Package org.apache.commons.logging

Interface Log

  • All Known Implementing Classes:
    NoOpLog, SimpleLog, SLF4JLocationAwareLog, SLF4JLog
    public interface Log

    A simple logging interface abstracting logging APIs. In order to be instantiated successfully by LogFactory, classes that implement this interface must have a constructor that takes a single String parameter representing the "name" of this Log.

    The six logging levels used by Log are (in order):

    1. trace (the least serious)
    2. debug
    3. info
    4. warn
    5. error
    6. fatal (the most serious)
    The mapping of these log levels to the concepts used by the underlying logging system is implementation dependent. The implementation should ensure, though, that this ordering behaves as expected.

    Performance is often a logging concern. By examining the appropriate property, a component can avoid expensive operations (producing information to be logged).

    For example, 

        if (log.isDebugEnabled()) {
        ... do something expensive ...
        log.debug(theResult);
    }

    Configuration of the underlying logging system will generally be done external to the Logging APIs, through whatever mechanism is supported by that system.

    Please note that this interface is identical to that found in JCL 1.1.1.

    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      void debug​(java.lang.Object message)
      Log a message with debug log level.
      void debug​(java.lang.Object message, java.lang.Throwable t)
      Log an error with debug log level.
      void error​(java.lang.Object message)
      Log a message with error log level.
      void error​(java.lang.Object message, java.lang.Throwable t)
      Log an error with error log level.
      void fatal​(java.lang.Object message)
      Log a message with fatal log level.
      void fatal​(java.lang.Object message, java.lang.Throwable t)
      Log an error with fatal log level.
      void info​(java.lang.Object message)
      Log a message with info log level.
      void info​(java.lang.Object message, java.lang.Throwable t)
      Log an error with info log level.
      boolean isDebugEnabled()
      Is debug logging currently enabled?
      boolean isErrorEnabled()
      Is error logging currently enabled?
      boolean isFatalEnabled()
      Is fatal logging currently enabled?
      boolean isInfoEnabled()
      Is info logging currently enabled?
      boolean isTraceEnabled()
      Is trace logging currently enabled?
      boolean isWarnEnabled()
      Is warn logging currently enabled?
      void trace​(java.lang.Object message)
      Log a message with trace log level.
      void trace​(java.lang.Object message, java.lang.Throwable t)
      Log an error with trace log level.
      void warn​(java.lang.Object message)
      Log a message with warn log level.
      void warn​(java.lang.Object message, java.lang.Throwable t)
      Log an error with warn log level.

    • Method Detail

      • isDebugEnabled

        boolean isDebugEnabled()

        Is debug logging currently enabled?

        Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than debug.

      • isErrorEnabled

        boolean isErrorEnabled()

        Is error logging currently enabled?

        Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than error.

      • isFatalEnabled

        boolean isFatalEnabled()

        Is fatal logging currently enabled?

        Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than fatal.

      • isInfoEnabled

        boolean isInfoEnabled()

        Is info logging currently enabled?

        Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than info.

        Returns:
        true if info enabled, false otherwise

      • isTraceEnabled

        boolean isTraceEnabled()

        Is trace logging currently enabled?

        Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than trace.

        Returns:
        true if trace enabled, false otherwise

      • isWarnEnabled

        boolean isWarnEnabled()

        Is warn logging currently enabled?

        Call this method to prevent having to perform expensive operations (for example, String concatenation) when the log level is more than warn.

      • trace

        void trace​(java.lang.Object message)

        Log a message with trace log level.

        Parameters:
        message - log this message

      • trace

        void trace​(java.lang.Object message,
           java.lang.Throwable t)

        Log an error with trace log level.

        Parameters:
        message - log this message
        t - log this cause

      • debug

        void debug​(java.lang.Object message)

        Log a message with debug log level.

        Parameters:
        message - log this message

      • debug

        void debug​(java.lang.Object message,
           java.lang.Throwable t)

        Log an error with debug log level.

        Parameters:
        message - log this message
        t - log this cause

      • info

        void info​(java.lang.Object message)

        Log a message with info log level.

        Parameters:
        message - log this message

      • info

        void info​(java.lang.Object message,
          java.lang.Throwable t)

        Log an error with info log level.

        Parameters:
        message - log this message
        t - log this cause

      • warn

        void warn​(java.lang.Object message)

        Log a message with warn log level.

        Parameters:
        message - log this message

      • warn

        void warn​(java.lang.Object message,
          java.lang.Throwable t)

        Log an error with warn log level.

        Parameters:
        message - log this message
        t - log this cause

      • error

        void error​(java.lang.Object message)

        Log a message with error log level.

        Parameters:
        message - log this message

      • error

        void error​(java.lang.Object message,
           java.lang.Throwable t)

        Log an error with error log level.

        Parameters:
        message - log this message
        t - log this cause

      • fatal

        void fatal​(java.lang.Object message)

        Log a message with fatal log level.

        Parameters:
        message - log this message

      • fatal

        void fatal​(java.lang.Object message,
           java.lang.Throwable t)

        Log an error with fatal log level.

        Parameters:
        message - log this message
        t - log this cause