JAVA-1761: Add OSGi descriptors

Motivation:

To enable the driver to be used in OSGi containers.

Modifications:

Use maven-bundle-plugin to add OSGi information to the generated
MANIFEST.MF.

Shaded jctools instead of using netty-shaded for MpscLinkedAtomicQueue
in DefaultWriteCoalescer.  This was required because netty does not
export its shaded jctools packages in its Export-Package definition.

Add SessionBuilder.withClassLoader to allow overriding ClassLoader
used to load classes from config which is useful for OSGi.

Add OSGi integration tests.

Make all dependency versions properties so they may be passed to
failsafe plugin for use in OSGi tests.

Result:

The driver now supports OSGi.

changelog/README.md

@@ -4,6 +4,7 @@
 
 ### 4.0.0-alpha4 (in progress)
 
+- [new feature] JAVA-1761: Add OSGi descriptors
 - [bug] JAVA-1560: Correctly propagate policy initialization errors
 - [improvement] JAVA-1865: Add RelationMetadata.getPrimaryKey()
 - [improvement] JAVA-1862: Add ConsistencyLevel.isDcLocal and isSerial

core/pom.xml

@@ -15,7 +15,9 @@
     limitations under the License.
 
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <parent>
@@ -25,7 +27,7 @@
   </parent>
 
   <artifactId>java-driver-core</artifactId>
-  <packaging>jar</packaging>
+  <packaging>bundle</packaging>
 
   <name>DataStax Java driver for Apache Cassandra(R) - core</name>
 
@@ -75,6 +77,10 @@
       <groupId>org.slf4j</groupId>
       <artifactId>slf4j-api</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.jctools</groupId>
+      <artifactId>jctools-core</artifactId>
+    </dependency>
     <dependency>
       <groupId>io.dropwizard.metrics</groupId>
       <artifactId>metrics-core</artifactId>
@@ -154,6 +160,75 @@
           </properties>
         </configuration>
       </plugin>
+      <plugin>
+        <groupId>org.apache.felix</groupId>
+        <artifactId>maven-bundle-plugin</artifactId>
+        <configuration>
+          <manifestLocation>${project.build.outputDirectory}/META-INF</manifestLocation>
+          <instructions>
+            <Bundle-SymbolicName>com.datastax.oss.driver.core</Bundle-SymbolicName>
+            <!-- Allow importing code from other packages (so reflection-based loading of policies works) -->
+            <DynamicImport-Package>*</DynamicImport-Package>
+            <!-- Don't include JNR packages since some JNR modules are not OSGi bundles,
+                 jcip because its not an OSGi bundle, jctools because its shaded.
+                 Import sun.misc as jctools does this. -->
+            <Import-Package>
+              !net.jcip.annotations,!jnr.*,!org.jctools.*,sun.misc;resolution:=optional,*
+            </Import-Package>
+            <!-- Explicitly declare shaded jctools packages since this isn't covered by shade plugin -->
+            <Export-Package>
+              com.datastax.oss.driver.*.core.*,
+              com.datastax.oss.driver.shaded.jctools.util;version="${project.version}";uses:="sun.misc",
+              com.datastax.oss.driver.shaded.jctools.queues;version="${project.version}";uses:="com.datastax.oss.driver.shaded.jctools.queues.spec",
+              com.datastax.oss.driver.shaded.jctools.queues.spec;version="${project.version}",
+              com.datastax.oss.driver.shaded.jctools.queues.atomic;version="${project.version}";uses:="com.datastax.oss.driver.shaded.jctools.queues,com.datastax.oss.driver.shaded.jctools.queues.spec",
+              com.datastax.oss.driver.shaded.jctools.maps;version="${project.version}"
+            </Export-Package>
+          </instructions>
+          <!--
+          Prevent customized manifest entries from the project's maven-jar-plugin configuration from being read, see
+          http://apache-felix.18485.x6.nabble.com/how-lt-manifestLocation-gt-is-used-in-maven-bundle-plugin-td4835566.html
+          -->
+          <archive>
+            <forced>true</forced>
+          </archive>
+        </configuration>
+      </plugin>
+      <!-- shade jctools -->
+      <plugin>
+        <artifactId>maven-shade-plugin</artifactId>
+        <executions>
+          <execution>
+            <phase>package</phase>
+            <goals>
+              <goal>shade</goal>
+            </goals>
+            <configuration>
+              <artifactSet>
+                <includes>
+                  <include>org.jctools:jctools-core</include>
+                </includes>
+              </artifactSet>
+              <relocations>
+                <relocation>
+                  <pattern>org.jctools</pattern>
+                  <shadedPattern>com.datastax.oss.driver.shaded.jctools</shadedPattern>
+                </relocation>
+              </relocations>
+              <transformers>
+                <transformer
+                        implementation="org.apache.maven.plugins.shade.resource.DontIncludeResourceTransformer">
+                  <resources>
+                    <resource>META-INF/maven/org.jctools/jctools-core/pom.properties</resource>
+                    <resource>META-INF/maven/org.jctools/jctools-core/pom.xml</resource>
+                  </resources>
+                </transformer>
+              </transformers>
+              <promoteTransitiveDependencies>true</promoteTransitiveDependencies>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
     </plugins>
   </build>
 </project>

core/src/main/java/com/datastax/oss/driver/api/core/session/SessionBuilder.java

@@ -68,6 +68,7 @@ public abstract class SessionBuilder<SelfT extends SessionBuilder, SessionT> {
   protected RequestTracker requestTracker;
   private ImmutableMap.Builder<String, Predicate<Node>> nodeFilters = ImmutableMap.builder();
   protected CqlIdentifier keyspace;
+  private ClassLoader classLoader = null;
 
   /**
    * Sets the configuration loader to use.
@@ -222,6 +223,20 @@ public SelfT withKeyspace(String keyspaceName) {
     return withKeyspace(CqlIdentifier.fromCql(keyspaceName));
   }
 
+  /**
+   * The {@link ClassLoader} to use to reflectively load class names defined in configuration.
+   *
+   * <p>This is typically only needed when using OSGi or other in environments where there are
+   * complex class loading requirements.
+   *
+   * <p>If null, the driver attempts to use {@link Thread#getContextClassLoader()} of the current
+   * thread or the same {@link ClassLoader} that loaded the core driver classes.
+   */
+  public SelfT withClassLoader(ClassLoader classLoader) {
+    this.classLoader = classLoader;
+    return self;
+  }
+
   /**
    * Creates the session with the options set by this builder.
    *
@@ -269,7 +284,8 @@ protected final CompletionStage<CqlSession> buildDefaultSessionAsync() {
                   nodeStateListener,
                   schemaChangeListener,
                   requestTracker,
-                  nodeFilters.build()),
+                  nodeFilters.build(),
+                  classLoader),
           contactPoints,
           keyspace);
 
@@ -290,14 +306,16 @@ protected DriverContext buildContext(
       NodeStateListener nodeStateListener,
       SchemaChangeListener schemaChangeListener,
       RequestTracker requestTracker,
-      Map<String, Predicate<Node>> nodeFilters) {
+      Map<String, Predicate<Node>> nodeFilters,
+      ClassLoader classLoader) {
     return new DefaultDriverContext(
         configLoader,
         typeCodecs,
         nodeStateListener,
         schemaChangeListener,
         requestTracker,
-        nodeFilters);
+        nodeFilters,
+        classLoader);
   }
 
   private static <T> T buildIfNull(T value, Supplier<T> builder) {

core/src/main/java/com/datastax/oss/driver/internal/core/channel/DefaultWriteCoalescer.java

@@ -22,7 +22,6 @@
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelPromise;
 import io.netty.channel.EventLoop;
-import io.netty.util.internal.shaded.org.jctools.queues.atomic.MpscLinkedAtomicQueue;
 import java.util.HashSet;
 import java.util.Queue;
 import java.util.Set;
@@ -31,6 +30,7 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import net.jcip.annotations.ThreadSafe;
+import org.jctools.queues.atomic.MpscLinkedAtomicQueue;
 
 /**
  * Default write coalescing strategy.

core/src/main/java/com/datastax/oss/driver/internal/core/context/DefaultDriverContext.java

@@ -189,14 +189,16 @@ public class DefaultDriverContext implements InternalDriverContext {
   private final SchemaChangeListener schemaChangeListenerFromBuilder;
   private final RequestTracker requestTrackerFromBuilder;
   private final Map<String, Predicate<Node>> nodeFiltersFromBuilder;
+  private final ClassLoader classLoader;
 
   public DefaultDriverContext(
       DriverConfigLoader configLoader,
       List<TypeCodec<?>> typeCodecs,
       NodeStateListener nodeStateListener,
       SchemaChangeListener schemaChangeListener,
       RequestTracker requestTracker,
-      Map<String, Predicate<Node>> nodeFilters) {
+      Map<String, Predicate<Node>> nodeFilters,
+      ClassLoader classLoader) {
     this.config = configLoader.getInitialConfig();
     this.configLoader = configLoader;
     DriverConfigProfile defaultProfile = config.getDefaultProfile();
@@ -223,6 +225,7 @@ public DefaultDriverContext(
         new LazyReference<>(
             "requestTracker", () -> buildRequestTracker(requestTrackerFromBuilder), cycleDetector);
     this.nodeFiltersFromBuilder = nodeFilters;
+    this.classLoader = classLoader;
   }
 
   protected Map<String, LoadBalancingPolicy> buildLoadBalancingPolicies() {
@@ -671,6 +674,11 @@ public Predicate<Node> nodeFilter(String profileName) {
     return nodeFiltersFromBuilder.get(profileName);
   }
 
+  @Override
+  public ClassLoader classLoader() {
+    return classLoader;
+  }
+
   @Override
   public CodecRegistry codecRegistry() {
     return codecRegistry;

core/src/main/java/com/datastax/oss/driver/internal/core/context/InternalDriverContext.java

@@ -95,4 +95,11 @@ public interface InternalDriverContext extends DriverContext {
    * {@code null}.
    */
   Predicate<Node> nodeFilter(String profileName);
+
+  /**
+   * The {@link ClassLoader} to use to reflectively load class names defined in configuration. If
+   * null, the driver attempts to use {@link Thread#getContextClassLoader()} of the current thread
+   * or {@link com.datastax.oss.driver.internal.core.util.Reflection}'s {@link ClassLoader}.
+   */
+  ClassLoader classLoader();
 }

core/src/main/java/com/datastax/oss/driver/internal/core/loadbalancing/DefaultLoadBalancingPolicy.java

@@ -298,7 +298,7 @@ private static Predicate<Node> getFilterFromConfig(DriverContext context, String
         ? filterFromBuilder
         : (Predicate<Node>)
             Reflection.buildFromConfig(
-                    context,
+                    (InternalDriverContext) context,
                     profileName,
                     DefaultDriverOption.LOAD_BALANCING_FILTER_CLASS,
                     Predicate.class)

core/src/main/java/com/datastax/oss/driver/internal/core/util/Reflection.java

@@ -18,6 +18,7 @@
 import com.datastax.oss.driver.api.core.config.DriverConfigProfile;
 import com.datastax.oss.driver.api.core.config.DriverOption;
 import com.datastax.oss.driver.api.core.context.DriverContext;
+import com.datastax.oss.driver.internal.core.context.InternalDriverContext;
 import com.datastax.oss.driver.shaded.guava.common.base.Joiner;
 import com.datastax.oss.driver.shaded.guava.common.base.Preconditions;
 import com.datastax.oss.driver.shaded.guava.common.collect.ImmutableMap;
@@ -45,11 +46,14 @@ public class Reflection {
    *
    * @return null if the class does not exist.
    */
-  public static Class<?> loadClass(String className) {
+  public static Class<?> loadClass(ClassLoader classLoader, String className) {
     try {
-      ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
-      if (contextClassLoader != null) {
-        return Class.forName(className, true, contextClassLoader);
+      // If input classLoader is null, use current thread's ClassLoader, if that is null, use
+      // default (calling class') ClassLoader.
+      ClassLoader cl =
+          classLoader != null ? classLoader : Thread.currentThread().getContextClassLoader();
+      if (cl != null) {
+        return Class.forName(className, true, cl);
       } else {
         return Class.forName(className);
       }
@@ -80,7 +84,7 @@ public static Class<?> loadClass(String className) {
    *     configuration.
    */
   public static <T> Optional<T> buildFromConfig(
-      DriverContext context,
+      InternalDriverContext context,
       DriverOption classNameOption,
       Class<T> expectedSuperType,
       String... defaultPackages) {
@@ -116,7 +120,7 @@ public static <T> Optional<T> buildFromConfig(
    *     configuration, a single instance will be shared by all their entries.
    */
   public static <T> Map<String, T> buildFromConfigProfiles(
-      DriverContext context,
+      InternalDriverContext context,
       DriverOption rootOption,
       Class<T> expectedSuperType,
       String... defaultPackages) {
@@ -155,7 +159,7 @@ context, profileName, classOption(rootOption), expectedSuperType, defaultPackage
    *     constructor.
    */
   public static <T> Optional<T> buildFromConfig(
-      DriverContext context,
+      InternalDriverContext context,
       String profileName,
       DriverOption classNameOption,
       Class<T> expectedSuperType,
@@ -178,13 +182,13 @@ public static <T> Optional<T> buildFromConfig(
     Class<?> clazz = null;
     if (className.contains(".")) {
       LOG.debug("Building from fully-qualified name {}", className);
-      clazz = loadClass(className);
+      clazz = loadClass(context.classLoader(), className);
     } else {
       LOG.debug("Building from unqualified name {}", className);
       for (String defaultPackage : defaultPackages) {
         String qualifiedClassName = defaultPackage + "." + className;
         LOG.debug("Trying with default package {}", qualifiedClassName);
-        clazz = loadClass(qualifiedClassName);
+        clazz = loadClass(context.classLoader(), qualifiedClassName);
         if (clazz != null) {
           break;
         }
@@ -201,13 +205,13 @@ public static <T> Optional<T> buildFromConfig(
         configPath,
         expectedSuperType.getName());
 
-    Constructor<?> constructor;
+    Constructor<? extends T> constructor;
     Class<?>[] argumentTypes =
         (profileName == null)
             ? new Class<?>[] {DriverContext.class}
             : new Class<?>[] {DriverContext.class, String.class};
     try {
-      constructor = clazz.getConstructor(argumentTypes);
+      constructor = clazz.asSubclass(expectedSuperType).getConstructor(argumentTypes);
     } catch (NoSuchMethodException e) {
       throw new IllegalArgumentException(
           String.format(
@@ -217,11 +221,11 @@ public static <T> Optional<T> buildFromConfig(
     }
     try {
       @SuppressWarnings("JavaReflectionInvocation")
-      Object instance =
+      T instance =
           (profileName == null)
               ? constructor.newInstance(context)
               : constructor.newInstance(context, profileName);
-      return Optional.of(expectedSuperType.cast(instance));
+      return Optional.of(instance);
     } catch (Exception e) {
       // ITE just wraps an exception thrown by the constructor, get rid of it:
       Throwable cause = (e instanceof InvocationTargetException) ? e.getCause() : e;

core/src/test/java/com/datastax/oss/driver/internal/core/util/ReflectionTest.java

@@ -19,9 +19,9 @@
 
 import com.datastax.oss.driver.api.core.config.DefaultDriverOption;
 import com.datastax.oss.driver.api.core.config.DriverConfigProfile;
-import com.datastax.oss.driver.api.core.context.DriverContext;
 import com.datastax.oss.driver.api.core.specex.SpeculativeExecutionPolicy;
 import com.datastax.oss.driver.internal.core.config.typesafe.TypesafeDriverConfig;
+import com.datastax.oss.driver.internal.core.context.InternalDriverContext;
 import com.datastax.oss.driver.internal.core.specex.ConstantSpeculativeExecutionPolicy;
 import com.datastax.oss.driver.internal.core.specex.NoSpeculativeExecutionPolicy;
 import com.typesafe.config.ConfigFactory;
@@ -55,7 +55,7 @@ public void should_build_policies_per_profile() {
             + "    advanced.speculative-execution-policy.class = NoSpeculativeExecutionPolicy\n"
             + "  }\n"
             + "}\n";
-    DriverContext context = Mockito.mock(DriverContext.class);
+    InternalDriverContext context = Mockito.mock(InternalDriverContext.class);
     TypesafeDriverConfig config = new TypesafeDriverConfig(ConfigFactory.parseString(configSource));
     Mockito.when(context.config()).thenReturn(config);