Class Logging

java.lang.Object
org.apache.sis.util.Static
org.apache.sis.util.logging.Logging

public final class Logging extends Static
A set of utilities method for configuring loggings in SIS. This class provides also some convenience static methods, including:
Since:
0.3
Version:
1.3
  • Field Details

  • Constructor Details

    • Logging

      private Logging()
      Do not allow instantiation of this class.
  • Method Details

    • getLogger

      public static Logger getLogger(Class<?> source)
      Returns a logger for the package of the specified class. This convenience method invokes Logger.getLogger(String) with the package name of the given class taken as the logger name.
      Parameters:
      source - the class which will emit a logging message.
      Returns:
      a logger for the specified class.
      Since:
      1.0
    • log

      public static void log(Class<?> classe, String method, LogRecord record)
      Logs the given record to the logger associated to the given class. This convenience method performs the following steps:
      Parameters:
      classe - the class to report as the source of the logging message.
      method - the method to report as the source of the logging message.
      record - the record to log.
    • inferCaller

      private static Logger inferCaller(Logger logger, String classe, String method, StackTraceElement[] trace, LogRecord record)
      Sets the LogRecord source class and method names according values inferred from the given stack trace. This method inspects the given stack trace, skips what looks like internal API based on heuristic rules, then if some arguments are non-null tries to match them.
      Parameters:
      logger - where the log record will be sent after this method call, or null if unknown.
      classe - the name of the class to report in the log record, or null if unknown.
      method - the name of the method to report in the log record, or null if unknown.
      trace - the stack trace to use for inferring the class and method names.
      record - the record where to set the class and method names.
      Returns:
      the record to use for logging the record.
    • isPublic

      private static boolean isPublic(StackTraceElement e)
      Returns true if the given stack trace element describes a method considered part of public API. This method is invoked in order to infer the class and method names to declare in a LogRecord. We do not document this feature in public Javadoc because it is based on heuristic rules that may change.

      The current implementation compares the class name against a hard-coded list of classes to hide. This implementation may change in any future SIS version.

      Parameters:
      e - a stack trace element.
      Returns:
      true if the class and method specified by the given element can be considered public API.
    • unexpectedException

      public static boolean unexpectedException(Logger logger, Class<?> classe, String method, Throwable error)
      Invoked when an unexpected error occurred. This method logs a message at Level.WARNING to the specified logger. The originating class name and method name can optionally be specified. If any of them is null, then it will be inferred from the error stack trace as described below.
      Recommended usage: explicit value for class and method names are preferred to automatic inference for the following reasons:
      • Automatic inference is not 100% reliable, since the Java Virtual Machine is free to omit stack frame in optimized code.
      • When an exception occurred in a private method used internally by a public method, we sometimes want to log the warning for the public method instead, since the user is not expected to know anything about the existence of the private method. If a developer really want to know about the private method, the stack trace is still available anyway.
      If the classe or method arguments are null, then the originating class name and method name are inferred from the given error using the first stack trace element for which the class name is inside a package or sub-package of the same name than the logger name.
      Example: if the logger name is "org.apache.sis.image", then this method will uses the first stack trace element where the fully qualified class name starts with "org.apache.sis.image" or "org.apache.sis.image.io", but not "org.apache.sis.imageio".
      Parameters:
      logger - where to log the error, or null for inferring a default value from other arguments.
      classe - the class where the error occurred, or null for inferring a default value from other arguments.
      method - the method where the error occurred, or null for inferring a default value from other arguments.
      error - the error, or null if none.
      Returns:
      true if the error has been logged, or false if the given error was null or if the logger does not log anything at Level.WARNING.
      See Also:
    • unexpectedException

      private static boolean unexpectedException(Logger logger, String classe, String method, Throwable error, Level level)
      Parameters:
      logger - where to log the error, or null for inferring a default value from other arguments.
      classe - the fully qualified class name where the error occurred, or null for inferring a default value from other arguments.
      method - the method where the error occurred, or null for inferring a default value from other arguments.
      error - the error, or null if none.
      level - the logging level.
      Returns:
      true if the error has been logged, or false if the given error was null or if the logger does not log anything at the specified level.
    • configurationException

      static boolean configurationException(Logger logger, Class<?> classe, String method, Throwable error)
      Invoked when an unexpected error occurred while configuring the system. The error shall not prevent the application from working, but may change the behavior in some minor aspects.
      Example: If the org.apache.sis.util.logging.MonolineFormatter.time pattern declared in the jre/lib/logging.properties file is illegal, then MonolineFormatter will log this problem and use a default time pattern.
      Parameters:
      logger - where to log the error, or null for inferring a default value from other arguments.
      classe - the class where the error occurred, or null for inferring a default value from other arguments.
      method - the method name where the error occurred, or null for inferring a default value from other arguments.
      error - the error, or null if none.
      Returns:
      true if the error has been logged, or false if the given error was null or if the logger does not log anything at Level.CONFIG.
      See Also:
    • recoverableException

      public static boolean recoverableException(Logger logger, Class<?> classe, String method, Throwable error)
      Invoked when a recoverable error occurred. This method is similar to unexpectedException(…) except that it does not log the stack trace and uses a lower logging level.
      Parameters:
      logger - where to log the error, or null for inferring a default value from other arguments.
      classe - the class where the error occurred, or null for inferring a default value from other arguments.
      method - the method name where the error occurred, or null for inferring a default value from other arguments.
      error - the error, or null if none.
      Returns:
      true if the error has been logged, or false if the given error was null or if the logger does not log anything at Level.FINE.
      See Also:
    • ignorableException

      public static boolean ignorableException(Logger logger, Class<?> classe, String method, Throwable error)
      Invoked when an ignorable error occurred. This method is similar to unexpectedException(…) except that it uses a lower logging level.
      Parameters:
      logger - where to log the error, or null for inferring a default value from other arguments.
      classe - the class where the error occurred, or null for inferring a default value from other arguments.
      method - the method name where the error occurred, or null for inferring a default value from other arguments.
      error - the error, or null if none.
      Returns:
      true if the error has been logged, or false if the given error was null or if the logger does not log anything at Level.FINER.
      Since:
      1.0
    • severeException

      public static boolean severeException(Logger logger, Class<?> classe, String method, Throwable error)
      Invoked when a severe error occurred. This method is similar to unexpectedException except that it logs the message at the SEVERE level.
      Parameters:
      logger - where to log the error, or null for inferring a default value from other arguments.
      classe - the class where the error occurred, or null for inferring a default value from other arguments.
      method - the method name where the error occurred, or null for inferring a default value from other arguments.
      error - the error, or null if none.
      Returns:
      true if the error has been logged, or false if the given error was null or if the logger does not log anything at Level.SEVERE.
      See Also: