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@@ -13,7 +13,7 @@
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<p>
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<p>
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The Jakarta Commons Logging (JCL) provides a Log interface that
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The Jakarta Commons Logging (JCL) provides a Log interface that
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is intended to be both light-weight and independent of numerous logging toolkits.
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is intended to be both light-weight and independent of numerous logging toolkits.
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It provides the middleware/tooling developer a simple
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It provides the middleware/tooling developer with a simple
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logging abstraction, that allows the user (application developer) to plug in
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logging abstraction, that allows the user (application developer) to plug in
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a specific logging implementation.
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a specific logging implementation.
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</p>
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</p>
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@@ -25,8 +25,8 @@ Familiarity with high-level details of various Logging implementations is presum
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<p>
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<p>
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The Jakarta Commons Logging provides a Log interface with thin-wrapper implementations for
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The Jakarta Commons Logging provides a Log interface with thin-wrapper implementations for
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other logging tools, including
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other logging tools, including
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<a href="http://jakarta.apache.org/log4j/docs/index.html">Log4J</a>,
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<a href="http://logging.apache.org/log4j/docs/index.html">Log4J</a>,
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<a href="http://jakarta.apache.org/avalon/logkit/index.html">Avalon LogKit</a>,
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<a href="http://avalon.apache.org/logkit/index.html">Avalon LogKit</a>,
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and
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and
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<a>JDK 1.4</a>.
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<a>JDK 1.4</a>.
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The interface maps closely to Log4J and LogKit.
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The interface maps closely to Log4J and LogKit.
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@@ -187,7 +187,7 @@ only needs to execute in support of logging,
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that otherwise introduces undesirable runtime overhead
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that otherwise introduces undesirable runtime overhead
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in the general case (logging disabled).
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in the general case (logging disabled).
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Examples are multiple parameters, or expressions (i.e. string + " more") for parameters.
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Examples are multiple parameters, or expressions (i.e. string + " more") for parameters.
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Use the guard methods of the form <code>log.is<<i>Priority</i>>()</code> to verify
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Use the guard methods of the form <code>log.is<<i>Priority</i>>()</code> to verify
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that logging should be performed, before incurring the overhead of the logging method call.
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that logging should be performed, before incurring the overhead of the logging method call.
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Yes, the logging methods will perform the same check, but only after resolving parameters.
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Yes, the logging methods will perform the same check, but only after resolving parameters.
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</p>
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</p>
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@@ -223,7 +223,7 @@ so be conservative and keep to a minimum.
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See also <a HREF="#Internationalization">Internationalization</a>.
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See also <a HREF="#Internationalization">Internationalization</a>.
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</li>
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</li>
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<li>
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<li>
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<b>debug</b> - detailed information on flow of through the system.
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<b>debug</b> - detailed information on the flow through the system.
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Expect these to be written to logs only.
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Expect these to be written to logs only.
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</li>
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</li>
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<li>
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<li>
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@@ -246,7 +246,7 @@ to follow the rules.
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Since any problems that result are going to be assigned to you,
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Since any problems that result are going to be assigned to you,
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it's in your best interest to be prepared with the proactive
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it's in your best interest to be prepared with the proactive
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tools necessary to demonstrate that your component works correctly,
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tools necessary to demonstrate that your component works correctly,
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or at worst that the problem analyzed from your logs.
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or at worst that the problem can be analyzed from your logs.
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For this discussion, we must make a distinction between different types of exceptions
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For this discussion, we must make a distinction between different types of exceptions
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based on what kind of boundaries they cross:
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based on what kind of boundaries they cross:
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</p>
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</p>
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@@ -344,7 +344,7 @@ for working with NLS messages.
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</p>
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</p>
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<p>
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<p>
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NLS enabled components are particularly appreciated
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NLS enabled components are particularly appreciated
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(thats an open-source-correct term for 'required by corporate end-users' :-)
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(that's an open-source-correct term for 'required by corporate end-users' :-)
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for <strong>tooling</strong> and <strong>middleware</strong> components.
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for <strong>tooling</strong> and <strong>middleware</strong> components.
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</p>
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</p>
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<p>
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<p>
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@@ -391,7 +391,7 @@ for the following toolkits, in order of preference:
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</p>
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</p>
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<ul>
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<ul>
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<li>
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<li>
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<a href="http://jakarta.apache.org/log4j/docs/index.html">Log4J</a>
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<a href="http://logging.apache.org/log4j/docs/index.html">Log4J</a>
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</li>
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</li>
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<li>
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<li>
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JDK 1.4
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JDK 1.4
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@@ -443,13 +443,13 @@ can be configured to use different logging toolkits.
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Configuration of the behavior of the JCL ultimately depends upon the
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Configuration of the behavior of the JCL ultimately depends upon the
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logging toolkit being used.
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logging toolkit being used.
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The JCL SPI uses
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The JCL SPI uses
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<a href="http://jakarta.apache.org/log4j/docs/index.html">Log4J</a>
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<a href="http://logging.apache.org/log4j/docs/index.html">Log4J</a>
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by default if it is available (in the CLASSPATH).
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by default if it is available (in the CLASSPATH).
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</p>
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</p>
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<subsection name='Log4J'>
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<subsection name='Log4J'>
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<p>
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<p>
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As
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As
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<a href="http://jakarta.apache.org/log4j/docs/index.html">Log4J</a>
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<a href="http://logging.apache.org/log4j/docs/index.html">Log4J</a>
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is the default logger,
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is the default logger,
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a <i>few</i> details are presented herein to get the developer/integrator going.
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a <i>few</i> details are presented herein to get the developer/integrator going.
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</p>
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</p>
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@@ -513,7 +513,7 @@ while limiting console output to INFO (and higher).
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<p>
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<p>
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JCL doesn't (and cannot) impose any requirement on thread safety on the underlying implementation
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JCL doesn't (and cannot) impose any requirement on thread safety on the underlying implementation
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and thus its SPI contract doesn't guarantee thread safety.
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and thus its SPI contract doesn't guarantee thread safety.
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However, JCL can be safely used a multi-threaded environment
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However, JCL can be safely used in a multi-threaded environment
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as long as the underlying implementation is thread-safe.
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as long as the underlying implementation is thread-safe.
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</p>
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</p>
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<p>
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<p>
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Robert Burrell Donkin