JAVA-2800: Exclude SLF4J from mapper-processor dependencies

olim7t · olim7t · commit 505c0b1c568e · 2020-07-20T15:57:29.000-07:00
diff --git a/changelog/README.md b/changelog/README.md
@@ -4,6 +4,7 @@
 
 ### 4.8.0 (in progress)
 
+- [bug] JAVA-2800: Exclude SLF4J from mapper-processor dependencies
 - [new feature] JAVA-2819: Add DriverConfigLoader.fromString
 - [improvement] JAVA-2431: Set all occurrences when bound variables are used multiple times
 - [improvement] JAVA-2829: Log protocol negotiation messages at DEBUG level
diff --git a/mapper-processor/pom.xml b/mapper-processor/pom.xml
@@ -40,6 +40,20 @@
     <dependency>
       <groupId>com.datastax.oss</groupId>
       <artifactId>java-driver-mapper-runtime</artifactId>
+      <exclusions>
+        <!--
+          Exclude the dependency to SLF4J, otherwise this causes a warning when the processor is
+          configured with -processorpath, because no SLF4J backend is present (JAVA-2800).
+
+          Note however that some of the code generated by the processor does reference SLF4J types
+          (see LoggingGenerator). In those cases we have to resort to ClassName.get(String, String)
+          instead of using the SLF4J classes directly.
+        -->
+        <exclusion>
+          <groupId>org.slf4j</groupId>
+          <artifactId>slf4j-api</artifactId>
+        </exclusion>
+      </exclusions>
     </dependency>
     <dependency>
       <groupId>com.datastax.oss</groupId>
diff --git a/mapper-processor/src/main/java/com/datastax/oss/driver/internal/mapper/processor/DefaultProcessorContext.java b/mapper-processor/src/main/java/com/datastax/oss/driver/internal/mapper/processor/DefaultProcessorContext.java
@@ -16,7 +16,6 @@
 package com.datastax.oss.driver.internal.mapper.processor;
 
 import com.datastax.oss.driver.internal.core.context.DefaultDriverContext;
-import com.datastax.oss.driver.internal.core.util.concurrent.CycleDetector;
 import com.datastax.oss.driver.internal.core.util.concurrent.LazyReference;
 import com.datastax.oss.driver.internal.mapper.processor.dao.LoggingGenerator;
 import com.datastax.oss.driver.internal.mapper.processor.entity.DefaultEntityFactory;
@@ -29,14 +28,11 @@
 /** This follows the same principles as {@link DefaultDriverContext}. */
 public class DefaultProcessorContext implements ProcessorContext {
 
-  private final CycleDetector cycleDetector =
-      new CycleDetector("Detected cycle in context initialization");
-
   private final LazyReference<CodeGeneratorFactory> codeGeneratorFactoryRef =
-      new LazyReference<>("codeGeneratorFactory", this::buildCodeGeneratorFactory, cycleDetector);
+      new LazyReference<>(this::buildCodeGeneratorFactory);
 
   private final LazyReference<EntityFactory> entityFactoryRef =
-      new LazyReference<>("entityFactory", this::buildEntityFactory, cycleDetector);
+      new LazyReference<>(this::buildEntityFactory);
 
   private final DecoratedMessager messager;
   private final Types typeUtils;
diff --git a/mapper-processor/src/main/java/com/datastax/oss/driver/internal/mapper/processor/dao/LoggingGenerator.java b/mapper-processor/src/main/java/com/datastax/oss/driver/internal/mapper/processor/dao/LoggingGenerator.java
@@ -21,10 +21,14 @@
 import com.squareup.javapoet.MethodSpec;
 import com.squareup.javapoet.TypeSpec;
 import javax.lang.model.element.Modifier;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 public class LoggingGenerator {
+
+  // Reference these types by name to avoid a compile-time dependency to SFL4J
+  private static final ClassName LOGGER_FACTORY_CLASS_NAME =
+      ClassName.get("org.slf4j", "LoggerFactory");
+  private static final ClassName LOGGER_CLASS_NAME = ClassName.get("org.slf4j", "Logger");
+
   private final boolean logsEnabled;
 
   public LoggingGenerator(boolean logsEnabled) {
@@ -45,12 +49,8 @@ public void addLoggerField(TypeSpec.Builder classBuilder, ClassName className) {
     if (logsEnabled) {
       classBuilder.addField(
           FieldSpec.builder(
-                  ClassName.get(Logger.class),
-                  "LOG",
-                  Modifier.PRIVATE,
-                  Modifier.FINAL,
-                  Modifier.STATIC)
-              .initializer("$T.getLogger($T.class)", LoggerFactory.class, className)
+                  LOGGER_CLASS_NAME, "LOG", Modifier.PRIVATE, Modifier.FINAL, Modifier.STATIC)
+              .initializer("$T.getLogger($T.class)", LOGGER_FACTORY_CLASS_NAME, className)
               .build());
     }
   }
