reactor.util

Class Loggers

java.lang.Object

reactor.util.Loggers

public abstract class Loggers
extends Object

Expose static methods to get a logger depending on the environment. If SL4J is on the classpath, it will be used. Otherwise, there are two possible fallbacks: Console or java.util.logging.Logger). By default, the Console fallback is used. To use the JDK loggers, set the "reactor.logging.fallback" System property to "JDK".

One can also force the implementation by using the "useXXX" static methods: useConsoleLoggers(), useVerboseConsoleLoggers(), useJdkLoggers() and useSl4jLoggers() (which may throw an Exception if the library isn't on the classpath). Note that the system property method above is preferred, as no cleanup of the logger factory initialized at startup is attempted by the useXXX methods.

Field Summary

Fields

Modifier and Type	Field and Description
static String	FALLBACK_PROPERTY The system property that determines which fallback implementation to use for loggers when SLF4J isn't available.

Method Summary

Modifier and Type	Method and Description
static Logger	getLogger(Class<?> cls) Get a Logger, backed by SLF4J if present on the classpath or falling back to java.util.logging.Logger.
static Logger	getLogger(String name) Get a Logger.
static void	resetLoggerFactory() Attempt to activate the best reactor Logger factory, by first attempting to use the SLF4J one, then falling back to either Console logging or java.util.logging.Logger).
static void	useConsoleLoggers() Force the usage of Console-based Loggers, even if SLF4J is available on the classpath.
static void	useCustomLoggers(Function<String,? extends Logger> loggerFactory) Use a custom type of Logger created through the provided Function, which takes a logger name as input.
static void	useJdkLoggers() Force the usage of JDK-based Loggers, even if SLF4J is available on the classpath.
static void	useSl4jLoggers() Force the usage of SL4J-based Loggers, throwing an exception if SLF4J isn't available on the classpath.
static void	useVerboseConsoleLoggers() Force the usage of Console-based Loggers, even if SLF4J is available on the classpath.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

FALLBACK_PROPERTY

public static final String FALLBACK_PROPERTY

The system property that determines which fallback implementation to use for loggers when SLF4J isn't available. Use JDK for the JDK-backed logging and anything else for Console-based (the default).

See Also:

Constant Field Values

Method Detail

resetLoggerFactory

public static void resetLoggerFactory()

Attempt to activate the best reactor Logger factory, by first attempting to use the SLF4J one, then falling back to either Console logging or java.util.logging.Logger). By default, the Console fallback is used. To fallback to the JDK loggers, set the "reactor.logging.fallback" System property to "JDK".

See Also:

useJdkLoggers(), useConsoleLoggers(), useVerboseConsoleLoggers()

useConsoleLoggers

public static void useConsoleLoggers()

Force the usage of Console-based Loggers, even if SLF4J is available on the classpath. Console loggers will output ERROR and WARN levels to System.err and levels below to System.out. All levels except TRACE and DEBUG are considered enabled. TRACE and DEBUG are omitted.

The previously active logger factory is simply replaced without any particular clean-up.

useVerboseConsoleLoggers

public static void useVerboseConsoleLoggers()

Force the usage of Console-based Loggers, even if SLF4J is available on the classpath. Console loggers will output ERROR and WARN levels to System.err and levels below to System.out. All levels (including TRACE and DEBUG) are considered enabled.

The previously active logger factory is simply replaced without any particular clean-up.

useCustomLoggers

public static void useCustomLoggers(Function<String,? extends Logger> loggerFactory)

Use a custom type of Logger created through the provided Function, which takes a logger name as input.

The previously active logger factory is simply replaced without any particular clean-up.

Thread-safety

Given logger acquisition function must be thread-safe. It means that it is user responsibility to ensure that any internal state and cache used by the provided function is properly synchronized.

Parameters:

loggerFactory - the Function that provides a (possibly cached) Logger given a name.

useJdkLoggers

public static void useJdkLoggers()

Force the usage of JDK-based Loggers, even if SLF4J is available on the classpath.

The previously active logger factory is simply replaced without any particular clean-up.

useSl4jLoggers

public static void useSl4jLoggers()

Force the usage of SL4J-based Loggers, throwing an exception if SLF4J isn't available on the classpath. Prefer using resetLoggerFactory() as it will fallback in the later case.

The previously active logger factory is simply replaced without any particular clean-up.

getLogger

public static Logger getLogger(String name)

Get a Logger.

For a notion of how the backing implementation is chosen, see resetLoggerFactory() (or call one of the useXxxLoggers methods).

Parameters:

name - the category or logger name to use

Returns:

a new Logger instance

getLogger

public static Logger getLogger(Class<?> cls)

Get a Logger, backed by SLF4J if present on the classpath or falling back to java.util.logging.Logger.

Parameters:

cls - the source Class to derive the logger name from.

Returns:

a new Logger instance