Messager Logging Configuration

Logging behaviors of Message Facility Messager s are configured by MetaBundle s having the same name. Default Messager s are configured by default MetaBundle s.

Look at this meta resource file (tutor/msg.meta):

<?xml version="1.0" encoding="UTF-8"?>
<java>
  <messaging revealLocation="false" />

  <logging level="CONFIG">

    <formatters>
      <xml class="java.util.logging.XMLFormatter" />
    </formatters>

    <handlers>
      <msg-xml encoding="UTF-8" level="ALL"
        class="av.msg.logging.FileHandler">
        <formatter>xml</formatter>
        <property name="append" value="true" />
        <property name="file" value="%h/msglog%u.xml" />
        <property name="autoFlush" value="true" />
      </msg-xml>
    </handlers>

    <handler>console</handler>
    <handler>msg-xml</handler>

  </logging>
</java>

This snippet is from tutor/msg.meta

It configures Messager tutor.msg, and provides the default configuration for all its descendants.

And one of its descendants - Messager tutor.msg.Reuse, is just configured to override the logging level by meta resource tutor/msg/Reuse.meta

<?xml version="1.0" encoding="UTF-8"?>
<java>

  <messaging revealLocation="false" />

  <logging level="ALL" />

</java>

This snippet is from tutor/msg/Reuse.meta

These meta resources (XML files) will just take effect when you put them on your Java Classpath.

The configuration format is somewhat self-explaining:

• You can define new named formatters under XPath logging/formatters. The node name will turn out to be the formatter name, used to reference it by handler definitions. And you need to specify its Java class name with the @class attribute. Extra nested <property name="xxx" value="xxx" /> elements can be supplied as well as for the handlers. These properties will be interpreted as Bean Properties and writen to the constructed formatter instance.
• You can define new named handlers under XPath logging/handlers. The node name will turn out to be the handler name, used to reference it by Messager handler lists. You need to supply the handler's Java class name with the @class attribute. And @encoding and @level are optional if you want specific values rather than defaults. Nested <property name="xxx" value="xxx" /> elements can be supplied, as Bean Properties to be writen to the constructed handler instance.
• List all intended handlers for the configured messager, with handler elements under logging, as their text content referencing defined handlers via name. The referenced handlers can either be defined within the same meta resource, or defined in any of its ancestors.
• Named formatters and handlers can all be inherited from ancestor meta bundles.

As you may guess, the <handler>console</handler> is referencing a handler defined in the meta resource provided by Message Facility that for all messagers.

<?xml version="1.0" encoding="UTF-8"?>
<java>

  <messaging revealLocation="false" />

  <logging level="CONFIG">

    <formatters>
      <simple class="java.util.logging.SimpleFormatter" />
    </formatters>

    <handlers>
      <console class="java.util.logging.ConsoleHandler" level="ALL">
        <formatter>simple</formatter>
      </console>
    </handlers>

    <handler>console</handler>

  </logging>

</java>

This snippet is from default.meta extracted from av6base.jar.

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