上篇博客介绍了LoggerContext怎么生成Logger，Logger是logback的核心类，也是所有日志框架的核心类。这篇博客详细介绍一下Logger的各字段和方法，重点介绍Logger类是怎样记录日志的
Logger类实现了slf4j框架定义的Logger接口，然后这个类和LoggerContext是互相引用的（因为Logger需要依赖LoggerContext的TurboFilter等组件）。并且Logger实现了AppenderAttachable接口，它实现该接口的方式，是持有AppenderAttachableImpl类，然后委托该类来实现AppenderAttachable接口定义的方法，这里用到了代理模式，是一个比较精巧的设计
看到了Logger类的全景图，接下来我们逐一介绍Logger类中的各个字段，最后重点介绍Logger类是怎样记录日志的
首先看看Logger的字段
public final class Logger implements org.slf4j.Logger, LocationAwareLogger, AppenderAttachable<ILoggingEvent>, Serializable { private static final long serialVersionUID = 5454405123156820674L; // 8745934908040027998L; /** * 此类的完全限定名称。用于收集呼叫者信息。 */ public static final String FQCN = ch.qos.logback.classic.Logger.class.getName(); /** * Logger的名称 */ private String name; // 此记录器的指定 levelInt。 可以为空。 transient private Level level; // 有效的 levelInt 是分配的 levelInt，如果为 null，则从父级继承 levelInt。 transient private int effectiveLevelInt; /** * 此类别的父级。 所有类别至少有一个祖先，即根类别。 */ transient private Logger parent; /** * 这个记录器的孩子。 一个记录器可能有零个或多个子节点。 */ transient private List<Logger> childrenList; /** * It is assumed that once the 'aai' variable is set to a non-null value, it * will never be reset to null. it is further assumed that only place where * the 'aai'ariable is set is within the addAppender method. This method is * synchronized on 'this' (Logger) protecting against simultaneous * re-configuration of this logger (a very unlikely scenario). * * <p> * It is further assumed that the AppenderAttachableImpl is responsible for * its internal synchronization and thread safety. Thus, we can get away with * *not* synchronizing on the 'aai' (check null/ read) because * <p> * 1) the 'aai' variable is immutable once set to non-null * <p> * 2) 'aai' is getAndSet only within addAppender which is synchronized * <p> * 3) all the other methods check whether 'aai' is null * <p> * 4) AppenderAttachableImpl is thread safe */ transient private AppenderAttachableImpl<ILoggingEvent> aai; /** * Additivity is set to true by default, that is children inherit the * appenders of their ancestors by default. If this variable is set to * <code>false</code> then the appenders located in the ancestors of this * logger will not be used. However, the children of this logger will inherit * its appenders, unless the children have their additivity flag set to * <code>false</code> too. See the user manual for more details. */ transient private boolean additive = true; final transient LoggerContext loggerContext; Logger(String name, Logger parent, LoggerContext loggerContext) { this.name = name; this.parent = parent; this.loggerContext = loggerContext; }
1、name是Logger的名称
2、level是该Logger的分配级别，当配置文件中没有配置时，这个分配级别可以为null
3、effectiveLevelInt是该Logger的生效级别，会从父Logger继承得到
4、parent和childrenList是这个Logger的父Logger和子Logger，体现了logback的Logger层次结构
5、aai上面已经说到了，Logger是委托这个类实现AppenderAttachable接口，也是委托这个类来调用Appender组件来实际记录日志，所以这个字段是最关键的
6、additive是这个类的Appender叠加性，具体看我的另一篇博客。该字段也是在配置文件中配置的，默认为true
介绍完了字段，可以看到Logger的设计还是相当清晰易懂的， 接下来逐一看看Logger中的方法，getter和setter方法就不废话了
private boolean isRootLogger() { // only the root logger has a null parent return parent == null; }
这个方法用来判断一个Logger是否是根Logger
Logger getChildByName(final String childName) { if (childrenList == null) { return null; } else { int len = this.childrenList.size(); for (int i = 0; i < len; i++) { final Logger childLogger_i = (Logger) childrenList.get(i); final String childName_i = childLogger_i.getName(); if (childName.equals(childName_i)) { return childLogger_i; } } // no child found return null; } }
这个方法用来得到子Logger，是在LoggerContext的getLogger()方法里调用的，在上一篇博客里已经介绍过了
public synchronized void setLevel(Level newLevel) { if (level == newLevel) { // nothing to do; return; } if (newLevel == null && isRootLogger()) { throw new IllegalArgumentException("The level of the root logger cannot be set to null"); } level = newLevel; if (newLevel == null) { effectiveLevelInt = parent.effectiveLevelInt; newLevel = parent.getEffectiveLevel(); } else { effectiveLevelInt = newLevel.levelInt; } if (childrenList != null) { int len = childrenList.size(); for (int i = 0; i < len; i++) { Logger child = (Logger) childrenList.get(i); // tell child to handle parent levelInt change child.handleParentLevelChange(effectiveLevelInt); } } // inform listeners loggerContext.fireOnLevelChange(this, newLevel); } /** * This method is invoked by parent logger to let this logger know that the * prent's levelInt changed. * * @param newParentLevelInt */ private synchronized void handleParentLevelChange(int newParentLevelInt) { // changes in the parent levelInt affect children only if their levelInt is // null if (level == null) { effectiveLevelInt = newParentLevelInt; // propagate the parent levelInt change to this logger's children if (childrenList != null) { int len = childrenList.size(); for (int i = 0; i < len; i++) { Logger child = (Logger) childrenList.get(i); child.handleParentLevelChange(newParentLevelInt); } } } }
这2个方法是用来改变Logger的生效级别，并且连带改变子Logger的生效级别
/** * The default size of child list arrays. The JDK 1.5 default is 10. We use a * smaller value to save a little space. */ Logger createChildByName(final String childName) { int i_index = LoggerNameUtil.getSeparatorIndexOf(childName, this.name.length() + 1); if (i_index != -1) { throw new IllegalArgumentException("For logger [" + this.name + "] child name [" + childName + " passed as parameter, may not include '.' after index" + (this.name.length() + 1)); } if (childrenList == null) { childrenList = new CopyOnWriteArrayList<Logger>(); } Logger childLogger; childLogger = new Logger(childName, this, this.loggerContext); childrenList.add(childLogger); childLogger.effectiveLevelInt = this.effectiveLevelInt; return childLogger; }
这个方法是用来创建子Logger的，并且会设置Logger的父子关系，也是在LoggerContext的getLogger()方法里调用的
接下来就重点介绍Logger组件怎么记录日志了，slf4j定义了Logger接口记录日志的方法是info()、warn()、debug()等，这些方法只是入口，logback是这样实现这些方法的
public void info(String msg) { filterAndLog_0_Or3Plus(FQCN, null, Level.INFO, msg, null, null); }
当客户端代码调用Logger.info()时，实际上会进入filterAndLog_0_Or3Plus方法，Logger类中还有很多名字很相似的方法，比如filterAndLog_1、filterAndLog_2。据作者自己说，之所以定义这一系列的方法，是为了提高logback的性能
/** * The next methods are not merged into one because of the time we gain by not * creating a new Object[] with the params. This reduces the cost of not * logging by about 20 nanoseconds.下一个方法不会合并为一个方法，因为我们通过不使用参数创建新的 Object[] 获得了时间。 这将不记录的成本降低了大约 20 纳秒。 */ private void filterAndLog_0_Or3Plus(final String localFQCN, final Marker marker, final Level level, final String msg, final Object[] params, final Throwable t) { final FilterReply decision = loggerContext.getTurboFilterChainDecision_0_3OrMore(marker, this, level, msg, params, t); if (decision == FilterReply.NEUTRAL) { if (effectiveLevelInt > level.levelInt) { return; } } else if (decision == FilterReply.DENY) { return; } buildLoggingEventAndAppend(localFQCN, marker, level, msg, params, t); }
该方法首先要请求TurboFilter来判断是否允许记录这次日志信息。TurboFilter是快速筛选的组件，筛选发生在LoggingEvent创建之前，这种设计也是为了提高性能
如果经过过滤，确定要记录这条日志信息，则进入buildLoggingEventAndAppend方法
private void buildLoggingEventAndAppend(final String localFQCN, final Marker marker, final Level level, final String msg, final Object[] params, final Throwable t) { LoggingEvent le = new LoggingEvent(localFQCN, this, level, msg, t, params); le.setMarker(marker); callAppenders(le); }
在这个方法里，首先创建了LoggingEvent对象，然后调用callAppenders()方法，要求该Logger关联的所有Appenders来记录日志
LoggingEvent对象是承载了日志信息的类，最后输出的日志信息，就来源于这个事件对象
/** * Invoke all the appenders of this logger. * * @param event * The event to log */ public void callAppenders(ILoggingEvent event) { int writes = 0; for (Logger l = this; l != null; l = l.parent) { writes += l.appendLoopOnAppenders(event); if (!l.additive) { break; } } // No appenders in hierarchy if (writes == 0) { loggerContext.noAppenderDefinedWarning(this); } }
经过前面的Filter过滤、日志级别匹配、创建LoggerEvent对象，终于进入了记录日志的方法。该方法会调用此Logger关联的所有Appender，而且还会调用所有父Logger关联的Appender，直到遇到父Logger的additive属性设置为false为止，这也是为什么如果子Logger和父Logger都关联了同样的Appender，则日志信息会重复记录的原因
继续看下来
private int appendLoopOnAppenders(ILoggingEvent event) { if (aai != null) { return aai.appendLoopOnAppenders(event); } else { return 0; } }
实际上调用的AppenderAttachableImpl的appendLoopOnAppenders()方法
/** * Call the <code>doAppend</code> method on all attached appenders. */ public int appendLoopOnAppenders(E e) { int size = 0; final Appender<E>[] appenderArray = appenderList.asTypedArray(); final int len = appenderArray.length; for (int i = 0; i < len; i++) { appenderArray[i].doAppend(e); size++; } return size; }
到这里，为了记录一条日志信息，长长的调用链终于告一段落了，通过调用Appender的doAppend(LoggingEvent e)方法，委托Appender来最终记录日志（其实Appender记录日志信息也是委托其他的类来完成的， 在后面的博客中再介绍）
总结：
Logger类中定义的字段和方法，是出于以下目的：
1、持有LoggerContext，是为了使用TurboFilter来进行快速过滤
2、定义parent和childList，用于实现父子Logger的树形结构
3、定义createChildByName()、getChildByName()方法，是供LoggerContext创建Logger
4、定义level、effectiveLevelInt，是为了判定日志级别是否足够
5、最后，filterAndLog()、buildLoggingEventAndAppend()、callAppenders()、appendLoopOnAppenders()方法，是Logger类的核心方法，一步步地委托AppenderAttachableImpl类来实际记录日志
完整代码如下：
public final class Logger implements org.slf4j.Logger, LocationAwareLogger, AppenderAttachable<ILoggingEvent>, Serializable { private static final long serialVersionUID = 5454405123156820674L; // 8745934908040027998L; /** * The fully qualified name of this class. Used in gathering caller * information. */ public static final String FQCN = ch.qos.logback.classic.Logger.class.getName(); /** * The name of this logger */ private String name; // The assigned levelInt of this logger. Can be null. transient private Level level; // The effective levelInt is the assigned levelInt and if null, a levelInt is // inherited form a parent. transient private int effectiveLevelInt; /** * The parent of this category. All categories have at least one ancestor * which is the root category. */ transient private Logger parent; /** * The children of this logger. A logger may have zero or more children. */ transient private List<Logger> childrenList; /** * It is assumed that once the 'aai' variable is set to a non-null value, it * will never be reset to null. it is further assumed that only place where * the 'aai'ariable is set is within the addAppender method. This method is * synchronized on 'this' (Logger) protecting against simultaneous * re-configuration of this logger (a very unlikely scenario). * * <p> * It is further assumed that the AppenderAttachableImpl is responsible for * its internal synchronization and thread safety. Thus, we can get away with * *not* synchronizing on the 'aai' (check null/ read) because * <p> * 1) the 'aai' variable is immutable once set to non-null * <p> * 2) 'aai' is getAndSet only within addAppender which is synchronized * <p> * 3) all the other methods check whether 'aai' is null * <p> * 4) AppenderAttachableImpl is thread safe */ transient private AppenderAttachableImpl<ILoggingEvent> aai; /** * Additivity is set to true by default, that is children inherit the * appenders of their ancestors by default. If this variable is set to * <code>false</code> then the appenders located in the ancestors of this * logger will not be used. However, the children of this logger will inherit * its appenders, unless the children have their additivity flag set to * <code>false</code> too. See the user manual for more details. */ transient private boolean additive = true; final transient LoggerContext loggerContext; Logger(String name, Logger parent, LoggerContext loggerContext) { this.name = name; this.parent = parent; this.loggerContext = loggerContext; } public Level getEffectiveLevel() { return Level.toLevel(effectiveLevelInt); } int getEffectiveLevelInt() { return effectiveLevelInt; } public Level getLevel() { return level; } public String getName() { return name; } private boolean isRootLogger() { // only the root logger has a null parent return parent == null; } Logger getChildByName(final String childName) { if (childrenList == null) { return null; } else { int len = this.childrenList.size(); for (int i = 0; i < len; i++) { final Logger childLogger_i = (Logger) childrenList.get(i); final String childName_i = childLogger_i.getName(); if (childName.equals(childName_i)) { return childLogger_i; } } // no child found return null; } } public synchronized void setLevel(Level newLevel) { if (level == newLevel) { // nothing to do; return; } if (newLevel == null && isRootLogger()) { throw new IllegalArgumentException("The level of the root logger cannot be set to null"); } level = newLevel; if (newLevel == null) { effectiveLevelInt = parent.effectiveLevelInt; newLevel = parent.getEffectiveLevel(); } else { effectiveLevelInt = newLevel.levelInt; } if (childrenList != null) { int len = childrenList.size(); for (int i = 0; i < len; i++) { Logger child = (Logger) childrenList.get(i); // tell child to handle parent levelInt change child.handleParentLevelChange(effectiveLevelInt); } } // inform listeners loggerContext.fireOnLevelChange(this, newLevel); } /** * This method is invoked by parent logger to let this logger know that the * prent's levelInt changed. * * @param newParentLevelInt */ private synchronized void handleParentLevelChange(int newParentLevelInt) { // changes in the parent levelInt affect children only if their levelInt is // null if (level == null) { effectiveLevelInt = newParentLevelInt; // propagate the parent levelInt change to this logger's children if (childrenList != null) { int len = childrenList.size(); for (int i = 0; i < len; i++) { Logger child = (Logger) childrenList.get(i); child.handleParentLevelChange(newParentLevelInt); } } } } /** * Remove all previously added appenders from this logger instance. * <p/> * This is useful when re-reading configuration information. */ public void detachAndStopAllAppenders() { if (aai != null) { aai.detachAndStopAllAppenders(); } } public boolean detachAppender(String name) { if (aai == null) { return false; } return aai.detachAppender(name); } // this method MUST be synchronized. See comments on 'aai' field for further // details. public synchronized void addAppender(Appender<ILoggingEvent> newAppender) { if (aai == null) { aai = new AppenderAttachableImpl<ILoggingEvent>(); } aai.addAppender(newAppender); } public boolean isAttached(Appender<ILoggingEvent> appender) { if (aai == null) { return false; } return aai.isAttached(appender); } @SuppressWarnings("unchecked") public Iterator<Appender<ILoggingEvent>> iteratorForAppenders() { if (aai == null) { return Collections.EMPTY_LIST.iterator(); } return aai.iteratorForAppenders(); } public Appender<ILoggingEvent> getAppender(String name) { if (aai == null) { return null; } return aai.getAppender(name); } /** * Invoke all the appenders of this logger. * * @param event * The event to log */ public void callAppenders(ILoggingEvent event) { int writes = 0; for (Logger l = this; l != null; l = l.parent) { writes += l.appendLoopOnAppenders(event); if (!l.additive) { break; } } // No appenders in hierarchy if (writes == 0) { loggerContext.noAppenderDefinedWarning(this); } } private int appendLoopOnAppenders(ILoggingEvent event) { if (aai != null) { return aai.appendLoopOnAppenders(event); } else { return 0; } } /** * Remove the appender passed as parameter form the list of appenders. */ public boolean detachAppender(Appender<ILoggingEvent> appender) { if (aai == null) { return false; } return aai.detachAppender(appender); } /** * Create a child of this logger by suffix, that is, the part of the name * extending this logger. For example, if this logger is named "x.y" and the * lastPart is "z", then the created child logger will be named "x.y.z". * * <p> * IMPORTANT: Calls to this method must be within a synchronized block on this * logger. * * @param lastPart * the suffix (i.e. last part) of the child logger name. This * parameter may not include dots, i.e. the logger separator * character. * @return */ Logger createChildByLastNamePart(final String lastPart) { int i_index = LoggerNameUtil.getFirstSeparatorIndexOf(lastPart); if (i_index != -1) { throw new IllegalArgumentException("Child name [" + lastPart + " passed as parameter, may not include [" + CoreConstants.DOT + "]"); } if (childrenList == null) { childrenList = new CopyOnWriteArrayList<Logger>(); } Logger childLogger; if (this.isRootLogger()) { childLogger = new Logger(lastPart, this, this.loggerContext); } else { childLogger = new Logger(name + CoreConstants.DOT + lastPart, this, this.loggerContext); } childrenList.add(childLogger); childLogger.effectiveLevelInt = this.effectiveLevelInt; return childLogger; } private void localLevelReset() { effectiveLevelInt = Level.DEBUG_INT; if (isRootLogger()) { level = Level.DEBUG; } else { level = null; } } void recursiveReset() { detachAndStopAllAppenders(); localLevelReset(); additive = true; if (childrenList == null) { return; } for (Logger childLogger : childrenList) { childLogger.recursiveReset(); } } /** * The default size of child list arrays. The JDK 1.5 default is 10. We use a * smaller value to save a little space. */ Logger createChildByName(final String childName) { int i_index = LoggerNameUtil.getSeparatorIndexOf(childName, this.name.length() + 1); if (i_index != -1) { throw new IllegalArgumentException("For logger [" + this.name + "] child name [" + childName + " passed as parameter, may not include '.' after index" + (this.name.length() + 1)); } if (childrenList == null) { childrenList = new CopyOnWriteArrayList<Logger>(); } Logger childLogger; childLogger = new Logger(childName, this, this.loggerContext); childrenList.add(childLogger); childLogger.effectiveLevelInt = this.effectiveLevelInt; return childLogger; } /** * The next methods are not merged into one because of the time we gain by not * creating a new Object[] with the params. This reduces the cost of not * logging by about 20 nanoseconds. */ private void filterAndLog_0_Or3Plus(final String localFQCN, final Marker marker, final Level level, final String msg, final Object[] params, final Throwable t) { final FilterReply decision = loggerContext.getTurboFilterChainDecision_0_3OrMore(marker, this, level, msg, params, t); if (decision == FilterReply.NEUTRAL) { if (effectiveLevelInt > level.levelInt) { return; } } else if (decision == FilterReply.DENY) { return; } buildLoggingEventAndAppend(localFQCN, marker, level, msg, params, t); } private void filterAndLog_1(final String localFQCN, final Marker marker, final Level level, final String msg, final Object param, final Throwable t) { final FilterReply decision = loggerContext.getTurboFilterChainDecision_1(marker, this, level, msg, param, t); if (decision == FilterReply.NEUTRAL) { if (effectiveLevelInt > level.levelInt) { return; } } else if (decision == FilterReply.DENY) { return; } buildLoggingEventAndAppend(localFQCN, marker, level, msg, new Object[] { param }, t); } private void filterAndLog_2(final String localFQCN, final Marker marker, final Level level, final String msg, final Object param1, final Object param2, final Throwable t) { final FilterReply decision = loggerContext.getTurboFilterChainDecision_2(marker, this, level, msg, param1, param2, t); if (decision == FilterReply.NEUTRAL) { if (effectiveLevelInt > level.levelInt) { return; } } else if (decision == FilterReply.DENY) { return; } buildLoggingEventAndAppend(localFQCN, marker, level, msg, new Object[] { param1, param2 }, t); } private void buildLoggingEventAndAppend(final String localFQCN, final Marker marker, final Level level, final String msg, final Object[] params, final Throwable t) { LoggingEvent le = new LoggingEvent(localFQCN, this, level, msg, t, params); le.setMarker(marker); callAppenders(le); } public void trace(String msg) { filterAndLog_0_Or3Plus(FQCN, null, Level.TRACE, msg, null, null); } public void trace(String format, Object arg) { filterAndLog_1(FQCN, null, Level.TRACE, format, arg, null); } public void trace(String format, Object arg1, Object arg2) { filterAndLog_2(FQCN, null, Level.TRACE, format, arg1, arg2, null); } public void trace(String format, Object... argArray) { filterAndLog_0_Or3Plus(FQCN, null, Level.TRACE, format, argArray, null); } public void trace(String msg, Throwable t) { filterAndLog_0_Or3Plus(FQCN, null, Level.TRACE, msg, null, t); } public void trace(Marker marker, String msg) { filterAndLog_0_Or3Plus(FQCN, marker, Level.TRACE, msg, null, null); } public void trace(Marker marker, String format, Object arg) { filterAndLog_1(FQCN, marker, Level.TRACE, format, arg, null); } public void trace(Marker marker, String format, Object arg1, Object arg2) { filterAndLog_2(FQCN, marker, Level.TRACE, format, arg1, arg2, null); } public void trace(Marker marker, String format, Object... argArray) { filterAndLog_0_Or3Plus(FQCN, marker, Level.TRACE, format, argArray, null); } public void trace(Marker marker, String msg, Throwable t) { filterAndLog_0_Or3Plus(FQCN, marker, Level.TRACE, msg, null, t); } public boolean isDebugEnabled() { return isDebugEnabled(null); } public boolean isDebugEnabled(Marker marker) { final FilterReply decision = callTurboFilters(marker, Level.DEBUG); if (decision == FilterReply.NEUTRAL) { return effectiveLevelInt <= Level.DEBUG_INT; } else if (decision == FilterReply.DENY) { return false; } else if (decision == FilterReply.ACCEPT) { return true; } else { throw new IllegalStateException("Unknown FilterReply value: " + decision); } } public void debug(String msg) { filterAndLog_0_Or3Plus(FQCN, null, Level.DEBUG, msg, null, null); } public void debug(String format, Object arg) { filterAndLog_1(FQCN, null, Level.DEBUG, format, arg, null); } public void debug(String format, Object arg1, Object arg2) { filterAndLog_2(FQCN, null, Level.DEBUG, format, arg1, arg2, null); } public void debug(String format, Object... argArray) { filterAndLog_0_Or3Plus(FQCN, null, Level.DEBUG, format, argArray, null); } public void debug(String msg, Throwable t) { filterAndLog_0_Or3Plus(FQCN, null, Level.DEBUG, msg, null, t); } public void debug(Marker marker, String msg) { filterAndLog_0_Or3Plus(FQCN, marker, Level.DEBUG, msg, null, null); } public void debug(Marker marker, String format, Object arg) { filterAndLog_1(FQCN, marker, Level.DEBUG, format, arg, null); } public void debug(Marker marker, String format, Object arg1, Object arg2) { filterAndLog_2(FQCN, marker, Level.DEBUG, format, arg1, arg2, null); } public void debug(Marker marker, String format, Object... argArray) { filterAndLog_0_Or3Plus(FQCN, marker, Level.DEBUG, format, argArray, null); } public void debug(Marker marker, String msg, Throwable t) { filterAndLog_0_Or3Plus(FQCN, marker, Level.DEBUG, msg, null, t); } public void error(String msg) { filterAndLog_0_Or3Plus(FQCN, null, Level.ERROR, msg, null, null); } public void error(String format, Object arg) { filterAndLog_1(FQCN, null, Level.ERROR, format, arg, null); } public void error(String format, Object arg1, Object arg2) { filterAndLog_2(FQCN, null, Level.ERROR, format, arg1, arg2, null); } public void error(String format, Object... argArray) { filterAndLog_0_Or3Plus(FQCN, null, Level.ERROR, format, argArray, null); } public void error(String msg, Throwable t) { filterAndLog_0_Or3Plus(FQCN, null, Level.ERROR, msg, null, t); } public void error(Marker marker, String msg) { filterAndLog_0_Or3Plus(FQCN, marker, Level.ERROR, msg, null, null); } public void error(Marker marker, String format, Object arg) { filterAndLog_1(FQCN, marker, Level.ERROR, format, arg, null); } public void error(Marker marker, String format, Object arg1, Object arg2) { filterAndLog_2(FQCN, marker, Level.ERROR, format, arg1, arg2, null); } public void error(Marker marker, String format, Object... argArray) { filterAndLog_0_Or3Plus(FQCN, marker, Level.ERROR, format, argArray, null); } public void error(Marker marker, String msg, Throwable t) { filterAndLog_0_Or3Plus(FQCN, marker, Level.ERROR, msg, null, t); } public boolean isInfoEnabled() { return isInfoEnabled(null); } public boolean isInfoEnabled(Marker marker) { FilterReply decision = callTurboFilters(marker, Level.INFO); if (decision == FilterReply.NEUTRAL) { return effectiveLevelInt <= Level.INFO_INT; } else if (decision == FilterReply.DENY) { return false; } else if (decision == FilterReply.ACCEPT) { return true; } else { throw new IllegalStateException("Unknown FilterReply value: " + decision); } } public void info(String msg) { filterAndLog_0_Or3Plus(FQCN, null, Level.INFO, msg, null, null); } public void info(String format, Object arg) { filterAndLog_1(FQCN, null, Level.INFO, format, arg, null); } public void info(String format, Object arg1, Object arg2) { filterAndLog_2(FQCN, null, Level.INFO, format, arg1, arg2, null); } public void info(String format, Object... argArray) { filterAndLog_0_Or3Plus(FQCN, null, Level.INFO, format, argArray, null); } public void info(String msg, Throwable t) { filterAndLog_0_Or3Plus(FQCN, null, Level.INFO, msg, null, t); } public void info(Marker marker, String msg) { filterAndLog_0_Or3Plus(FQCN, marker, Level.INFO, msg, null, null); } public void info(Marker marker, String format, Object arg) { filterAndLog_1(FQCN, marker, Level.INFO, format, arg, null); } public void info(Marker marker, String format, Object arg1, Object arg2) { filterAndLog_2(FQCN, marker, Level.INFO, format, arg1, arg2, null); } public void info(Marker marker, String format, Object... argArray) { filterAndLog_0_Or3Plus(FQCN, marker, Level.INFO, format, argArray, null); } public void info(Marker marker, String msg, Throwable t) { filterAndLog_0_Or3Plus(FQCN, marker, Level.INFO, msg, null, t); } public boolean isTraceEnabled() { return isTraceEnabled(null); } public boolean isTraceEnabled(Marker marker) { final FilterReply decision = callTurboFilters(marker, Level.TRACE); if (decision == FilterReply.NEUTRAL) { return effectiveLevelInt <= Level.TRACE_INT; } else if (decision == FilterReply.DENY) { return false; } else if (decision == FilterReply.ACCEPT) { return true; } else { throw new IllegalStateException("Unknown FilterReply value: " + decision); } } public boolean isErrorEnabled() { return isErrorEnabled(null); } public boolean isErrorEnabled(Marker marker) { FilterReply decision = callTurboFilters(marker, Level.ERROR); if (decision == FilterReply.NEUTRAL) { return effectiveLevelInt <= Level.ERROR_INT; } else if (decision == FilterReply.DENY) { return false; } else if (decision == FilterReply.ACCEPT) { return true; } else { throw new IllegalStateException("Unknown FilterReply value: " + decision); } } public boolean isWarnEnabled() { return isWarnEnabled(null); } public boolean isWarnEnabled(Marker marker) { FilterReply decision = callTurboFilters(marker, Level.WARN); if (decision == FilterReply.NEUTRAL) { return effectiveLevelInt <= Level.WARN_INT; } else if (decision == FilterReply.DENY) { return false; } else if (decision == FilterReply.ACCEPT) { return true; } else { throw new IllegalStateException("Unknown FilterReply value: " + decision); } } public boolean isEnabledFor(Marker marker, Level level) { FilterReply decision = callTurboFilters(marker, level); if (decision == FilterReply.NEUTRAL) { return effectiveLevelInt <= level.levelInt; } else if (decision == FilterReply.DENY) { return false; } else if (decision == FilterReply.ACCEPT) { return true; } else { throw new IllegalStateException("Unknown FilterReply value: " + decision); } } public boolean isEnabledFor(Level level) { return isEnabledFor(null, level); } public void warn(String msg) { filterAndLog_0_Or3Plus(FQCN, null, Level.WARN, msg, null, null); } public void warn(String msg, Throwable t) { filterAndLog_0_Or3Plus(FQCN, null, Level.WARN, msg, null, t); } public void warn(String format, Object arg) { filterAndLog_1(FQCN, null, Level.WARN, format, arg, null); } public void warn(String format, Object arg1, Object arg2) { filterAndLog_2(FQCN, null, Level.WARN, format, arg1, arg2, null); } public void warn(String format, Object... argArray) { filterAndLog_0_Or3Plus(FQCN, null, Level.WARN, format, argArray, null); } public void warn(Marker marker, String msg) { filterAndLog_0_Or3Plus(FQCN, marker, Level.WARN, msg, null, null); } public void warn(Marker marker, String format, Object arg) { filterAndLog_1(FQCN, marker, Level.WARN, format, arg, null); } public void warn(Marker marker, String format, Object... argArray) { filterAndLog_0_Or3Plus(FQCN, marker, Level.WARN, format, argArray, null); } public void warn(Marker marker, String format, Object arg1, Object arg2) { filterAndLog_2(FQCN, marker, Level.WARN, format, arg1, arg2, null); } public void warn(Marker marker, String msg, Throwable t) { filterAndLog_0_Or3Plus(FQCN, marker, Level.WARN, msg, null, t); } public boolean isAdditive() { return additive; } public void setAdditive(boolean additive) { this.additive = additive; } public String toString() { return "Logger[" + name + "]"; } /** * Method that calls the attached TurboFilter objects based on the logger and * the level. * * It is used by isYYYEnabled() methods. * * It returns the typical FilterReply values: ACCEPT, NEUTRAL or DENY. * * @param level * @return the reply given by the TurboFilters */ private FilterReply callTurboFilters(Marker marker, Level level) { return loggerContext.getTurboFilterChainDecision_0_3OrMore(marker, this, level, null, null, null); } /** * Return the context for this logger. * * @return the context */ public LoggerContext getLoggerContext() { return loggerContext; } public void log(Marker marker, String fqcn, int levelInt, String message, Object[] argArray, Throwable t) { Level level = Level.fromLocationAwareLoggerInteger(levelInt); filterAndLog_0_Or3Plus(fqcn, marker, level, message, argArray, t); } /** * Support SLF4J interception during initialization as introduced in SLF4J version 1.7.15 * @since 1.1.4 * @param slf4jEvent */ public void log(org.slf4j.event.LoggingEvent slf4jEvent) { Level level = Level.fromLocationAwareLoggerInteger(slf4jEvent.getLevel().toInt()); filterAndLog_0_Or3Plus(FQCN, slf4jEvent.getMarker(), level, slf4jEvent.getMessage(), slf4jEvent.getArgumentArray(), slf4jEvent.getThrowable()); } /** * After serialization, the logger instance does not know its LoggerContext. * The best we can do here, is to return a logger with the same name * returned by org.slf4j.LoggerFactory. * * @return Logger instance with the same name * @throws ObjectStreamException */ protected Object readResolve() throws ObjectStreamException { return LoggerFactory.getLogger(getName()); } }
博客来源：
由于使用的版本较高，本文稍有不同，新版本中也见到很多新的编程思想