add tests for DirectBufferUtils

hermes-consumers/src/main/java/pl/allegro/tech/hermes/consumers/consumer/batch/DirectBufferUtils.java

@@ -15,40 +15,40 @@ class DirectBufferUtils {
     static {
         DirectBufferCleaner cleaner;
         try {
-            cleaner = new Java11DirectBufferCleaner();
+            cleaner = new DirectBufferCleaner();
         } catch (ReflectiveOperationException e) {
             cleaner = null;
         }
         CLEANER = cleaner;
     }
 
+    static boolean supportsReleasing() {
+        return CLEANER != null;
+    }
+
+
     static void release(ByteBuffer buffer) {
         try {
-            if (CLEANER != null && buffer.isDirect()) {
+            if (supportsReleasing() && buffer.isDirect()) {
                 CLEANER.clean(buffer);
             }
         } catch (ReflectiveOperationException e) {
             logger.warn("Releasing ByteBuffer failed", e);
         }
     }
 
-    private interface DirectBufferCleaner {
-        void clean(ByteBuffer buffer) throws ReflectiveOperationException;
-    }
-
-    static class Java11DirectBufferCleaner implements DirectBufferCleaner {
+    static class DirectBufferCleaner {
         private final Object unsafe;
         private final Method invokeCleaner;
 
-        Java11DirectBufferCleaner() throws ReflectiveOperationException {
+        DirectBufferCleaner() throws ReflectiveOperationException {
             Class<?> clazz = Class.forName("sun.misc.Unsafe");
             Field field = clazz.getDeclaredField("theUnsafe");
             field.setAccessible(true);
             unsafe = field.get(null);
             invokeCleaner = clazz.getMethod("invokeCleaner", ByteBuffer.class);
         }
 
-        @Override
         public void clean(ByteBuffer buffer) throws ReflectiveOperationException {
             invokeCleaner.invoke(unsafe, buffer);
         }

hermes-consumers/src/test/java/pl/allegro/tech/hermes/consumers/consumer/batch/DirectBufferUtilsTest.java

@@ -0,0 +1,31 @@
+package pl.allegro.tech.hermes.consumers.consumer.batch;
+
+import org.assertj.core.api.Assertions;
+import org.junit.Test;
+
+import java.nio.ByteBuffer;
+import static org.junit.Assert.assertEquals;
+
+public class DirectBufferUtilsTest {
+    @Test
+    public void shouldReleaseDirectByteBuffer() {
+        // given
+        ByteBuffer buffer = ByteBuffer.allocateDirect(128);
+
+        // when & then
+        assertEquals(DirectBufferUtils.supportsReleasing(), true);
+        Assertions.assertThatCode(() -> DirectBufferUtils.release(buffer))
+                .doesNotThrowAnyException();
+    }
+
+    @Test
+    public void shouldNotReleaseByteBuffer() {
+        // given
+        ByteBuffer buffer = ByteBuffer.allocate(128);
+
+        // when & then
+        assertEquals(DirectBufferUtils.supportsReleasing(), true);
+        Assertions.assertThatCode(() -> DirectBufferUtils.release(buffer))
+                .doesNotThrowAnyException();
+    }
+}