[slf4j-dev] svn commit: r1192 - in slf4j/trunk: slf4j-api/src/main/java/org/slf4j slf4j-api/src/main/java/org/slf4j/helpers slf4j-nop/src/main/java/org/slf4j/impl slf4j-site/src/site/pages
ceki at slf4j.org
ceki at slf4j.org
Thu Oct 16 14:49:06 CEST 2008
Author: ceki
Date: Thu Oct 16 14:49:05 2008
New Revision: 1192
Added:
slf4j/trunk/slf4j-api/src/main/java/org/slf4j/helpers/SubstituteLoggerFactory.java
slf4j/trunk/slf4j-nop/src/main/java/org/slf4j/impl/NOPLoggerFactory.java
- copied, changed from r1190, /slf4j/trunk/slf4j-api/src/main/java/org/slf4j/helpers/NOPLoggerFactory.java
Removed:
slf4j/trunk/slf4j-api/src/main/java/org/slf4j/helpers/NOPLoggerFactory.java
Modified:
slf4j/trunk/slf4j-api/src/main/java/org/slf4j/LoggerFactory.java
slf4j/trunk/slf4j-nop/src/main/java/org/slf4j/impl/StaticLoggerBinder.java
slf4j/trunk/slf4j-site/src/site/pages/codes.html
Log:
Further refinements in relation to bug 106.
Since the logger returned by the nop factory are not functional (nop loggers),
we need to tell the user that she should not expect any logging from such loggers.
LoggerFactory will now list any nop loggers that it had to create.
Modified: slf4j/trunk/slf4j-api/src/main/java/org/slf4j/LoggerFactory.java
==============================================================================
--- slf4j/trunk/slf4j-api/src/main/java/org/slf4j/LoggerFactory.java (original)
+++ slf4j/trunk/slf4j-api/src/main/java/org/slf4j/LoggerFactory.java Thu Oct 16 14:49:05 2008
@@ -24,7 +24,10 @@
package org.slf4j;
-import org.slf4j.helpers.NOPLoggerFactory;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.slf4j.helpers.SubstituteLoggerFactory;
import org.slf4j.helpers.Util;
import org.slf4j.impl.StaticLoggerBinder;
@@ -51,6 +54,7 @@
static final String NO_STATICLOGGERBINDER_URL = "http://www.slf4j.org/codes.html#StaticLoggerBinder";
static final String NULL_LF_URL = "http://www.slf4j.org/codes.html#null_LF";
static final String VERSION_MISMATCH = "http://www.slf4j.org/codes.html#version_mismatch";
+ static final String SUBSTITUTE_LOGGER_URL = "http://www.slf4j.org/codes.html#substituteLogger";
static private final String EXPECTED_VERSION = "1.5.4-SNAPSHOT";
@@ -65,10 +69,12 @@
private final static void staticInitialize() {
try {
- // support re-entrant behavior.
+ // support re-entrant behavior.
// See also http://bugzilla.slf4j.org/show_bug.cgi?id=106
- loggerFactory = new NOPLoggerFactory();
+ List loggerNameList = new ArrayList();
+ loggerFactory = new SubstituteLoggerFactory(loggerNameList);
loggerFactory = StaticLoggerBinder.SINGLETON.getLoggerFactory();
+ emitSubstitureLoggerWarning(loggerNameList);
} catch (NoClassDefFoundError ncde) {
loggerFactory = null; // undo NOPLoggerFactory
String msg = ncde.getMessage();
@@ -88,6 +94,21 @@
}
}
+ private final static void emitSubstitureLoggerWarning(List loggerNameList) {
+ if(loggerNameList.size() == 0) {
+ return;
+ }
+ Util
+ .reportFailure("The following loggers will not work becasue they were created");
+ Util
+ .reportFailure("during the default configuration phase of the underlying logging system.");
+ Util.reportFailure("See also " + SUBSTITUTE_LOGGER_URL);
+ for (int i = 0; i < loggerNameList.size(); i++) {
+ String loggerName = (String) loggerNameList.get(i);
+ Util.reportFailure(loggerName);
+ }
+ }
+
private final static void versionSanityCheck() {
try {
String actualVer = StaticLoggerBinder.VERSION;
@@ -108,7 +129,6 @@
e.printStackTrace();
}
}
-
/**
* Return a logger named according to the name parameter using the statically
Added: slf4j/trunk/slf4j-api/src/main/java/org/slf4j/helpers/SubstituteLoggerFactory.java
==============================================================================
--- (empty file)
+++ slf4j/trunk/slf4j-api/src/main/java/org/slf4j/helpers/SubstituteLoggerFactory.java Thu Oct 16 14:49:05 2008
@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2004-2005 SLF4J.ORG
+ * Copyright (c) 2004-2005 QOS.ch
+ *
+ * All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, and/or sell copies of the Software, and to permit persons
+ * to whom the Software is furnished to do so, provided that the above
+ * copyright notice(s) and this permission notice appear in all copies of
+ * the Software and that both the above copyright notice(s) and this
+ * permission notice appear in supporting documentation.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+ * OF THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+ * HOLDERS INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY
+ * SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER
+ * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
+ * CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Except as contained in this notice, the name of a copyright holder
+ * shall not be used in advertising or otherwise to promote the sale, use
+ * or other dealings in this Software without prior written authorization
+ * of the copyright holder.
+ *
+ */
+
+package org.slf4j.helpers;
+
+import java.util.List;
+
+import org.slf4j.ILoggerFactory;
+import org.slf4j.Logger;
+
+
+/**
+ * SubstituteLoggerFactory is an trivial implementation of {@link
+ * ILoggerFactory} which always returns the unique instance of
+ * NOPLogger.
+ *
+ * <p>It used as a temporary substitute for the real ILoggerFactory
+ * during its auto-configuration which may re-enter LoggerFactory
+ * to obtain logger instances. See also
+ * http://bugzilla.slf4j.org/show_bug.cgi?id=106
+ *
+ * @author Ceki Gülcü
+ */
+public class SubstituteLoggerFactory implements ILoggerFactory {
+
+ // keep a record of requested logger names
+ final List loggerNameList;
+
+ public SubstituteLoggerFactory(List loggerNameList) {
+ this.loggerNameList = loggerNameList;
+ }
+
+ public Logger getLogger(String name) {
+ loggerNameList.add(name);
+ return NOPLogger.NOP_LOGGER;
+ }
+}
Copied: slf4j/trunk/slf4j-nop/src/main/java/org/slf4j/impl/NOPLoggerFactory.java (from r1190, /slf4j/trunk/slf4j-api/src/main/java/org/slf4j/helpers/NOPLoggerFactory.java)
==============================================================================
--- /slf4j/trunk/slf4j-api/src/main/java/org/slf4j/helpers/NOPLoggerFactory.java (original)
+++ slf4j/trunk/slf4j-nop/src/main/java/org/slf4j/impl/NOPLoggerFactory.java Thu Oct 16 14:49:05 2008
@@ -31,7 +31,7 @@
*
*/
-package org.slf4j.helpers;
+package org.slf4j.impl;
import org.slf4j.ILoggerFactory;
import org.slf4j.Logger;
Modified: slf4j/trunk/slf4j-nop/src/main/java/org/slf4j/impl/StaticLoggerBinder.java
==============================================================================
--- slf4j/trunk/slf4j-nop/src/main/java/org/slf4j/impl/StaticLoggerBinder.java (original)
+++ slf4j/trunk/slf4j-nop/src/main/java/org/slf4j/impl/StaticLoggerBinder.java Thu Oct 16 14:49:05 2008
@@ -35,7 +35,6 @@
import org.slf4j.ILoggerFactory;
import org.slf4j.LoggerFactory;
-import org.slf4j.helpers.NOPLoggerFactory;
import org.slf4j.spi.LoggerFactoryBinder;
/**
Modified: slf4j/trunk/slf4j-site/src/site/pages/codes.html
==============================================================================
--- slf4j/trunk/slf4j-site/src/site/pages/codes.html (original)
+++ slf4j/trunk/slf4j-site/src/site/pages/codes.html Thu Oct 16 14:49:05 2008
@@ -177,6 +177,47 @@
mismatch problem, it emits a warning about the said mismatch.
</p>
+
+ <h3><a name="substituteLogger" href="#substituteLogger">Substiture
+ loggers were created during the default configuration phase of the
+ underlying logging system</a></h3>
+
+ <p>Highly configurable logging systems such as logback and log4j may
+ create components which invoke loggers during their own
+ initialization. See issue <a
+ href="http://jira.qos.ch/browse/LBCORE-47">lbcore-47</a> for a
+ typical occurence. However, since the binding process with SLF4J has
+ not yet completed (because the underlying logging system was not yet
+ completely loaded into memory), it is not possible to honor such
+ logger creation requests, resulting in a
+ <code>NullPointerException</code>.</p>
+
+ <p>To avoid this chicken-and-egg problem, SLF4J substitutes a
+ no-operation logger factory during this initialization
+ phase. However, the loggers returned during this phase by the
+ substitute logger factory are not operational. They are nop
+ implementations.
+ </p>
+
+ <p>If any substitute logger had to be created, SLF4J will emit a
+ warning listing such nop loggers. This warning is intended to let
+ you know that you should not expect any logging output from these
+ loggers.
+ </p>
+
+ <p>The only way to obtain output from the listed loggers, is to
+ isolate the components invoking these loggers and to exlude them
+ from the default configuration. Both logback and log4j allow
+ multi-step configuration. It follows that the problematic components
+ should be configured in a second step separate from default
+ configuration.
+ </p>
+
+ <p>If you are not interested in the output from any of the
+ substiture loggers, then no action is required on your part.</p>
+
+
+
</div>
</body>
</html>
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