Modified: websites/production/camel/content/seda.html
==============================================================================
--- websites/production/camel/content/seda.html (original)
+++ websites/production/camel/content/seda.html Fri Jul 10 14:19:50 2015
@@ -87,40 +87,39 @@
<tr>
<td valign="top" width="100%">
<div class="wiki-content maincontent"><h2 id="SEDA-SEDAComponent">SEDA
Component</h2><p>The <strong>seda:</strong> component provides asynchronous <a
shape="rect" class="external-link"
href="http://www.eecs.harvard.edu/~mdw/proj/seda/"; rel="nofollow">SEDA</a>
behavior, so that messages are exchanged on a <a shape="rect"
class="external-link"
href="http://java.sun.com/j2se/1.5.0/docs/api/java/util/concurrent/BlockingQueue.html";
rel="nofollow">BlockingQueue</a> and consumers are invoked in a separate
thread from the producer.</p><p>Note that queues are only visible within a
<em>single</em> <a shape="rect" href="camelcontext.html">CamelContext</a>. If
you want to communicate across <code>CamelContext</code> instances (for
example, communicating between Web applications), see the <a shape="rect"
href="vm.html">VM</a> component.</p><p>This component does not implement any
kind of persistence or recovery, if the VM terminates while messages are yet to
be processed. If you need persistence
, reliability or distributed SEDA, try using either <a shape="rect"
href="jms.html">JMS</a> or <a shape="rect"
href="activemq.html">ActiveMQ</a>.</p><div class="confluence-information-macro
confluence-information-macro-tip"><p class="title">Synchronous</p><span
class="aui-icon aui-icon-small aui-iconfont-approve
confluence-information-macro-icon"></span><div
class="confluence-information-macro-body"><p>The <a shape="rect"
href="direct.html">Direct</a> component provides synchronous invocation of any
consumers when a producer sends a message exchange.</p></div></div><h3
id="SEDA-URIformat">URI format</h3><div class="code panel pdl"
style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default"
style="font-size:12px;">seda:someName[?options]
-</pre>
-</div></div><p>Where <strong>someName</strong> can be any string that uniquely
identifies the endpoint within the current <a shape="rect"
href="camelcontext.html">CamelContext</a>.</p><p>You can append query options
to the URI in the following format:
<code>?option=value&option=value&…</code></p><h3
id="SEDA-Options">Options</h3><div class="table-wrap"><table
class="confluenceTable"><tbody><tr><th colspan="1" rowspan="1"
class="confluenceTh"><p> Name </p></th><th colspan="1" rowspan="1"
class="confluenceTh"><p> Since </p></th><th colspan="1" rowspan="1"
class="confluenceTh"><p> Default </p></th><th colspan="1" rowspan="1"
class="confluenceTh"><p> Description </p></th></tr><tr><td colspan="1"
rowspan="1" class="confluenceTd"><p> <code>size</code> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> The maximum capacity of the SED
A queue (i.e., the number of messages it can hold). The default value in Camel
2.2 or older is <code>1000</code>. From Camel 2.3 onwards, the size is
unbounded by default. <strong>Notice:</strong> Mind if you use this option,
then its the first endpoint being created with the queue name, that determines
the size. To make sure all endpoints use same size, then configure the size
option on all of them, or the first endpoint being created. From <strong>Camel
2.11</strong> onwards, a validation is taken place to ensure if using mixed
queue sizes for the same queue name, Camel would detect this and fail creating
the endpoint. </p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>concurrentConsumers</code> </p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> <code>1</code> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> Number of concurrent threads processing
exchanges. </p></t
d></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>
<code>waitForTaskToComplete</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>IfReplyExpected</code> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> Option to specify whether the caller
should wait for the async task to complete or not before continuing. The
following three options are supported: <code>Always</code>, <code>Never</code>
or <code>IfReplyExpected</code>. The first two values are self-explanatory. The
last value, <code>IfReplyExpected</code>, will only wait if the message is <a
shape="rect" href="request-reply.html">Request Reply</a> based. The default
option is <code>IfReplyExpected</code>. See more information about <a
shape="rect" href="async.html">Async</a> messaging. </p></td></tr><tr><td
colspan="1" rowspan="1" class="confluenceTd"><p> <code>timeout</code>
</p></td><td colspan="1" rowspan="1" clas
s="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>30000</code> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> Timeout (in milliseconds) before a SEDA
producer will stop waiting for an asynchronous task to complete. See
<code>waitForTaskToComplete</code> and <a shape="rect"
href="async.html">Async</a> for more details. In <strong>Camel 2.2</strong> you
can now disable timeout by using 0 or a negative value. </p></td></tr><tr><td
colspan="1" rowspan="1" class="confluenceTd"><p> <code>multipleConsumers</code>
</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>
<strong>2.2</strong> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>false</code> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> Specifies whether multiple consumers are
allowed. If enabled, you can use <a shape="rect" href="seda.html">SEDA</a> for
<a shape="rect" class="external-link" href="http://en.wikipedia.org/wiki/Publish
%E2%80%93subscribe_pattern" rel="nofollow">Publish-Subscribe</a> messaging.
That is, you can send a message to the SEDA queue and have each consumer
receive a copy of the message. When enabled, this option should be specified on
every consumer endpoint. </p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>limitConcurrentConsumers</code> </p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p> <strong>2.3</strong>
</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> <code>true</code>
</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> Whether to limit
the number of <code>concurrentConsumers</code> to the maximum of
<code>500</code>. By default, an exception will be thrown if a SEDA endpoint is
configured with a greater number. You can disable that check by turning this
option off. </p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>blockWhenFull</code> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p
> <strong>2.9</strong> </p></td><td colspan="1" rowspan="1"
> class="confluenceTd"><p> <code>false</code> </p></td><td colspan="1"
> rowspan="1" class="confluenceTd"><p> Whether a thread that sends messages to
> a full SEDA queue will block until the queue's capacity is no longer
> exhausted. By default, an exception will be thrown stating that the queue
> is full. By enabling this option, the calling thread will instead block and
> wait until the message can be accepted. </p></td></tr><tr><td colspan="1"
> rowspan="1" class="confluenceTd"><p> <code>queueSize</code> </p></td><td
> colspan="1" rowspan="1" class="confluenceTd"><p> <strong>2.9</strong>
> </p></td><td colspan="1" rowspan="1"
> class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
> class="confluenceTd"><p> <strong>Component only:</strong> The maximum
> default size (capacity of the number of messages it can hold) of the SEDA
> queue. This option is used if <code>size</code> is not in use.
> </p></td></tr><tr><td colspan="1" rowspan="
1" class="confluenceTd"><p> <code>pollTimeout</code> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> <strong>2.9.3</strong> </p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p> <code>1000</code> </p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p> <em>Consumer only</em> –
The timeout used when polling. When a timeout occurs, the consumer can check
whether it is allowed to continue running. Setting a lower value allows the
consumer to react more quickly upon shutdown. </p></td></tr><tr><td colspan="1"
rowspan="1" class="confluenceTd"><p> <code>purgeWhenStopping</code>
</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>
<strong>2.11.1</strong> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>false</code> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> Whether to purge the task queue when
stopping the consumer/route. This allows to stop faster, as any pending
messages on the queue is discarded. </p></td></
tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p> <code>queue</code>
</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>
<strong>2.12.0</strong> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> null </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> Define the queue instance which will be used by seda
endpoint </p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>
<code>queueFactory</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> <strong>2.12.0</strong> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> null </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> Define the QueueFactory which could create the queue
for the seda endpoint </p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>failIfNoConsumers</code> </p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p> <strong>2.12.0</strong>
</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> fals
e </p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> Whether the
producer should fail by throwing an exception, when sending to a SEDA queue
with no active consumers. </p></td></tr></tbody></table></div>
-<h3 id="SEDA-ChoosingBlockingQueueimplementation">Choosing BlockingQueue
implementation</h3><p><strong>Available as of Camel 2.12</strong></p><p>By
default, the SEDA component always intantiates LinkedBlockingQueue, but you can
use different implementation, you can reference your own BlockingQueue
implementation, in this case the size option is not used</p><div class="code
panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default"
style="font-size:12px;"><bean id="arrayQueue"
class="java.util.ArrayBlockingQueue">
-<constructor-arg index="0" value="10" ><!-- size -->
-<constructor-arg index="1" value="true" ><!-- fairness -->
+<script class="brush: java; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[seda:someName[?options]
+]]></script>
+</div></div><p>Where <strong>someName</strong> can be any string that uniquely
identifies the endpoint within the current <a shape="rect"
href="camelcontext.html">CamelContext</a>.</p><p>You can append query options
to the URI in the following format:
<code>?option=value&option=value&…</code></p><h3
id="SEDA-Options">Options</h3><div class="table-wrap"><table
class="confluenceTable"><tbody><tr><th colspan="1" rowspan="1"
class="confluenceTh"><p>Name</p></th><th colspan="1" rowspan="1"
class="confluenceTh"><p>Since</p></th><th colspan="1" rowspan="1"
class="confluenceTh"><p>Default</p></th><th colspan="1" rowspan="1"
class="confluenceTh"><p>Description</p></th></tr><tr><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>size</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p>The maximum capacity of the SEDA queue (i.
e., the number of messages it can hold). The default value in Camel 2.2 or
older is <code>1000</code>. From Camel 2.3 onwards, the size is unbounded by
default. <strong>Notice:</strong> Mind if you use this option, then its the
first endpoint being created with the queue name, that determines the size. To
make sure all endpoints use same size, then configure the size option on all of
them, or the first endpoint being created. From <strong>Camel 2.11</strong>
onwards, a validation is taken place to ensure if using mixed queue sizes for
the same queue name, Camel would detect this and fail creating the
endpoint.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>concurrentConsumers</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>1</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p>Number of concurrent threads processing
exchanges.</p></td></tr><tr><td col
span="1" rowspan="1"
class="confluenceTd"><p><code>waitForTaskToComplete</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>IfReplyExpected</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p>Option to specify whether the
caller should wait for the async task to complete or not before continuing. The
following three options are supported: <code>Always</code>, <code>Never</code>
or <code>IfReplyExpected</code>. The first two values are self-explanatory. The
last value, <code>IfReplyExpected</code>, will only wait if the message is <a
shape="rect" href="request-reply.html">Request Reply</a> based. The default
option is <code>IfReplyExpected</code>. See more information about <a
shape="rect" href="async.html">Async</a> messaging.</p></td></tr><tr><td
colspan="1" rowspan="1"
class="confluenceTd"><p><code>timeout</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> 
</p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>30000</code></p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p>Timeout (in milliseconds) before a SEDA producer will
stop waiting for an asynchronous task to complete. See
<code>waitForTaskToComplete</code> and <a shape="rect"
href="async.html">Async</a> for more details. In <strong>Camel 2.2</strong> you
can now disable timeout by using 0 or a negative value.</p></td></tr><tr><td
colspan="1" rowspan="1"
class="confluenceTd"><p><code>multipleConsumers</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><strong>2.2</strong></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p>Specifies whether multiple
consumers are allowed. If enabled, you can use <a shape="rect"
href="seda.html">SEDA</a> for <a shape="rect" class="external-link"
href="http://en.wikipedia.org/wiki/Publish%E2%80%93subscribe_pattern"; rel="nofo
llow">Publish-Subscribe</a> messaging. That is, you can send a message to the
SEDA queue and have each consumer receive a copy of the message. When enabled,
this option should be specified on every consumer
endpoint.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>limitConcurrentConsumers</code></p></td><td
colspan="1" rowspan="1"
class="confluenceTd"><p><strong>2.3</strong></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>true</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p>Whether to limit the number of
<code>concurrentConsumers</code> to the maximum of <code>500</code>. By
default, an exception will be thrown if a SEDA endpoint is configured with a
greater number. You can disable that check by turning this option
off.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>blockWhenFull</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><strong>2.9</strong></p></td><td
colspan="1" ro
wspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p>Whether a thread that sends messages to a
full SEDA queue will block until the queue's capacity is no longer exhausted.
By default, an exception will be thrown stating that the queue is full. By
enabling this option, the calling thread will instead block and wait until the
message can be accepted.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>queueSize</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><strong>2.9</strong></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><strong>Component only:</strong> The
maximum default size (capacity of the number of messages it can hold) of the
SEDA queue. This option is used if <code>size</code> is not in
use.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>pollTimeout</code></p></td><
td colspan="1" rowspan="1"
class="confluenceTd"><p><strong>2.9.3</strong></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>1000</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><em>Consumer only</em> – The timeout
used when polling. When a timeout occurs, the consumer can check whether it is
allowed to continue running. Setting a lower value allows the consumer to react
more quickly upon shutdown.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>purgeWhenStopping</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><strong>2.11.1</strong></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p>Whether to purge the task queue
when stopping the consumer/route. This allows to stop faster, as any pending
messages on the queue is discarded.</p></td></tr><tr><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>queue</code>
</p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p><strong>2.12.0</strong></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p>null</p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p>Define the queue instance which will be used by seda
endpoint</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>queueFactory</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><strong>2.12.0</strong></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p>null</p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p>Define the QueueFactory which could create
the queue for the seda endpoint</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>failIfNoConsumers</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><strong>2.12.0</strong></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p>false</p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p>Whether the producer should fail by
throwing an exception, when sending to a SEDA queue with no active
consumers.</p><p>Only one of the options discardIfNoConsumers and
failIfNoConsumers can be enabled at the same time.</p></td></tr><tr><td
colspan="1" rowspan="1"
class="confluenceTd"><code>discardIfNoConsumers</code></td><td colspan="1"
rowspan="1" class="confluenceTd"><strong>2.16</strong></td><td colspan="1"
rowspan="1" class="confluenceTd"><code>false</code></td><td colspan="1"
rowspan="1" class="confluenceTd"><p>Whether the producer should discard the
message (do not add the message to the queue), when sending to a SEDA queue
with no active consumers.</p><p><span>Only one of the options
discardIfNoConsumers and failIfNoConsumers can be enabled at the same
time.</span></p></td></tr></tbody></table></div><h3
id="SEDA-ChoosingBlockingQueueimplementation">Choosing BlockingQueue
implementation</h3><p><strong>Available as of Camel 2.12</strong></p><p>By
default, the SEDA component always intantiates LinkedBlockingQueue
, but you can use different implementation, you can reference your own
BlockingQueue implementation, in this case the size option is not used</p><div
class="code panel pdl" style="border-width: 1px;"><div class="codeContent
panelContent pdl">
+<script class="brush: java; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[<bean id="arrayQueue"
class="java.util.ArrayBlockingQueue">
+<constructor-arg index="0" value="10" ><!-- size
-->
+<constructor-arg index="1" value="true" ><!--
fairness -->
</bean>
<!-- ... and later -->
<from>seda:array?queue=#arrayQueue</from>
-</pre>
+]]></script>
</div></div><p>Or you can reference a BlockingQueueFactory implementation, 3
implementations are provided LinkedBlockingQueueFactory,
ArrayBlockingQueueFactory and PriorityBlockingQueueFactory:</p><div class="code
panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default"
style="font-size:12px;"><bean id="priorityQueueFactory"
class="org.apache.camel.component.seda.PriorityBlockingQueueFactory">
-<property name="comparator">
-<bean class="org.apache.camel.demo.MyExchangeComparator" />
+<script class="brush: java; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[<bean id="priorityQueueFactory"
class="org.apache.camel.component.seda.PriorityBlockingQueueFactory">
+<property name="comparator">
+<bean class="org.apache.camel.demo.MyExchangeComparator" />
</property>
</bean>
<!-- ... and later -->
<from>seda:priority?queueFactory=#priorityQueueFactory&size=100</from>
-</pre>
+]]></script>
</div></div><h3 id="SEDA-UseofRequestReply">Use of Request Reply</h3><p>The <a
shape="rect" href="seda.html">SEDA</a> component supports using <a shape="rect"
href="request-reply.html">Request Reply</a>, where the caller will wait for the
<a shape="rect" href="async.html">Async</a> route to complete. For
instance:</p><div class="code panel pdl" style="border-width: 1px;"><div
class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default"
style="font-size:12px;">from("mina:tcp://0.0.0.0:9876?textline=true&sync=true").to("seda:input");
+<script class="brush: java; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[from("mina:tcp://0.0.0.0:9876?textline=true&sync=true").to("seda:input");
-from("seda:input").to("bean:processInput").to("bean:createResponse");
-</pre>
+from("seda:input").to("bean:processInput").to("bean:createResponse");
+]]></script>
</div></div><p>In the route above, we have a TCP listener on port 9876 that
accepts incoming requests. The request is routed to the <code>seda:input</code>
queue. As it is a <a shape="rect" href="request-reply.html">Request Reply</a>
message, we wait for the response. When the consumer on the
<code>seda:input</code> queue is complete, it copies the response to the
original message response.</p><div class="confluence-information-macro
confluence-information-macro-note"><p class="title">until 2.2: Works only with
2 endpoints</p><span class="aui-icon aui-icon-small aui-iconfont-warning
confluence-information-macro-icon"></span><div
class="confluence-information-macro-body"><p>Using <a shape="rect"
href="request-reply.html">Request Reply</a> over <a shape="rect"
href="seda.html">SEDA</a> or <a shape="rect" href="vm.html">VM</a> only works
with 2 endpoints. You <strong>cannot</strong> chain endpoints by sending to A
-> B -> C etc. Only between A -> B. The reason is the implement
ation logic is fairly simple. To support 3+ endpoints makes the logic much
more complex to handle ordering and notification between the waiting threads
properly.</p><p>This has been improved in <strong>Camel 2.3</strong> onwards,
which allows you to chain as many endpoints as you like.</p></div></div><h3
id="SEDA-Concurrentconsumers">Concurrent consumers</h3><p>By default, the SEDA
endpoint uses a single consumer thread, but you can configure it to use
concurrent consumer threads. So instead of thread pools you can use:</p><div
class="code panel pdl" style="border-width: 1px;"><div class="codeContent
panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default"
style="font-size:12px;">from("seda:stageName?concurrentConsumers=5").process(...)
-</pre>
+<script class="brush: java; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[from("seda:stageName?concurrentConsumers=5").process(...)
+]]></script>
</div></div><p>As for the difference between the two, note a <em>thread
pool</em> can increase/shrink dynamically at runtime depending on load, whereas
the number of concurrent consumers is always fixed.</p><h3
id="SEDA-Threadpools">Thread pools</h3><p>Be aware that adding a thread pool to
a SEDA endpoint by doing something like:</p><div class="code panel pdl"
style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default"
style="font-size:12px;">from("seda:stageName").thread(5).process(...)
-</pre>
+<script class="brush: java; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[from("seda:stageName").thread(5).process(...)
+]]></script>
</div></div><p>Can wind up with two <code>BlockQueues</code>: one from the
SEDA endpoint, and one from the workqueue of the thread pool, which may not be
what you want. Instead, you might wish to configure a <a shape="rect"
href="direct.html">Direct</a> endpoint with a thread pool, which can process
messages both synchronously and asynchronously. For example:</p><div
class="code panel pdl" style="border-width: 1px;"><div class="codeContent
panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default"
style="font-size:12px;">from("direct:stageName").thread(5).process(...)
-</pre>
+<script class="brush: java; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[from("direct:stageName").thread(5).process(...)
+]]></script>
</div></div><p>You can also directly configure number of threads that process
messages on a SEDA endpoint using the <code>concurrentConsumers</code>
option.</p><h3 id="SEDA-Sample">Sample</h3><p>In the route below we use the
SEDA queue to send the request to this async queue to be able to send a
fire-and-forget message for further processing in another thread, and return a
constant reply in this thread to the original caller.</p><div class="code panel
pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
<script class="brush: java; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[
public void configure() throws Exception {
@@ -133,12 +132,12 @@ public void configure() throws Exception
from("seda:next").to("mock:result");
}
]]></script>
-</div></div><p>Here we send a Hello World message and expects the reply to be
OK.</p><div class="code panel pdl" style="border-width: 1px;"><div
class="codeContent panelContent pdl">
+</div></div>Here we send a Hello World message and expects the reply to be
OK.<div class="code panel pdl" style="border-width: 1px;"><div
class="codeContent panelContent pdl">
<script class="brush: java; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[
Object out = template.requestBody("direct:start", "Hello
World");
assertEquals("OK", out);
]]></script>
-</div></div><p>The "Hello World" message will be consumed from the SEDA queue
from another thread for further processing. Since this is from a unit test, it
will be sent to a <code>mock</code> endpoint where we can do assertions in the
unit test.</p><h3 id="SEDA-UsingmultipleConsumers">Using
multipleConsumers</h3><p><strong>Available as of Camel 2.2</strong></p><p>In
this example we have defined two consumers and registered them as spring
beans.</p><div class="code panel pdl" style="border-width: 1px;"><div
class="codeContent panelContent pdl">
+</div></div>The "Hello World" message will be consumed from the SEDA queue
from another thread for further processing. Since this is from a unit test, it
will be sent to a <code>mock</code> endpoint where we can do assertions in the
unit test.<h3 id="SEDA-UsingmultipleConsumers">Using
multipleConsumers</h3><p><strong>Available as of Camel 2.2</strong></p><p>In
this example we have defined two consumers and registered them as spring
beans.</p><div class="code panel pdl" style="border-width: 1px;"><div
class="codeContent panelContent pdl">
<script class="brush: xml; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[
<!-- define the consumers as spring beans -->
<bean id="consumer1"
class="org.apache.camel.spring.example.FooEventConsumer"/>
@@ -150,7 +149,7 @@ assertEquals("OK", out);
<endpoint id="foo"
uri="seda:foo?multipleConsumers=true"/>
</camelContext>
]]></script>
-</div></div><p>Since we have specified <strong>multipleConsumers=true</strong>
on the seda foo endpoint we can have those two consumers receive their own copy
of the message as a kind of pub-sub style messaging.</p><p>As the beans are
part of an unit test they simply send the message to a mock endpoint, but
notice how we can use @Consume to consume from the seda queue.</p><div
class="code panel pdl" style="border-width: 1px;"><div class="codeContent
panelContent pdl">
+</div></div>Since we have specified <strong>multipleConsumers=true</strong> on
the seda foo endpoint we can have those two consumers receive their own copy of
the message as a kind of pub-sub style messaging.<p>As the beans are part of an
unit test they simply send the message to a mock endpoint, but notice how we
can use @Consume to consume from the seda queue.</p><div class="code panel pdl"
style="border-width: 1px;"><div class="codeContent panelContent pdl">
<script class="brush: java; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[
public class FooEventConsumer {
@@ -165,9 +164,9 @@ public class FooEventConsumer {
}
]]></script>
</div></div><h3 id="SEDA-Extractingqueueinformation.">Extracting queue
information.</h3><p>If needed, information such as queue size, etc. can be
obtained without using JMX in this fashion:</p><div class="code panel pdl"
style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default"
style="font-size:12px;">SedaEndpoint seda = context.getEndpoint("seda:xxxx");
+<script class="brush: java; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[SedaEndpoint seda =
context.getEndpoint("seda:xxxx");
int size = seda.getExchanges().size();
-</pre>
+]]></script>
</div></div><p></p><h3 id="SEDA-SeeAlso">See Also</h3>
<ul><li><a shape="rect" href="configuring-camel.html">Configuring
Camel</a></li><li><a shape="rect"
href="component.html">Component</a></li><li><a shape="rect"
href="endpoint.html">Endpoint</a></li><li><a shape="rect"
href="getting-started.html">Getting Started</a></li></ul><ul
class="alternate"><li><a shape="rect" href="vm.html">VM</a></li><li><a
shape="rect" href="disruptor.html">Disruptor</a></li><li><a shape="rect"
href="direct.html">Direct</a></li><li><a shape="rect"
href="async.html">Async</a></li></ul></div>
</td>
@@ -175,7 +174,7 @@ int size = seda.getExchanges().size();
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@@ -183,7 +182,7 @@ int size = seda.getExchanges().size();
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