Compatibility old log4j

[duylong]

Hi,

Many applications still use a log4j version < 1.2.15. Is it possible to keep compatibility with these versions? because we can not update.

The differences are mainly attributes which change public to private and cause some errors "method not found".

Best regards,

[lusis]

@duylong Let me do some investigation. I might be able to pull something off as long as it means it still works going forward.

[duylong]

I tried copying the missing methods and I have a working version but I think it is not very clean.

Here are my changes :

+ import java.util.Collections;
+ import java.util.Hashtable;
+ import org.apache.log4j.MDC;
...
+    private Hashtable mdcCopy;
+    private boolean mdcCopyLookupRequired = true;
...
+   /**
+    * Obtain a copy of this thread's MDC prior to serialization or
+    * asynchronous logging.
+    */
+    public
+    void getMDCCopy() {
+       if(this.mdcCopyLookupRequired) {
+            this.mdcCopyLookupRequired = false;
+            // the clone call is required for asynchronous logging.
+            // See also bug #5932.
+            Hashtable t = (Hashtable) MDC.getContext();
+            if(t != null) {
+                this.mdcCopy = (Hashtable) t.clone();
+            }
+        }
+    }

+    /**
+     * Returns the set of properties for the event. The returned set is unmodifiable by the caller.
+     */
+    public Map getProperties() {
+        this.getMDCCopy();
+        Map properties;
+        if (this.mdcCopy == null) {
+            properties = new HashMap();
+        } else {
+            properties = this.mdcCopy;
+        }
+        return Collections.unmodifiableMap(properties);
+    }
...
-        timestamp = loggingEvent.getTimeStamp();
+        timestamp = loggingEvent.timeStamp;
...         
-        mdc = loggingEvent.getProperties();
+        mdc = this.getProperties();