org.slf4j.LoggerFactory Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
/**
* Copyright (c) 2004-2011 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, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* 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. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*/
package org.slf4j;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
import java.util.concurrent.LinkedBlockingQueue;
import org.slf4j.event.SubstituteLoggingEvent;
import org.slf4j.helpers.NOPLoggerFactory;
import org.slf4j.helpers.SubstituteLogger;
import org.slf4j.helpers.SubstituteLoggerFactory;
import org.slf4j.helpers.Util;
import org.slf4j.impl.StaticLoggerBinder;
/**
* The LoggerFactory is a utility class producing Loggers for
* various logging APIs, most notably for log4j, logback and JDK 1.4 logging.
* Other implementations such as {@link org.slf4j.impl.NOPLogger NOPLogger} and
* {@link org.slf4j.impl.SimpleLogger SimpleLogger} are also supported.
*
*
* LoggerFactory is essentially a wrapper around an
* {@link ILoggerFactory} instance bound with LoggerFactory at
* compile time.
*
*
* Please note that all methods in LoggerFactory are static.
*
*
* @author Alexander Dorokhine
* @author Robert Elliot
* @author Ceki Gülcü
*
*/
public final class LoggerFactory {
static final String CODES_PREFIX = "http://www.slf4j.org/codes.html";
static final String NO_STATICLOGGERBINDER_URL = CODES_PREFIX + "#StaticLoggerBinder";
static final String MULTIPLE_BINDINGS_URL = CODES_PREFIX + "#multiple_bindings";
static final String NULL_LF_URL = CODES_PREFIX + "#null_LF";
static final String VERSION_MISMATCH = CODES_PREFIX + "#version_mismatch";
static final String SUBSTITUTE_LOGGER_URL = CODES_PREFIX + "#substituteLogger";
static final String LOGGER_NAME_MISMATCH_URL = CODES_PREFIX + "#loggerNameMismatch";
static final String REPLAY_URL = CODES_PREFIX + "#replay";
static final String UNSUCCESSFUL_INIT_URL = CODES_PREFIX + "#unsuccessfulInit";
static final String UNSUCCESSFUL_INIT_MSG = "org.slf4j.LoggerFactory in failed state. Original exception was thrown EARLIER. See also " + UNSUCCESSFUL_INIT_URL;
static final int UNINITIALIZED = 0;
static final int ONGOING_INITIALIZATION = 1;
static final int FAILED_INITIALIZATION = 2;
static final int SUCCESSFUL_INITIALIZATION = 3;
static final int NOP_FALLBACK_INITIALIZATION = 4;
static volatile int INITIALIZATION_STATE = UNINITIALIZED;
static final SubstituteLoggerFactory SUBST_FACTORY = new SubstituteLoggerFactory();
static final NOPLoggerFactory NOP_FALLBACK_FACTORY = new NOPLoggerFactory();
// Support for detecting mismatched logger names.
static final String DETECT_LOGGER_NAME_MISMATCH_PROPERTY = "slf4j.detectLoggerNameMismatch";
static final String JAVA_VENDOR_PROPERTY = "java.vendor.url";
static boolean DETECT_LOGGER_NAME_MISMATCH = Util.safeGetBooleanSystemProperty(DETECT_LOGGER_NAME_MISMATCH_PROPERTY);
/**
* It is LoggerFactory's responsibility to track version changes and manage
* the compatibility list.
*
*
* It is assumed that all versions in the 1.6 are mutually compatible.
*/
static private final String[] API_COMPATIBILITY_LIST = new String[] { "1.6", "1.7" };
// private constructor prevents instantiation
private LoggerFactory() {
}
/**
* Force LoggerFactory to consider itself uninitialized.
*
*
* This method is intended to be called by classes (in the same package) for
* testing purposes. This method is internal. It can be modified, renamed or
* removed at any time without notice.
*
*
* You are strongly discouraged from calling this method in production code.
*/
static void reset() {
INITIALIZATION_STATE = UNINITIALIZED;
}
private final static void performInitialization() {
bind();
if (INITIALIZATION_STATE == SUCCESSFUL_INITIALIZATION) {
versionSanityCheck();
}
}
private static boolean messageContainsOrgSlf4jImplStaticLoggerBinder(String msg) {
if (msg == null)
return false;
if (msg.contains("org/slf4j/impl/StaticLoggerBinder"))
return true;
if (msg.contains("org.slf4j.impl.StaticLoggerBinder"))
return true;
return false;
}
private final static void bind() {
try {
Set staticLoggerBinderPathSet = null;
// skip check under android, see also
// http://jira.qos.ch/browse/SLF4J-328
if (!isAndroid()) {
staticLoggerBinderPathSet = findPossibleStaticLoggerBinderPathSet();
reportMultipleBindingAmbiguity(staticLoggerBinderPathSet);
}
// the next line does the binding
StaticLoggerBinder.getSingleton();
INITIALIZATION_STATE = SUCCESSFUL_INITIALIZATION;
reportActualBinding(staticLoggerBinderPathSet);
} catch (NoClassDefFoundError ncde) {
String msg = ncde.getMessage();
if (messageContainsOrgSlf4jImplStaticLoggerBinder(msg)) {
INITIALIZATION_STATE = NOP_FALLBACK_INITIALIZATION;
Util.report("Failed to load class \"org.slf4j.impl.StaticLoggerBinder\".");
Util.report("Defaulting to no-operation (NOP) logger implementation");
Util.report("See " + NO_STATICLOGGERBINDER_URL + " for further details.");
} else {
failedBinding(ncde);
throw ncde;
}
} catch (java.lang.NoSuchMethodError nsme) {
String msg = nsme.getMessage();
if (msg != null && msg.contains("org.slf4j.impl.StaticLoggerBinder.getSingleton()")) {
INITIALIZATION_STATE = FAILED_INITIALIZATION;
Util.report("slf4j-api 1.6.x (or later) is incompatible with this binding.");
Util.report("Your binding is version 1.5.5 or earlier.");
Util.report("Upgrade your binding to version 1.6.x.");
}
throw nsme;
} catch (Exception e) {
failedBinding(e);
throw new IllegalStateException("Unexpected initialization failure", e);
} finally {
postBindCleanUp();
}
}
private static void postBindCleanUp() {
fixSubstituteLoggers();
replayEvents();
// release all resources in SUBST_FACTORY
SUBST_FACTORY.clear();
}
private static void fixSubstituteLoggers() {
synchronized (SUBST_FACTORY) {
SUBST_FACTORY.postInitialization();
for (SubstituteLogger substLogger : SUBST_FACTORY.getLoggers()) {
Logger logger = getLogger(substLogger.getName());
substLogger.setDelegate(logger);
}
}
}
static void failedBinding(Throwable t) {
INITIALIZATION_STATE = FAILED_INITIALIZATION;
Util.report("Failed to instantiate SLF4J LoggerFactory", t);
}
private static void replayEvents() {
final LinkedBlockingQueue queue = SUBST_FACTORY.getEventQueue();
final int queueSize = queue.size();
int count = 0;
final int maxDrain = 128;
List eventList = new ArrayList(maxDrain);
while (true) {
int numDrained = queue.drainTo(eventList, maxDrain);
if (numDrained == 0)
break;
for (SubstituteLoggingEvent event : eventList) {
replaySingleEvent(event);
if (count++ == 0)
emitReplayOrSubstituionWarning(event, queueSize);
}
eventList.clear();
}
}
private static void emitReplayOrSubstituionWarning(SubstituteLoggingEvent event, int queueSize) {
if (event.getLogger().isDelegateEventAware()) {
emitReplayWarning(queueSize);
} else if (event.getLogger().isDelegateNOP()) {
// nothing to do
} else {
emitSubstitutionWarning();
}
}
private static void replaySingleEvent(SubstituteLoggingEvent event) {
if (event == null)
return;
SubstituteLogger substLogger = event.getLogger();
String loggerName = substLogger.getName();
if (substLogger.isDelegateNull()) {
throw new IllegalStateException("Delegate logger cannot be null at this state.");
}
if (substLogger.isDelegateNOP()) {
// nothing to do
} else if (substLogger.isDelegateEventAware()) {
substLogger.log(event);
} else {
Util.report(loggerName);
}
}
private static void emitSubstitutionWarning() {
Util.report("The following set of substitute loggers may have been accessed");
Util.report("during the initialization phase. Logging calls during this");
Util.report("phase were not honored. However, subsequent logging calls to these");
Util.report("loggers will work as normally expected.");
Util.report("See also " + SUBSTITUTE_LOGGER_URL);
}
private static void emitReplayWarning(int eventCount) {
Util.report("A number (" + eventCount + ") of logging calls during the initialization phase have been intercepted and are");
Util.report("now being replayed. These are subject to the filtering rules of the underlying logging system.");
Util.report("See also " + REPLAY_URL);
}
private final static void versionSanityCheck() {
try {
String requested = StaticLoggerBinder.REQUESTED_API_VERSION;
boolean match = false;
for (String aAPI_COMPATIBILITY_LIST : API_COMPATIBILITY_LIST) {
if (requested.startsWith(aAPI_COMPATIBILITY_LIST)) {
match = true;
}
}
if (!match) {
Util.report("The requested version " + requested + " by your slf4j binding is not compatible with "
+ Arrays.asList(API_COMPATIBILITY_LIST).toString());
Util.report("See " + VERSION_MISMATCH + " for further details.");
}
} catch (java.lang.NoSuchFieldError nsfe) {
// given our large user base and SLF4J's commitment to backward
// compatibility, we cannot cry here. Only for implementations
// which willingly declare a REQUESTED_API_VERSION field do we
// emit compatibility warnings.
} catch (Throwable e) {
// we should never reach here
Util.report("Unexpected problem occured during version sanity check", e);
}
}
// We need to use the name of the StaticLoggerBinder class, but we can't
// reference
// the class itself.
private static String STATIC_LOGGER_BINDER_PATH = "org/slf4j/impl/StaticLoggerBinder.class";
static Set findPossibleStaticLoggerBinderPathSet() {
// use Set instead of list in order to deal with bug #138
// LinkedHashSet appropriate here because it preserves insertion order
// during iteration
Set staticLoggerBinderPathSet = new LinkedHashSet();
try {
ClassLoader loggerFactoryClassLoader = LoggerFactory.class.getClassLoader();
Enumeration paths;
if (loggerFactoryClassLoader == null) {
paths = ClassLoader.getSystemResources(STATIC_LOGGER_BINDER_PATH);
} else {
paths = loggerFactoryClassLoader.getResources(STATIC_LOGGER_BINDER_PATH);
}
while (paths.hasMoreElements()) {
URL path = paths.nextElement();
staticLoggerBinderPathSet.add(path);
}
} catch (IOException ioe) {
Util.report("Error getting resources from path", ioe);
}
return staticLoggerBinderPathSet;
}
private static boolean isAmbiguousStaticLoggerBinderPathSet(Set binderPathSet) {
return binderPathSet.size() > 1;
}
/**
* Prints a warning message on the console if multiple bindings were found
* on the class path. No reporting is done otherwise.
*
*/
private static void reportMultipleBindingAmbiguity(Set binderPathSet) {
if (isAmbiguousStaticLoggerBinderPathSet(binderPathSet)) {
Util.report("Class path contains multiple SLF4J bindings.");
for (URL path : binderPathSet) {
Util.report("Found binding in [" + path + "]");
}
Util.report("See " + MULTIPLE_BINDINGS_URL + " for an explanation.");
}
}
private static boolean isAndroid() {
String vendor = Util.safeGetSystemProperty(JAVA_VENDOR_PROPERTY);
if (vendor == null)
return false;
return vendor.toLowerCase().contains("android");
}
private static void reportActualBinding(Set binderPathSet) {
// binderPathSet can be null under Android
if (binderPathSet != null && isAmbiguousStaticLoggerBinderPathSet(binderPathSet)) {
Util.report("Actual binding is of type [" + StaticLoggerBinder.getSingleton().getLoggerFactoryClassStr() + "]");
}
}
/**
* Return a logger named according to the name parameter using the
* statically bound {@link ILoggerFactory} instance.
*
* @param name
* The name of the logger.
* @return logger
*/
public static Logger getLogger(String name) {
ILoggerFactory iLoggerFactory = getILoggerFactory();
return iLoggerFactory.getLogger(name);
}
/**
* Return a logger named corresponding to the class passed as parameter,
* using the statically bound {@link ILoggerFactory} instance.
*
*
* In case the the clazz parameter differs from the name of the
* caller as computed internally by SLF4J, a logger name mismatch warning
* will be printed but only if the
* slf4j.detectLoggerNameMismatch system property is set to
* true. By default, this property is not set and no warnings will be
* printed even in case of a logger name mismatch.
*
* @param clazz
* the returned logger will be named after clazz
* @return logger
*
*
* @see Detected
* logger name mismatch
*/
public static Logger getLogger(Class clazz) {
Logger logger = getLogger(clazz.getName());
if (DETECT_LOGGER_NAME_MISMATCH) {
Class autoComputedCallingClass = Util.getCallingClass();
if (autoComputedCallingClass != null && nonMatchingClasses(clazz, autoComputedCallingClass)) {
Util.report(String.format("Detected logger name mismatch. Given name: \"%s\"; computed name: \"%s\".", logger.getName(),
autoComputedCallingClass.getName()));
Util.report("See " + LOGGER_NAME_MISMATCH_URL + " for an explanation");
}
}
return logger;
}
private static boolean nonMatchingClasses(Class clazz, Class autoComputedCallingClass) {
return !autoComputedCallingClass.isAssignableFrom(clazz);
}
/**
* Return the {@link ILoggerFactory} instance in use.
*
*
* ILoggerFactory instance is bound with this class at compile time.
*
* @return the ILoggerFactory instance in use
*/
public static ILoggerFactory getILoggerFactory() {
if (INITIALIZATION_STATE == UNINITIALIZED) {
synchronized (LoggerFactory.class) {
if (INITIALIZATION_STATE == UNINITIALIZED) {
INITIALIZATION_STATE = ONGOING_INITIALIZATION;
performInitialization();
}
}
}
switch (INITIALIZATION_STATE) {
case SUCCESSFUL_INITIALIZATION:
return StaticLoggerBinder.getSingleton().getLoggerFactory();
case NOP_FALLBACK_INITIALIZATION:
return NOP_FALLBACK_FACTORY;
case FAILED_INITIALIZATION:
throw new IllegalStateException(UNSUCCESSFUL_INIT_MSG);
case ONGOING_INITIALIZATION:
// support re-entrant behavior.
// See also http://jira.qos.ch/browse/SLF4J-97
return SUBST_FACTORY;
}
throw new IllegalStateException("Unreachable code");
}
}