Ant - printing a collection - map - ant

Question

I have an ant script that is executing a jmx get task:
<jmx:get
name="java.lang:type=GarbageCollector,name=Copy"
attribute="LastGcInfo"
resultproperty="CopyLastGcInfo"
/>
Now, the LastGcInfo attribute has a map Map called memoryUsageBeforeGC. In this map there is a pair with a key called "value". Althoug I am unable to elicit it and print it out. I have tried to accomplish it like that:
<echo>${CopyLastGcInfo.memoryUsageBeforeGc.value.used}</echo>
<echo>${CopyLastGcInfo.memoryUsageBeforeGc.0.used}</echo>
<echo>${CopyLastGcInfo.memoryUsageBeforeGc.used}</echo>
That didn't work. Do you have any suggestions how to tackle this problem?
Thanks.

Answer 1

The following example worked for me:
<project name="Catalina Ant JMX" xmlns:jmx="antlib:org.apache.catalina.ant.jmx" default="jmx">
<target name="jmx" description="Show JMX stats">
<jmx:open host="localhost" port="9012" username="controlRole" password="tomcat"/>
<jmx:get name="java.lang:type=GarbageCollector,name=Copy"
attribute="LastGcInfo"
resultproperty="CopyLastGcInfo"
echo="false"
/>
<echo>
memoryUsageBeforeGc
===================
Perm Gen.used=${CopyLastGcInfo.memoryUsageBeforeGc.Perm Gen.used}
Tenured Gen.used=${CopyLastGcInfo.memoryUsageBeforeGc.Tenured Gen.used}
Eden Space.used=${CopyLastGcInfo.memoryUsageBeforeGc.Eden Space.used}
Code Cache.used=${CopyLastGcInfo.memoryUsageBeforeGc.Code Cache.used}
Survivor Space.used=${CopyLastGcInfo.memoryUsageBeforeGc.Survivor Space.used}
</echo>
</target>
</project>
Example output
jmx:
[echo]
[echo] memoryUsageBeforeGc
[echo] ===================
[echo] Perm Gen.used=9660888
[echo] Tenured Gen.used=8393792
[echo] Eden Space.used=4456448
[echo] Code Cache.used=2038016
[echo] Survivor Space.used=172784
[echo]
Note
The "echo" attribute of the "jmx:query" task can be used to see the ANT properties and values created by the task. Useful for troubleshooting.