Author: markt
Date: Mon May 26 15:16:45 2014
New Revision: 1597602
URL: http://svn.apache.org/r1597602
Log:
Implement second part of pull request from Greg Wilkins to make Jasper more
independent from Tomcat.
Add ServiceLoader based discovery support to the JULI LogFactory
Modified:
tomcat/trunk/java/org/apache/juli/logging/LogFactory.java
tomcat/trunk/webapps/docs/changelog.xml
Modified: tomcat/trunk/java/org/apache/juli/logging/LogFactory.java
URL:
http://svn.apache.org/viewvc/tomcat/trunk/java/org/apache/juli/logging/LogFactory.java?rev=1597602&r1=1597601&r2=1597602&view=diff
==============================================================================
--- tomcat/trunk/java/org/apache/juli/logging/LogFactory.java (original)
+++ tomcat/trunk/java/org/apache/juli/logging/LogFactory.java Mon May 26
15:16:45 2014
@@ -16,33 +16,34 @@
*/
package org.apache.juli.logging;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.util.ServiceLoader;
import java.util.logging.LogManager;
/**
- * Modified LogFactory: removed all discovery, hardcode a specific
implementation
- * If you like a different logging implementation - use either the
discovery-based
- * commons-logging, or better - another implementation hardcoded to your
favourite
- * logging impl.
- *
- * Why ? Each application and deployment can choose a logging implementation -
- * that involves configuration, installing the logger jar and optional
plugins, etc.
- * As part of this process - they can as well install the commons-logging
implementation
- * that corresponds to their logger of choice. This completely avoids any
discovery
- * problem, while still allowing the user to switch.
- *
- * Note that this implementation is not just a wrapper around JDK logging (
like
- * the original commons-logging impl ). It adds 2 features - a simpler
configuration
- * ( which is in fact a subset of log4j.properties ) and a formatter that is
- * less ugly.
- *
- * The removal of 'abstract' preserves binary backward compatibility. It is
possible
- * to preserve the abstract - and introduce another ( hardcoded ) factory -
but I
- * see no benefit.
- *
- * Since this class is not intended to be extended - and provides
- * no plugin for other LogFactory implementation - all protected methods are
removed.
- * This can be changed - but again, there is little value in keeping dead code.
- * Just take a quick look at the removed code ( and it's complexity)
+ * This is a modified LogFactory that uses a simple {@link ServiceLoader} based
+ * discovery mechanism with a default of using JDK based logging. An
+ * implementation that uses the full Commons Logging discovery mechanism is
+ * available as part of the Tomcat extras download.
+ *
+ * Why? It is an attempt to strike a balance between simpler code (no
discovery)
+ * and providing flexibility - particularly for those projects that embed
Tomcat
+ * or some of Tomcat's components - is an alternative logging
+ * implementationnis desired.
+ *
+ * Note that this implementation is not just a wrapper around JDK logging (like
+ * the original commons-logging impl). It adds 2 features - a simpler
+ * configuration (which is in fact a subset of log4j.properties) and a
+ * formatter that is less ugly.
+ *
+ * The removal of 'abstract' preserves binary backward compatibility. It is
+ * possible to preserve the abstract - and introduce another (hardcoded)
factory
+ * - but I see no benefit.
+ *
+ * Since this class is not intended to be extended - all protected methods are
+ * removed. This can be changed - but again, there is little value in keeping
+ * dead code. Just take a quick look at the removed code ( and it's
complexity).
*
* --------------
*
@@ -64,11 +65,26 @@ public class LogFactory {
private static final LogFactory singleton = new LogFactory();
+ private final Constructor<? extends Log> discoveredLogConstructor;
/**
- * Protected constructor that is not available for public use.
+ * Private constructor that is not available for public use.
*/
private LogFactory() {
+ // Look via a ServiceLoader for a Log implementation that has a
+ // constructor taking the String name.
+ ServiceLoader<Log> logLoader = ServiceLoader.load(Log.class);
+ Constructor<? extends Log> m=null;
+ for (Log log: logLoader) {
+ Class<? extends Log> c=log.getClass();
+ try {
+ m=c.getConstructor(String.class);
+ }
+ catch (NoSuchMethodException | SecurityException e) {
+ throw new Error(e);
+ }
+ }
+ discoveredLogConstructor=m;
}
@@ -93,9 +109,17 @@ public class LogFactory {
* @exception LogConfigurationException if a suitable <code>Log</code>
* instance cannot be returned
*/
- public Log getInstance(String name)
- throws LogConfigurationException {
- return DirectJDKLog.getInstance(name);
+ public Log getInstance(String name) throws LogConfigurationException {
+ if (discoveredLogConstructor == null) {
+ return DirectJDKLog.getInstance(name);
+ }
+
+ try {
+ return discoveredLogConstructor.newInstance(name);
+ } catch (InstantiationException | IllegalAccessException |
IllegalArgumentException |
+ InvocationTargetException e) {
+ throw new RuntimeException(e);
+ }
}
@@ -108,8 +132,7 @@ public class LogFactory {
* @exception LogConfigurationException if a suitable <code>Log</code>
* instance cannot be returned
*/
- public Log getInstance(Class<?> clazz)
- throws LogConfigurationException {
+ public Log getInstance(Class<?> clazz) throws LogConfigurationException {
return getInstance( clazz.getName());
}
Modified: tomcat/trunk/webapps/docs/changelog.xml
URL:
http://svn.apache.org/viewvc/tomcat/trunk/webapps/docs/changelog.xml?rev=1597602&r1=1597601&r2=1597602&view=diff
==============================================================================
--- tomcat/trunk/webapps/docs/changelog.xml (original)
+++ tomcat/trunk/webapps/docs/changelog.xml Mon May 26 15:16:45 2014
@@ -105,6 +105,12 @@
<code>=</code> character leading to a mis-match between the cookie the
server set and the cookie returned by the browser. (jboynes/markt)
</fix>
+ <add>
+ Add a simple <code>ServiceLoader</code> based discovery mechanism to
the
+ JULI <code>LogFactory</code> to make it easier to use JULI and Tomcat
+ components that depend on JULI (such as Jasper) independently from
+ Tomcat. Patch provided by Greg Wilkins. (markt)
+ </add>
</changelog>
</subsection>
<subsection name="Coyote">
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