From c92e43cf4d917a9a5bf0eb04e94bee5f38a0a6d2 Mon Sep 17 00:00:00 2001
From: Benjamin Bentmann <bentmann@sonatype.com>
Date: Thu, 1 May 2014 20:36:12 +0200
Subject: [PATCH] Bug 433942 - Allow easy booting of Aether in Sisu when SLF4J
 is not around

Introduced provider component to conditionally pick impl based on classpath
---
 .../internal/impl/LoggerFactoryProvider.java  | 55 +++++++++++++++++++
 .../impl/slf4j/Slf4jLoggerFactory.java        |  2 +-
 2 files changed, 56 insertions(+), 1 deletion(-)
 create mode 100644 aether-impl/src/main/java/org/eclipse/aether/internal/impl/LoggerFactoryProvider.java

diff --git a/aether-impl/src/main/java/org/eclipse/aether/internal/impl/LoggerFactoryProvider.java b/aether-impl/src/main/java/org/eclipse/aether/internal/impl/LoggerFactoryProvider.java
new file mode 100644
index 00000000..168cb9f3
--- /dev/null
+++ b/aether-impl/src/main/java/org/eclipse/aether/internal/impl/LoggerFactoryProvider.java
@@ -0,0 +1,55 @@
+/*******************************************************************************
+ * Copyright (c) 2014 Sonatype, Inc.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Sonatype, Inc. - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.aether.internal.impl;
+
+import javax.inject.Inject;
+import javax.inject.Named;
+import javax.inject.Provider;
+import javax.inject.Singleton;
+
+import org.eclipse.aether.spi.log.LoggerFactory;
+import org.eclipse.aether.spi.log.NullLoggerFactory;
+
+/**
+ * Helps Sisu-based applications to pick the right logger factory depending on the classpath.
+ */
+@Named
+@Singleton
+public class LoggerFactoryProvider
+    implements Provider<LoggerFactory>
+{
+
+    @Inject
+    @Named( "slf4j" )
+    private Provider<LoggerFactory> slf4j;
+
+    public LoggerFactory get()
+    {
+        try
+        {
+            LoggerFactory factory = slf4j.get();
+            if ( factory != null )
+            {
+                return factory;
+            }
+        }
+        catch ( LinkageError e )
+        {
+            // fall through
+        }
+        catch ( RuntimeException e )
+        {
+            // fall through
+        }
+        return NullLoggerFactory.INSTANCE;
+    }
+
+}
diff --git a/aether-impl/src/main/java/org/eclipse/aether/internal/impl/slf4j/Slf4jLoggerFactory.java b/aether-impl/src/main/java/org/eclipse/aether/internal/impl/slf4j/Slf4jLoggerFactory.java
index 31328d05..763d67fc 100644
--- a/aether-impl/src/main/java/org/eclipse/aether/internal/impl/slf4j/Slf4jLoggerFactory.java
+++ b/aether-impl/src/main/java/org/eclipse/aether/internal/impl/slf4j/Slf4jLoggerFactory.java
@@ -24,7 +24,7 @@ import org.slf4j.spi.LocationAwareLogger;
 /**
  * A logger factory that delegates to <a href="http://www.slf4j.org/">SLF4J</a> logging.
  */
-@Named
+@Named( "slf4j" )
 public class Slf4jLoggerFactory
     implements LoggerFactory, Service
 {
-- 
GitLab