Add feature to disable loading of Log implementations from the TCCL.

git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/logging/trunk@370030 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/commons/logging/impl/LogFactoryImpl.java

@@ -159,6 +159,11 @@ public class LogFactoryImpl extends LogFactory {
 
     // ----------------------------------------------------- Instance Variables
 
+    /**
+     * Determines whether logging classes should be loaded using the thread-context
+     * classloader, or via the classloader that loaded this LogFactoryImpl class.
+     */
+    private boolean useTCCL = true;
 
     /**
      * The string prefixed to every message output by the logDiagnostic method.
@@ -376,6 +381,10 @@ public class LogFactoryImpl extends LogFactory {
             attributes.put(name, value);
         }
         
+        if (name.equals(TCCL_KEY)) {
+            useTCCL = Boolean.valueOf(value.toString()).booleanValue();
+        }
+
     }
 
 
@@ -699,7 +708,6 @@ public class LogFactoryImpl extends LogFactory {
         String specifiedLogClassName = findUserSpecifiedLogClassName();
 
         if (specifiedLogClassName != null) {
-            // note: createLogFromClass never returns null..
             result = createLogFromClass(specifiedLogClassName,
                                         logCategory,
                                         true);
@@ -969,9 +977,14 @@ public class LogFactoryImpl extends LogFactory {
      * 
      */
     private ClassLoader getBaseClassLoader() throws LogConfigurationException {
-        ClassLoader contextClassLoader = getContextClassLoader();
         ClassLoader thisClassLoader = getClassLoader(LogFactoryImpl.class);
         
+        if (useTCCL == false) {
+            return thisClassLoader;
+        }
+
+        ClassLoader contextClassLoader = getContextClassLoader();
+
         ClassLoader baseClassLoader = getLowestClassLoader(
                 contextClassLoader, thisClassLoader);