Description of problem:
If a variable/expression is used in a host's managed server configuration's attributes, it results in managed server discovery being aborted and no managed servers being discovered or imported for the parent host.

For example, from host.xml:

    <servers>
        <server name="server-one" group="main-server-group" auto-start="${server.autostart:true}">
            <socket-bindings port-offset="0"/>
        </server>
        <server name="server-two" group="main-server-group" auto-start="true">
            <socket-bindings port-offset="${server.portoffset.02:50}"/>
        </server>
        <server name="server-three" group="other-server-group" auto-start="${server.autostart:true}">
            <socket-bindings port-offset="${server.portoffset.03:100}"/>
        </server>
    </servers>

Such configuration would result in discovery failure. This is due to a type cast exception that provides very little details:

    Discovery for a ResourceType[id=0, name=Managed Server, plugin=JBossAS7, category=Server] failed for process  :java.util.LinkedHashMap cannot be cast to java.lang.Boolean

Version-Release number of selected component (if applicable):
3.3.0.GA Build Number: 4f16df3:e347f77

How reproducible:
Always

Steps to Reproduce:
1.  Install, configure, and start JBoss EAP 6.3 domain.
2.  Update the master host's managed server configuration for server-one to use a variable/property expression for its auto-start and port-offset attributes:

        # server-one
        /opt/jboss/eap/jboss-eap/bin/jboss-cli.sh --connect --command='/host=master/server-config=server-one:write-attribute(name=auto-start, value=${server.autostart:true})'
        /opt/jboss/eap/jboss-eap/bin/jboss-cli.sh --connect --command='/host=master/server-config=server-one:write-attribute(name=socket-binding-port-offset, value=${server.portoffset.01:0})'

3.  Confirm that the configuration was properly updated:

        /opt/jboss/eap/jboss-eap/bin/jboss-cli.sh --connect --command='/host=master/server-config=server-one:read-resource'
                ...
                "auto-start" => expression "${server.autostart:true}",
                ...
                "socket-binding-port-offset" => expression "${server.portoffset.01:0}",
                ...

4.  Restart the JBoss EAP domain for the changes to take affect.
5.  Install and start JBoss ON 3.3 system.
6.  Import the EAP Domain Controller (master 127.0.0.1:9990) JBossAS7 Host Controller resource from the discovery queue.
7.  Set the management user and password properties under the connection settings for the newly imported EAP Domain Controller resource.
8.  Invoke the platform resource's Run Autodiscovery operation with its Detailed Discovery parameter set to Yes.
9.  Wait for discovery operation to complete.

Actual results:
agent.log contains the following warning and managed server discovery is aborted and there are no managed resources discovered or auto-imported:

    WARN  [ResourceDiscoveryComponent.invoker.daemon-4] (rhq.modules.plugins.jbossas7.ManagedASDiscovery)- Discovery for a ResourceType[id=0, name=Managed Server, plugin=JBossAS7, category=Server] failed for process  :java.util.LinkedHashMap cannot be cast to java.lang.Boolean

If only socket-binding-port-offset is set to an expression, the same warning appears but the cast type is java.lang.Integer.

Expected results:
No error or warning related to "LinkedHashMap cannot be case to java.lang.*" and server-one, server-two, and server-three managed servers are all discovered and properly imported into inventory.

Additional info:
This bug is a result of blindly casting a de-typed return value to an incompatible type in ManagedASDiscovery.getManagedServers. Specifically:

193[2]:    info.autoStart = (Boolean) map.get("auto-start");
   194:    Integer offset = (Integer) map.get("socket-binding-port-offset");

This issue is similar to what was captured in Bug 1072543 in regards to metric collection.


[1]: https://github.com/rhq-project/rhq/blob/RHQ_4_12_0/modules/plugins/jboss-as-7/src/main/java/org/rhq/modules/plugins/jbossas7/ManagedASDiscovery.java#L175
[2]: https://github.com/rhq-project/rhq/blob/RHQ_4_12_0/modules/plugins/jboss-as-7/src/main/java/org/rhq/modules/plugins/jbossas7/ManagedASDiscovery.java#L193