Adds support for logging trace logs to stderr

ServerCore/java/org/elkoserver/util/trace/TraceLog.java

@@ -30,6 +30,9 @@ class TraceLog implements TraceMessageAcceptor {
     /** Flag controlling whether a log file should be written at all. */
     private boolean amWriteEnabled = false;
 
+    /** Flag controlling whether log messages should be sent to stderr. */
+    private boolean logToStderr = false;
+
     /** Log file size above which the file will be rolled over, in chars. */
     private long myMaxSize = STARTING_LOG_SIZE_THRESHOLD;
 
@@ -103,20 +106,24 @@ public synchronized void accept(TraceMessage message) {
     private void outputMessage(TraceMessage message) {
         message.stringify(myStringBuffer);
         String output = myStringBuffer.toString();
-        myCurrent.stream.println(output);
-        /* Note: there's little point in checking for an output error.  We
-           can't put the trace in the log, and there's little chance the user
-           would see it in the trace buffer.  So we ignore it, with regret. */
-
-        myCurrentSize += output.length() + LINE_SEPARATOR_LENGTH;
-        if (myCurrentSize > myMaxSize) {
-            rolloverLogFile("This log is full.");
-        } else if (myNextRolloverTime != 0 &&
-                   myNextRolloverTime < message.timestamp()) {
-            do {
-                myNextRolloverTime += myRolloverFrequency;
-            } while (myNextRolloverTime < message.timestamp());
-            rolloverLogFile("The time has come for a new log file.");
+        if (logToStderr) {
+            System.err.println(output);
+        } else {
+            myCurrent.stream.println(output);
+            /* Note: there's little point in checking for an output error.  We
+               can't put the trace in the log, and there's little chance the user
+               would see it in the trace buffer.  So we ignore it, with regret. */
+
+            myCurrentSize += output.length() + LINE_SEPARATOR_LENGTH;
+            if (myCurrentSize > myMaxSize) {
+                rolloverLogFile("This log is full.");
+            } else if (myNextRolloverTime != 0 &&
+                       myNextRolloverTime < message.timestamp()) {
+                do {
+                    myNextRolloverTime += myRolloverFrequency;
+                } while (myNextRolloverTime < message.timestamp());
+                rolloverLogFile("The time has come for a new log file.");
+            }
         }
     }
 
@@ -294,6 +301,13 @@ private void changeTag(String value) {
         myPending.setTag(value);
     }
 
+    /**
+     * Sets the tracing log to output to stderr if the user so desires.
+     */
+    private void changeLogToStderr(String value) {
+        logToStderr = Boolean.parseBoolean(value);
+    }
+
     /**
      * The meaning of changeWrite is complicated.  Here are the cases when it's
      * used to turn writing ON.
@@ -510,6 +524,8 @@ public synchronized boolean setConfiguration(String name, String value) {
             changeRollover(value);
         } else if (name.equalsIgnoreCase("versions")) {
             changeVersionFileHandling(value);
+        } else if (name.equalsIgnoreCase("stderr")) {
+            changeLogToStderr(value);
         } else if (name.equalsIgnoreCase("reopen")) {
             reopen(value);
         } else {