Package io.github.cjstehno.testthings.slf4j

Class InMemoryLogAppender

java.lang.Object
ch.qos.logback.core.spi.ContextAwareBase
ch.qos.logback.core.AppenderBase<ch.qos.logback.classic.spi.ILoggingEvent>
io.github.cjstehno.testthings.slf4j.InMemoryLogAppender
All Implemented Interfaces:
ch.qos.logback.core.Appender<ch.qos.logback.classic.spi.ILoggingEvent>, ch.qos.logback.core.spi.ContextAware, ch.qos.logback.core.spi.FilterAttachable<ch.qos.logback.classic.spi.ILoggingEvent>, ch.qos.logback.core.spi.LifeCycle
public class InMemoryLogAppender extends ch.qos.logback.core.AppenderBase<ch.qos.logback.classic.spi.ILoggingEvent>
An Appender for the SLF4J logging library (with logback backend) that allows for verifying results that may only appear in log messages.

To use this appender you register the classes to be monitored using the loggedClass(Class) configuration method and then call the attach() method on the appender to hook it into the logging system.

You should ensure that the detach() method is also called when you are done testing so that the test code is not left in the logger configuration.

Various methods are provided to read through and filter the captured log messages.

See also the LogAppenderExtension for a simple means of using this in tests.

  • Field Summary

    Fields inherited from class ch.qos.logback.core.AppenderBase

    name, started

    Fields inherited from class ch.qos.logback.core.spi.ContextAwareBase

    context

  • Constructor Summary

    Constructors
    Constructor
    Description
    InMemoryLogAppender(AppenderConfig config)
    Creates a log appender with the provided configuration object.
    InMemoryLogAppender(Consumer<AppenderConfig> consumer)
    Creates an in-memory Logback Appender for testing with the provided configuration.

  • Method Summary

    Modifier and Type
    Method
    Description
    protected void
    append(ch.qos.logback.classic.spi.ILoggingEvent event)
    Called when a logging event is to be added to the appender.
    void
    attach()
    Must be called to initiate the log event recording - to register the log appender with the logger.
    int
    count()
    Counts all captured logging events.
    int
    count(org.hamcrest.Matcher<ch.qos.logback.classic.spi.ILoggingEvent> matcher)
    Counts the number of captured events matching the provided matcher.
    void
    detach()
    Should be called when done using the appender to clean up resources.
    List<ch.qos.logback.classic.spi.ILoggingEvent>
    events()
    Retrieves all captured logging events.
    List<ch.qos.logback.classic.spi.ILoggingEvent>
    events(org.hamcrest.Matcher<ch.qos.logback.classic.spi.ILoggingEvent> matcher)
    Retrieves all captured logging events matching the provided matcher.
    boolean
    hasEvent(org.hamcrest.Matcher<ch.qos.logback.classic.spi.ILoggingEvent> matcher)
    Returns true if there is at least one captured logging event matching the provided matcher.
    Stream<ch.qos.logback.classic.spi.ILoggingEvent>
    stream()
    Retrieves the captured logging events as a Stream.
    Stream<ch.qos.logback.classic.spi.ILoggingEvent>
    stream(org.hamcrest.Matcher<ch.qos.logback.classic.spi.ILoggingEvent> matcher)
    Retrieves the captured logging events matching the provided matcher, as a Stream.

    Methods inherited from class ch.qos.logback.core.AppenderBase

    addFilter, clearAllFilters, doAppend, getCopyOfAttachedFiltersList, getFilterChainDecision, getName, isStarted, setName, start, stop, toString

    Methods inherited from class ch.qos.logback.core.spi.ContextAwareBase

    addError, addError, addInfo, addInfo, addStatus, addWarn, addWarn, getContext, getDeclaredOrigin, getStatusManager, setContext

    Methods inherited from class java.lang.Object

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

    Methods inherited from interface ch.qos.logback.core.spi.ContextAware

    addError, addError, addInfo, addInfo, addStatus, addWarn, addWarn, getContext, setContext

  • Constructor Details

    • InMemoryLogAppender

      public InMemoryLogAppender(Consumer<AppenderConfig> consumer)
      Creates an in-memory Logback Appender for testing with the provided configuration.
      Parameters:
      consumer - the configuration

    • InMemoryLogAppender

      public InMemoryLogAppender(AppenderConfig config)
      Creates a log appender with the provided configuration object.
      Parameters:
      config - the configuration object

  • Method Details

    • attach

      public void attach()
      Must be called to initiate the log event recording - to register the log appender with the logger.

    • detach

      public void detach()
      Should be called when done using the appender to clean up resources.

    • append

      protected void append(ch.qos.logback.classic.spi.ILoggingEvent event)
      Called when a logging event is to be added to the appender.
      Specified by:
      append in class ch.qos.logback.core.AppenderBase<ch.qos.logback.classic.spi.ILoggingEvent>
      Parameters:
      event - the logging event

    • count

      public int count(org.hamcrest.Matcher<ch.qos.logback.classic.spi.ILoggingEvent> matcher)
      Counts the number of captured events matching the provided matcher.
      Parameters:
      matcher - the event matcher
      Returns:
      the count of matching events

    • count

      public int count()
      Counts all captured logging events.
      Returns:
      the count

    • events

      public List<ch.qos.logback.classic.spi.ILoggingEvent> events(org.hamcrest.Matcher<ch.qos.logback.classic.spi.ILoggingEvent> matcher)
      Retrieves all captured logging events matching the provided matcher.
      Parameters:
      matcher - the matcher
      Returns:
      the list of matching events

    • events

      public List<ch.qos.logback.classic.spi.ILoggingEvent> events()
      Retrieves all captured logging events.
      Returns:
      all captured logging events

    • hasEvent

      public boolean hasEvent(org.hamcrest.Matcher<ch.qos.logback.classic.spi.ILoggingEvent> matcher)
      Returns true if there is at least one captured logging event matching the provided matcher.
      Parameters:
      matcher - the matcher
      Returns:
      true if there is a matching event

    • stream

      public Stream<ch.qos.logback.classic.spi.ILoggingEvent> stream(org.hamcrest.Matcher<ch.qos.logback.classic.spi.ILoggingEvent> matcher)
      Retrieves the captured logging events matching the provided matcher, as a Stream.
      Parameters:
      matcher - the matcher
      Returns:
      the stream of matching events

    • stream

      public Stream<ch.qos.logback.classic.spi.ILoggingEvent> stream()
      Retrieves the captured logging events as a Stream.
      Returns:
      the stream of events