testing caller info extraction with slf4j-jpl

Signed-off-by: Ceki Gulcu <ceki@qos.ch>

slf4j-api/src/main/java/org/slf4j/event/DefaultLoggingEvent.java

@@ -27,6 +27,8 @@ public class DefaultLoggingEvent implements LoggingEvent {
     Throwable throwable;
     String threadName;
     long timeStamp;
+    
+    String callerBoundary;
 
     public DefaultLoggingEvent(Level level, Logger logger) {
         this.logger = logger;
@@ -123,4 +125,12 @@ public class DefaultLoggingEvent implements LoggingEvent {
     public long getTimeStamp() {
         return timeStamp;
     }
+
+    public void setCallerBoundary(String fqcn) {
+        this.callerBoundary = fqcn;
+    }
+    
+    public String getCallerBoundary() {
+        return callerBoundary;
+    }
 }

slf4j-api/src/main/java/org/slf4j/event/LoggingEvent.java

@@ -32,4 +32,14 @@ public interface LoggingEvent {
     long getTimeStamp();
 
     String getThreadName();
+ 
+    /**
+     * Returns the presumed caller boundary provided by the logging library (not the user of the library). 
+     * Null by default.
+     *  
+     * @return presumed caller, null by default.
+     */
+    default String getCallerBoundary() {
+        return null;
+    }
 }

slf4j-api/src/main/java/org/slf4j/spi/CallerBoundaryAware.java

@@ -0,0 +1,23 @@
+package org.slf4j.spi;
+
+
+/**
+ * Additional interface to {@link LoggingEventBuilder} and {@link LoggingEvent}. 
+ * 
+ * Implementations of {@link LoggingEventBuilder} and  {@link LoggingEvent} may optionally 
+ * implement {@link CallerBoundaryAware} in order to support caller info extraction.
+ *
+ * This interface is intended for use by logging backends or logging bridges. 
+ * 
+ * @author Ceki Gulcu
+ *
+ */
+public interface CallerBoundaryAware {
+
+    /**
+     * Add a fqcn (fully qualified class name) to this event, presumed to be the caller boundary.
+     * 
+     * @param fqcn
+     */
+    void setCallerBoundary(String fqcn);
+}

slf4j-api/src/main/java/org/slf4j/spi/DefaultLoggingEventBuilder.java

@@ -9,7 +9,7 @@ import org.slf4j.event.KeyValuePair;
 import org.slf4j.event.Level;
 import org.slf4j.event.LoggingEvent;
 
-public class DefaultLoggingEventBuilder implements LoggingEventBuilder {
+public class DefaultLoggingEventBuilder implements LoggingEventBuilder, CallerBoundaryAware {
 
     protected DefaultLoggingEvent loggingEvent;
     protected Logger logger;
@@ -50,6 +50,11 @@ public class DefaultLoggingEventBuilder implements LoggingEventBuilder {
         return this;
     }
 
+    @Override
+    public void setCallerBoundary(String fqcn) {
+        loggingEvent.setCallerBoundary(fqcn);
+    }
+    
     @Override
     public void log(String message) {
         loggingEvent.setMessage(message);
@@ -187,4 +192,8 @@ public class DefaultLoggingEventBuilder implements LoggingEventBuilder {
         return this;
     }
 
+    
+
+    
+
 }

slf4j-api/src/main/java/org/slf4j/spi/LoggingEventBuilder.java

@@ -29,7 +29,7 @@ import java.util.function.Supplier;
 import org.slf4j.Marker;
 
 /**
- * A fluent API for creating logging events.
+ * This is main interface in slf4j's fluent API for creating logging events.
  * 
  * @author Ceki Gülcü
  * @since 2.0.0

slf4j-jdk-platform-logging/src/main/java/org/slf4j/jdk/platform/logging/SLF4JPlarformLogger.java

@@ -30,6 +30,7 @@ import java.util.MissingResourceException;
 import java.util.ResourceBundle;
 
 import org.slf4j.Logger;
+import org.slf4j.spi.CallerBoundaryAware;
 import org.slf4j.spi.LoggingEventBuilder;
 
 /**
@@ -38,6 +39,8 @@ import org.slf4j.spi.LoggingEventBuilder;
  */
 class SLF4JPlarformLogger implements System.Logger {
 
+    static private String PRESUMED_CALLER_BOUNDARY = System.Logger.class.getName();
+                    
     private final Logger slf4jLogger;
 
     public SLF4JPlarformLogger(Logger logger) {
@@ -141,6 +144,10 @@ class SLF4JPlarformLogger implements System.Logger {
             // The JDK uses a different formatting convention. We must invoke it now.
             message = String.format(message, params);
         }
+        if(leb instanceof CallerBoundaryAware) {
+            CallerBoundaryAware cba = (CallerBoundaryAware) leb;
+            cba.setCallerBoundary(PRESUMED_CALLER_BOUNDARY);
+        }
         leb.log(message);
     }