Description: Provide built-in injection of SLF4J loggers
Author: Stuart McCulloch <mcculls@gmail.com>
Bug-Google: http://code.google.com/p/google-guice/issues/detail?id=492
Last-Update: 2014-11-07

diff --git a/common.xml b/common.xml
index a23eb90..2d3d9b3 100644
--- a/common.xml
+++ b/common.xml
@@ -44,6 +44,10 @@
 
     <property name="Export-Package" value="!${module}.internal.*,${module}.*;version=${api.version}"/>
 
+    <condition property="DynamicImport-Package" value="org.slf4j">
+      <equals arg1="${module}" arg2="com.google.inject"/>
+    </condition>
+
     <condition property="Eclipse-ExtensibleAPI" value="true">
       <equals arg1="${module}" arg2="com.google.inject"/>
     </condition>
diff --git a/core/pom.xml b/core/pom.xml
index 33e6dcc..edfa724 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -15,6 +15,12 @@
 
   <dependencies>
     <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-api</artifactId>
+      <version>1.6.4</version>
+      <optional>true</optional>
+    </dependency>
+    <dependency>
       <groupId>javax.inject</groupId>
       <artifactId>javax.inject</artifactId>
     </dependency>
@@ -91,6 +97,12 @@
         <artifactId>maven-surefire-plugin</artifactId>
         <configuration>
           <!--
+           | Run core tests without SLF4J on the classpath
+          -->
+          <classpathDependencyExcludes>
+            <exclude>org.slf4j:slf4j-api</exclude>
+          </classpathDependencyExcludes>
+          <!--
            | Temporarily excluded tests
           -->
           <excludes>
@@ -113,6 +125,7 @@
             <Bundle-Name>${project.artifactId}$(if;$(classes;NAMED;*.MethodAspect);; (no_aop))</Bundle-Name>
             <Import-Package>!net.sf.cglib.*,!org.objectweb.asm.*,!com.google.inject.*,*</Import-Package>
             <Eclipse-ExtensibleAPI>true</Eclipse-ExtensibleAPI>
+            <DynamicImport-Package>org.slf4j</DynamicImport-Package>
           </instructions>
         </configuration>
       </plugin>
diff --git a/core/src/com/google/inject/internal/InjectorShell.java b/core/src/com/google/inject/internal/InjectorShell.java
index 6100879..56b13b3 100644
--- a/core/src/com/google/inject/internal/InjectorShell.java
+++ b/core/src/com/google/inject/internal/InjectorShell.java
@@ -251,6 +251,15 @@ final class InjectorShell {
         new ProviderInstanceBindingImpl<Logger>(injector, key,
             SourceProvider.UNKNOWN_SOURCE, loggerFactory, Scoping.UNSCOPED,
             loggerFactory, ImmutableSet.<InjectionPoint>of()));
+
+    try {
+      Key<org.slf4j.Logger> slf4jKey = Key.get(org.slf4j.Logger.class);
+      SLF4JLoggerFactory slf4jLoggerFactory = new SLF4JLoggerFactory(injector);
+      injector.state.putBinding(slf4jKey,
+          new ProviderInstanceBindingImpl<org.slf4j.Logger>(injector, slf4jKey,
+              SourceProvider.UNKNOWN_SOURCE, slf4jLoggerFactory, Scoping.UNSCOPED,
+              slf4jLoggerFactory, ImmutableSet.<InjectionPoint>of()));
+    } catch (Throwable e) {}
   }
 
   private static class LoggerFactory implements InternalFactory<Logger>, Provider<Logger> {
@@ -270,6 +279,44 @@ final class InjectorShell {
     }
   }
   
+  private static class SLF4JLoggerFactory implements InternalFactory<org.slf4j.Logger>, Provider<org.slf4j.Logger> {
+    private final Injector injector;
+
+    private org.slf4j.ILoggerFactory loggerFactory;
+
+    SLF4JLoggerFactory(Injector injector) {
+      this.injector = injector;
+    }
+
+    org.slf4j.ILoggerFactory loggerFactory() {
+      if (loggerFactory == null) {
+        try {
+          loggerFactory = injector.getInstance(org.slf4j.ILoggerFactory.class);
+        } catch (Throwable e) {}
+        if (loggerFactory == null) {
+          loggerFactory = org.slf4j.LoggerFactory.getILoggerFactory();
+        }
+      }
+      return loggerFactory;
+    }
+
+    public org.slf4j.Logger get(Errors errors, InternalContext context, Dependency<?> dependency, boolean linked) {
+      InjectionPoint injectionPoint = dependency.getInjectionPoint();
+      if (injectionPoint != null) {
+        return loggerFactory().getLogger(injectionPoint.getMember().getDeclaringClass().getName());
+      }
+      return loggerFactory().getLogger(org.slf4j.Logger.ROOT_LOGGER_NAME);
+    }
+
+    public org.slf4j.Logger get() {
+      return loggerFactory().getLogger(org.slf4j.Logger.ROOT_LOGGER_NAME);
+    }
+
+    public String toString() {
+      return "Provider<org.slf4j.Logger>";
+    }
+  }
+
   private static void bindStage(InjectorImpl injector, Stage stage) {
     Key<Stage> key = Key.get(Stage.class);
     InstanceBindingImpl<Stage> stageBinding = new InstanceBindingImpl<Stage>(
diff --git a/extensions/persist/pom.xml b/extensions/persist/pom.xml
index a560f38..e909927 100644
--- a/extensions/persist/pom.xml
+++ b/extensions/persist/pom.xml
@@ -29,7 +29,7 @@
     <dependency>
       <groupId>org.slf4j</groupId>
       <artifactId>slf4j-simple</artifactId>
-      <version>1.6.1</version>
+      <version>1.6.4</version>
       <scope>test</scope>
     </dependency>
     <dependency>
diff --git a/lib/build/slf4j-api-1.6.4.jar b/lib/build/slf4j-api-1.6.4.jar
new file mode 100644
index 0000000..76ef305
Binary files /dev/null and b/lib/build/slf4j-api-1.6.4.jar differ
diff --git a/pom.xml b/pom.xml
index 37305d0..5834d49 100644
--- a/pom.xml
+++ b/pom.xml
@@ -283,7 +283,7 @@ See the Apache License Version 2.0 for the specific language governing permissio
         </plugin>
         <plugin>
           <artifactId>maven-surefire-plugin</artifactId>
-          <version>2.5</version>
+          <version>2.6</version>
           <configuration>
             <redirectTestOutputToFile>true</redirectTestOutputToFile>
             <!--<argLine>-Dguice_include_stack_traces=OFF</argLine>-->