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>