Controlling number of threads in Mule - threadpool

Question

I'm using Mule 3.3.1 Community Edition.
I have a flow that accepts HTTP requests. This runs successfully.
<flow name="TestFlow">
<http:inbound-endpoint exchange-pattern="request-response"
host="localhost" port="8088" path="test" doc:name="HTTP" mimeType="text/plain"
encoding="UTF-8"/>
<logger level="INFO" category="hello" doc:name="Logger"/>
</flow>
The service needs to be single-threaded so that messages are handled strictly in the order in which they are received. My thought was to set maxThreadsActive=1 and maxBufferSize=100 to get my desired behavior. However, I can't get any control over threads to work.
At this point I'm just trying to get a thread profile working, regardless of the number of threads. I added a threading-profile exactly out of the current version of the Manning book Mule in Action, but Mule rejects it as "Invalid content" and won't run.
<flow name="TestFlow">
<threading-profile maxBufferSize="100" maxThreadsActive="20" maxThreadsIdle="10"
threadTTL="60000" poolExhaustedAction="RUN" />
<http:inbound-endpoint exchange-pattern="request-response"
host="localhost" port="8088" path="test" doc:name="HTTP" mimeType="text/plain"
encoding="UTF-8"/>
<logger level="INFO" category="hello" doc:name="Logger"/>
</flow>
I commented that out and moved up to a configuration block.
<configuration>
<default-threading-profile maxThreadsActive="20" maxBufferSize="100"
poolExhaustedAction="RUN" />
</configuration>
<flow name="TestFlow">
<http:inbound-endpoint exchange-pattern="request-response"
host="localhost" port="8088" path="test" doc:name="HTTP" mimeType="text/plain"
encoding="UTF-8"/>
<logger level="INFO" category="hello" doc:name="Logger"/>
</flow>
Mule accepts this, but the service no longer returns; the client simply hangs waiting for a response.
How do I configure my flow so that I can control thread pool size and, once that's done, so that only one thread is available in the pool?

Answer 1

You need to configure the receiver-threading-profile of the HTTP connector:
<http:connector name="httpConnector">
<receiver-threading-profile maxThreadsActive="1" />
</http:connector>