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>
<section id="router-namespace"> <section id="router-namespace">
<title>The &lt;router&gt; element</title> <title>Namespace support for Router - &lt;router&gt; element</title>
<para> <para>
The "router" element provides a simple way to connect a router to an input channel, and also accepts the 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 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. is not allowed, as it creates an ambiguous condition and will result in an Exception being thrown.
</para> </para>
</note> </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>
<section id="router-annotation"> <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"> xmlns:xlink="http://www.w3.org/1999/xlink">
<title>System Management</title> <title>System Management</title>
<xi:include href="./control-bus.xml"/>
<xi:include href="./jmx.xml"/> <xi:include href="./jmx.xml"/>
<xi:include href="./message-history.xml"/> <xi:include href="./message-history.xml"/>
</chapter> </chapter>