[INFO   ] (kernel): info report
-----------------------------------------------------------
Merlin Kernel Environment Listing
-----------------------------------------------------------

  ${user.dir} == D:\dev\avalon\tutorials\hello
  ${user.home} == C:\WINNT\Profiles\mcconnell

  ${avalon.repository.cache} == D:\merlin\system
  ${avalon.repository.online} == true
  ${avalon.repository.hosts} == http://www.dpml.net,http://www.ibiblio.org/maven

  ${merlin.lang} == null
  ${merlin.home} == D:\merlin
  ${merlin.system} == D:\merlin\system
  ${merlin.config} == D:\merlin\config
  ${merlin.kernel} == file:/D:/merlin/config/kernel.xml
  ${merlin.logging.implementation} == 
     artifact:avalon-logging/avalon-logging-logkit-impl#1.0.dev-0
  ${merlin.logging.config} == null
  ${merlin.runtime} == 
     artifact:avalon-activation/avalon-activation-impl#2.0.dev-0
  ${merlin.override} == null
  ${merlin.dir} == D:\dev\avalon\tutorials\hello
  ${merlin.temp} == C:\TEMP
  ${merlin.context} == D:\dev\avalon\tutorials\hello\home
  ${merlin.anchor} == D:\dev\avalon\tutorials\hello
  ${merlin.info} == true
  ${merlin.debug} == false
  ${merlin.audit} == false
  ${merlin.server} == false
  ${merlin.autostart} == true
  ${merlin.code.security.enabled} == false
  ${merlin.deployment.timeout} == 1000
  ${merlin.repository} == D:\avalon\repository
  ${merlin.repository.hosts} == http://www.dpml.net/,http://www.ibiblio.org/maven/
  ${merlin.deployment} == file:/${user.dir}/target/classes/

-----------------------------------------------------------
[INFO   ] (tutorial.hello): Hello World!

Targetted debugging using -config

We can also override the logging priority for the component using a target override directive. The following target tells merlin to assign logging at DEBUG prioririty for the "tutorial" container.

${basedir}\conf\config.xml

<targets>
  <target path="/tutorial">
    <categories priority="DEBUG"/>
  </target>
</targets>

The behind the scenes activity is detailed under the <component-path>.appliance logging category as shown below.

$ merlin -execute target\classes -config conf\config.xml

[DEBUG  ] (tutorial): assembly phase
[DEBUG  ] (tutorial): commissioning component [hello]
[DEBUG  ] (tutorial.hello.lifecycle): incarnation
[DEBUG  ] (tutorial.hello.lifecycle): instantiating component with 1 arguments.
[INFO   ] (tutorial.hello): Hello World!
[DEBUG  ] (tutorial): commissioning of [hello] completed in 93 milliseconds
[DEBUG  ] (tutorial): decommissioning
[DEBUG  ] (tutorial.hello.lifecycle): etherialization
[DEBUG  ] (tutorial.hello.lifecycle): applying disposal
[DEBUG  ] (tutorial.hello): disposal

The following information presents the above listing step by step.

Launch merlin in execute mode using the "target\classes" directory as an implicit classpath entry and a deployment scenario defined in the file target\classes\BLOCK-INF\block.xml using an overriding configuration qualifying the logging priorities.

$ merlin -execute target\classes -config conf\config.xml

The assembly phase checks the component for any service dependencies and resolves them automatically. In our demonstration component there are no dependencies. Later tutorials will revisit this aspect.

[DEBUG  ] (tutorial): assembly phase

As the component has been declared in the block.xml file, the default deployment policy is to deploy on startup. The following log entry is issued by the container responsible for commissioning of the hello component.

[DEBUG  ] (tutorial): commissioning component [hello]

Deployment commences with the initialization of a new instance.

[DEBUG  ] (tutorial.hello.lifecycle): incarnation
[DEBUG  ] (tutorial.hello.lifecycle): instantiating component with 1 arguments.
[INFO   ] (tutorial.hello): Hello World!

If the component implements any lifecycle interfaces, the container will process the stages following instance instiation. In our example we have already supplied arguments via a constructor so no additional lifecycle processing is required.

[DEBUG  ] (tutorial): commissioning of [hello] completed in 93 milliseconds

When merlin is launched in execute mode (using the -execute command line parameter), Merlin automatically initiates container decomissioning once deployment is complete. If the -execute parameter is absent, Merlin will continue until a ^C interup is encountered.

Decommissioning of a component involves stopping the compoent if it implements the Startable interface, followed by component disposal.

[DEBUG  ] (tutorial): decommissioning
[DEBUG  ] (tutorial.hello.lifecycle): etherialization

The -debug command line switch

For a really deep look inside Merlin, you can select the -debug command line switch. Some of the addition information visible here includes the setup of classloaders

$ merlin -execute target\classes -debug

[DEBUG  ] (kernel.logger): logging system established
[DEBUG  ] (kernel.logger): adding category [kernel]
[DEBUG  ] (kernel): logging system established
[DEBUG  ] (kernel): repository established: 
   D:\system\maven\repository, http://www.dpml.net/, 
   http://www.ibiblio.org/maven/
[DEBUG  ] (kernel.logger): adding category [kernel]
[DEBUG  ] (kernel): building application model
[DEBUG  ] (kernel.logger): adding root category
[DEBUG  ] (kernel.logger): adding root category
[DEBUG  ] (kernel.logger): adding root category
[DEBUG  ] (classloader): base: ${user.dir}
[DEBUG  ] (classloader): base=[D:\dev\avalon\tutorials\hello]
[DEBUG  ] (classloader): classpath:
[DEBUG  ] (classloader.types): type install count: 0
[DEBUG  ] (classloader.types): type registration complete
[DEBUG  ] (kernel): state: initializing
[DEBUG  ] (kernel): kernel established
[DEBUG  ] (kernel): state: initialized
[DEBUG  ] (kernel): install phase
[DEBUG  ] (kernel): installing: file:/${user.dir}/target/classes/
[DEBUG  ] (): including composite block: 
  file:/D:/dev/avalon/tutorials/hello/target/classes/BLOCK-INF/block.xml
[DEBUG  ] (): installing: tutorial
[DEBUG  ] (kernel.logger): adding category [tutorial]
[DEBUG  ] (kernel.logger): adding category [tutorial]
[DEBUG  ] (tutorial): creating child classloader for: [tutorial]
[DEBUG  ] (tutorial.classloader): base: ${user.dir}
[DEBUG  ] (tutorial): implicit entries: 1
[DEBUG  ] (tutorial.classloader): base=[D:\dev\avalon\tutorials\hello]
[DEBUG  ] (tutorial.classloader): classpath: file:/${user.dir}/target/classes/
[DEBUG  ] (tutorial.classloader.scanner): scanning: file:/${user.dir}/target/classes/
[DEBUG  ] (tutorial.classloader.scanner): type: tutorial.HelloComponent
[DEBUG  ] (tutorial.classloader.types): type install count: 1
[DEBUG  ] (tutorial.classloader.types): registered [type:tutorial.HelloComponent/1].
[DEBUG  ] (tutorial.classloader.types): type registration complete
[DEBUG  ] (kernel.logger): adding category [tutorial]
[DEBUG  ] (kernel.logger): adding category [tutorial.hello]
[DEBUG  ] (kernel): customize phase
[DEBUG  ] (kernel): startup phase
[DEBUG  ] (kernel): application assembly
[DEBUG  ] (kernel): state: assembly
[DEBUG  ] (): assembly phase
[DEBUG  ] (tutorial): assembly phase
[DEBUG  ] (kernel): application deployment
[DEBUG  ] (kernel): state: deployment
[DEBUG  ] (): commissioning container [tutorial]
[DEBUG  ] (tutorial): commissioning component [hello]
[DEBUG  ] (tutorial.hello.lifecycle): incarnation
[DEBUG  ] (tutorial.hello.lifecycle): instantiating component with 1 arguments.
[INFO   ] (tutorial.hello): Hello World
[DEBUG  ] (tutorial): commissioning of [hello] completed in 94 milliseconds
[DEBUG  ] (): commissioning of [tutorial] completed in 156 milliseconds
[DEBUG  ] (kernel): state: started
[DEBUG  ] (kernel): shutdown phase
[DEBUG  ] (kernel): state: stopping
[DEBUG  ] (kernel): state: decommissioning
[DEBUG  ] (): decommissioning
[DEBUG  ] (tutorial): decommissioning
[DEBUG  ] (tutorial.hello.lifecycle): etherialization
[DEBUG  ] (kernel): state: stopped
[DEBUG  ] (kernel): disposal
[DEBUG  ] (kernel): shutdown event
[DEBUG  ] (kernel): disposal

Next Steps

We are now ready to move onto the next series of tutorials dealing with component configuration management.