphasis>
</para>
<para>
Some times the routing logic may be simple and writing a separate class for it and configuring it as a bean may seem
like an overkill. Since Spring Integration 2.0 we offer an alternative where you can now use SpEL
(http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/expressions.html)
to implement simple computations that otherwise were implemented in a custom POJO router.
<programlisting language="xml"><![CDATA[<int:router input-channel="inChannel" expression="payload + 'Channel'"/>]]></programlisting>
In the above configuration the result channel will be computed by the SpEL expression which simply concatenates the value
of the <code>payload</code> with the literal 'Channel'
</para>
<para>
Another value of SpEL when it comes to configuring routers is that expression can actually return a <classname>Collection</classname>,
thus making every <code>&lt;router&gt;</code> a <emphasis>Recipient List Router</emphasis>. Whenever expression returns
multiple channel values Message will be forwarded to all such channels.
<programlisting language="xml"><![CDATA[<int:router input-channel="inChannel" expression="headers.channels"/>]]></programlisting>
In the above configuration lets assume that you have a message header with the name 'channels' and the value being the
List of channel names. Now, message will be sent to all channels in this list.
You ,ay also fine <emphasis>Collection Projection</emphasis> and <emphasis>Collection Selection</emphasis>
expressions usefull to select multiple channels.
See (http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/expressions.html#d0e12084)
</para>
</section>
<section id="router-annotation">

1
docs/src/reference/docbook/system-management.xml
View File

@@ -4,7 +4,6 @@
xmlns:xlink="http://www.w3.org/1999/xlink">
<title>System Management</title>
<xi:include href="./control-bus.xml"/>
<xi:include href="./jmx.xml"/>
<xi:include href="./message-history.xml"/>
</chapter>