Add a mechanism to use a proxy. The default impl will first look for

a logger package, and preferably use a specialized factory, which
can provide better integration with the real logger.

The introspection is ok, but it's limited and complex.

Also, switch to SimpleLog by default - which is almost the same as
using System.err.println(). If common logging requires the user to set
properties and configurations to get the same behavior as System.err(),
why would anyone use it ?


git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/logging/trunk@138867 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -1,7 +1,7 @@
 /*
- * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//logging/src/java/org/apache/commons/logging/impl/LogFactoryImpl.java,v 1.3 2002/02/14 03:48:44 craigmcc Exp $
- * $Revision: 1.3 $
- * $Date: 2002/02/14 03:48:44 $
+ * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//logging/src/java/org/apache/commons/logging/impl/LogFactoryImpl.java,v 1.4 2002/02/15 05:42:35 costin Exp $
+ * $Revision: 1.4 $
+ * $Date: 2002/02/15 05:42:35 $
  *
  * ====================================================================
  *
@@ -104,12 +104,11 @@ import org.apache.commons.logging.LogSource;
  *
  * @author Rod Waldhoff
  * @author Craig R. McClanahan
- * @version $Revision: 1.3 $ $Date: 2002/02/14 03:48:44 $
+ * @version $Revision: 1.4 $ $Date: 2002/02/15 05:42:35 $
  */
 
 public class LogFactoryImpl extends LogFactory {
 
-
     // ----------------------------------------------------------- Constructors
 
 
@@ -117,20 +116,22 @@ public class LogFactoryImpl extends LogFactory {
      * Public no-arguments constructor required by the lookup mechanism.
      */
     public LogFactoryImpl() {
-
         super();
-
+        guessConfig();
     }
 
 
     // ----------------------------------------------------- Manifest Constants
 
 
+    // Defaulting to NullLogger means important messages will be lost if
+    // no other logger is available. This is as bad as having a catch() and
+    // ignoring the exception because 'it can't happen'
     /**
      * The fully qualified name of the default {@link Log} implementation.
      */
     public static final String LOG_DEFAULT =
-        "org.apache.commons.logging.impl.NoOpLog";
+        "org.apache.commons.logging.impl.SimpleLog";
 
 
     /**
@@ -173,6 +174,8 @@ public class LogFactoryImpl extends LogFactory {
     protected Constructor logConstructor = null;
 
 
+    protected LogFactory proxyFactory=null;
+
     /**
      * The signature of the Constructor to be used.
      */
@@ -204,7 +207,8 @@ public class LogFactoryImpl extends LogFactory {
      * @param name Name of the attribute to return
      */
     public Object getAttribute(String name) {
-
+        if( proxyFactory != null )
+            return proxyFactory.getAttribute( name );
         return (attributes.get(name));
 
     }
@@ -216,6 +220,8 @@ public class LogFactoryImpl extends LogFactory {
      * length array is returned.
      */
     public String[] getAttributeNames() {
+        if( proxyFactory != null )
+            return proxyFactory.getAttributeNames();
 
         Vector names = new Vector();
         Enumeration keys = attributes.keys();
@@ -241,7 +247,10 @@ public class LogFactoryImpl extends LogFactory {
      *  instance cannot be returned
      */
     public Log getInstance(Class clazz)
-        throws LogConfigurationException {
+        throws LogConfigurationException
+    {
+        if( proxyFactory != null )
+            return proxyFactory.getInstance(clazz);
 
         return (getInstance(clazz.getName()));
 
@@ -266,7 +275,10 @@ public class LogFactoryImpl extends LogFactory {
      *  instance cannot be returned
      */
     public Log getInstance(String name)
-        throws LogConfigurationException {
+        throws LogConfigurationException
+    {
+        if( proxyFactory != null )
+            return proxyFactory.getInstance(name);
 
         Log instance = (Log) instances.get(name);
         if (instance == null) {
@@ -286,6 +298,8 @@ public class LogFactoryImpl extends LogFactory {
      * class loader would prevent garbage collection.
      */
     public void release() {
+        if( proxyFactory != null )
+            proxyFactory.release();
 
         instances.clear();
 
@@ -299,9 +313,10 @@ public class LogFactoryImpl extends LogFactory {
      * @param name Name of the attribute to remove
      */
     public void removeAttribute(String name) {
+        if( proxyFactory != null )
+            proxyFactory.removeAttribute(name);
 
         attributes.remove(name);
-
     }
 
 
@@ -315,6 +330,8 @@ public class LogFactoryImpl extends LogFactory {
      *  to remove any setting for this attribute
      */
     public void setAttribute(String name, Object value) {
+        if( proxyFactory != null )
+            proxyFactory.setAttribute(name,value);
 
         if (value == null) {
             attributes.remove(name);
@@ -406,6 +423,20 @@ public class LogFactoryImpl extends LogFactory {
 
     }
 
+    protected void guessConfig() {
+        if( isLog4JAvailable() ) {
+            try {
+                Class proxyClass=findClassLoader().
+                    loadClass( "org.apache.commons.logging.Log4jFactory" );
+                proxyFactory=(LogFactory)proxyClass.newInstance();
+            } catch( Throwable t ) {
+                proxyFactory=null;
+            }
+        }
+        // other logger specific initialization
+        // ...
+    }
+    
 
     /**
      * Is <em>JDK 1.4 or later</em> logging available?