QFS java shim:

* Change qfs-access to use java 9 and later finalizer style APIs.
* Retain compatibility with pre-java 9 versions by creating a new module qfs-access-pre-9 that uses the old finalizer style APIs.
* Update the build scripts to include the new module.
* Fix java 9 finalizer handling in qfs-access module.

Author: mikeov

src/java/javabuild.sh

@@ -100,12 +100,25 @@ until javac --release $min_supported_release -version >/dev/null 2>&1; do
     fi
     min_supported_release=$(expr $min_supported_release + 1)
 done
+if [ x"${qfs_access_profile-}" = x ]; then
+    if [ $min_supported_release -lt 9 ]; then
+        qfs_access_profile="qfs_access_java_pre_9"
+    else
+        qfs_access_profile="qfs_access_java_9"
+    fi
+fi
 min_supported_release=1.$min_supported_release
 
 echo "qfs_release_version = $qfs_release_version"
 echo "qfs_source_revision = $qfs_source_revision"
 echo "hadoop_qfs_profile  = $hadoop_qfs_profile"
 echo "test_build_data     = $test_build_data"
+echo "qfs_access_profile  = $qfs_access_profile"
+if [ x"$qfs_access_profile" = x'qfs_access_java_9' ]; then
+    qfs_access_project='qfs-access'
+else
+    qfs_access_project='qfs-access-pre-9'
+fi
 
 run_maven_exit_if_success() {
     set -x
@@ -125,11 +138,13 @@ mytry=0
 while true; do
     if [ x"$1" = x'--' ]; then
         shift
-        run_maven_exit_if_success ${1+"$@"}
+        run_maven_exit_if_success -P "$qfs_access_profile" ${1+"$@"}
     elif [ x"$hadoop_qfs_profile" = x'none' ]; then
-        run_maven_exit_if_success --projects qfs-access package
+        run_maven_exit_if_success -P "$qfs_access_profile" \
+            --projects "$qfs_access_project" package
     else
-        run_maven_exit_if_success -P "$hadoop_qfs_profile" \
+        run_maven_exit_if_success \
+            -P "$hadoop_qfs_profile","$qfs_access_profile" \
             -Dhadoop.release.version="$1" package
     fi
     mytry=$(expr $mytry + 1)

src/java/pom.xml

@@ -60,7 +60,6 @@ permissions and limitations under the License.
     </dependency>
   </dependencies>
   <modules>
-    <module>qfs-access</module>
     <module>hadoop-qfs</module>
   </modules>
   <profiles>
@@ -70,5 +69,17 @@ permissions and limitations under the License.
           <module>hadoop-qfs-2</module>
         </modules>
     </profile>
+    <profile>
+      <id>qfs_access_java_pre_9</id>
+        <modules>
+          <module>qfs-access-pre-9</module>
+        </modules>
+    </profile>
+    <profile>
+      <id>qfs_access_java_9</id>
+        <modules>
+          <module>qfs-access</module>
+        </modules>
+    </profile>
   </profiles>
 </project>

src/java/qfs-access-pre-9/pom.xml

@@ -0,0 +1 @@
+../qfs-access/pom.xml

src/java/qfs-access-pre-9/src/main/java/com/quantcast/qfs/access/BufferPool.java

@@ -0,0 +1 @@
+../../../../../../../../qfs-access/src/main/java/com/quantcast/qfs/access/BufferPool.java

src/java/qfs-access-9/src/main/java/com/quantcast/qfs/access/KfsAccess.java renamed to src/java/qfs-access-pre-9/src/main/java/com/quantcast/qfs/access/KfsAccess.java

@@ -22,44 +22,29 @@
  * License for the specific language governing permissions and limitations under
  * the License.
  *
- * \brief QFS access java 9 style cleanup.
+ * \brief Java wrappers to get to the KFS client.
  */
 package com.quantcast.qfs.access;
 
 import java.io.IOException;
-import java.lang.ref.Cleaner;
 
 final public class KfsAccess extends KfsAccessBase {
 
-    private static Cleaner cleaner = Cleaner.create();
-
-    static Cleaner.Cleanable registerCleanup(Object obj, Runnable action) {
-        return cleaner.register(obj, action);
-    }
-
-    private static void registerCleanupSelf(KfsAccess ka) {
-        // Ensure that the native resource is cleaned up when this object is
-        // garbage collected.
-        // Make sure that this and ka are not referenced by the cleaner closure
-        // otherwise it will never be cleaned up.
-        final long ptr = ka.getCPtr();
-        registerCleanup(ka, () -> {
-            destroy(ptr);
-        });
-    }
-
-    private void registerCleanupConstructed() {
-        registerCleanupSelf(this);
-    }
-
     public KfsAccess(String configFn) throws IOException {
         super(configFn);
-        registerCleanupConstructed();
     }
 
     public KfsAccess(String metaServerHost,
             int metaServerPort) throws IOException {
         super(metaServerHost, metaServerPort);
-        registerCleanupConstructed();
+    }
+
+    @Override
+    protected void finalize() throws Throwable {
+        try {
+            kfs_destroy();
+        } finally {
+            super.finalize();
+        }
     }
 }

src/java/qfs-access-pre-9/src/main/java/com/quantcast/qfs/access/KfsAccessBase.java

@@ -0,0 +1 @@
+../../../../../../../../qfs-access/src/main/java/com/quantcast/qfs/access/KfsAccessBase.java

src/java/qfs-access-pre-9/src/main/java/com/quantcast/qfs/access/KfsDelegation.java

@@ -0,0 +1 @@
+../../../../../../../../qfs-access/src/main/java/com/quantcast/qfs/access/KfsDelegation.java

src/java/qfs-access-pre-9/src/main/java/com/quantcast/qfs/access/KfsFileAttr.java

@@ -0,0 +1 @@
+../../../../../../../../qfs-access/src/main/java/com/quantcast/qfs/access/KfsFileAttr.java

src/java/qfs-access-9/src/main/java/com/quantcast/qfs/access/KfsInputChannel.java renamed to src/java/qfs-access-pre-9/src/main/java/com/quantcast/qfs/access/KfsInputChannel.java

@@ -1,11 +1,11 @@
 /**
  * $Id$
  *
- * Created 2025/04/20
+ * Created 2007/09/11
  *
- * @author: Mike Ovsiannikov (Quantcast Corporation)
+ * @author: Sriram Rao (Kosmix Corp.)
  *
- * Copyright 2025 Quantcast Corporation. All rights reserved.
+ * Copyright 2008-2012,2016 Quantcast Corporation. All rights reserved.
  * Copyright 2007 Kosmix Corp.
  *
  * This file is part of Kosmos File System (KFS).
@@ -22,30 +22,24 @@
  * implied. See the License for the specific language governing
  * permissions and limitations under the License.
  *
- * \brief Input channel java 9 style cleanup.
+ * \brief An input channel that does buffered I/O.  This is to reduce
+ * the overhead of JNI calls.
  */
 package com.quantcast.qfs.access;
 
-import java.lang.ref.Cleaner;
-
+/* A byte channel interface with seek support */
 final public class KfsInputChannel extends KfsInputChannelBase {
 
-    final private Cleaner.Cleanable cleanable;
-
     KfsInputChannel(KfsAccessBase ka, int fd) {
         super(ka, fd);
-        cleanable = registerCleanup();
-    }
-
-    private Cleaner.Cleanup registerCleanup() {
-        return KfsAccess.registerCleanup(this, state);
     }
 
-    final public synchronized void close() throws IOException {
+    @Override
+    protected void finalize() throws Throwable {
         try {
-            super.close();
+            state.release();
         } finally {
-            cleanable.clean();
+            super.finalize();
         }
     }
 }

src/java/qfs-access-pre-9/src/main/java/com/quantcast/qfs/access/KfsInputChannelBase.java

@@ -0,0 +1 @@
+../../../../../../../../qfs-access/src/main/java/com/quantcast/qfs/access/KfsInputChannelBase.java

src/java/qfs-access-9/src/main/java/com/quantcast/qfs/access/KfsOutputChannel.java renamed to src/java/qfs-access-pre-9/src/main/java/com/quantcast/qfs/access/KfsOutputChannel.java

@@ -1,11 +1,11 @@
 /**
  * $Id$
  *
- * Created 2025/04/20
+ * Created 2007/09/11
  *
- * @author: Mike Ovsiannikov (Quantcast Corporation)
+ * @author: Sriram Rao (Kosmix Corp.)
  *
- * Copyright 2025 Quantcast Corporation. All rights reserved.
+ * Copyright 2008-2012,2016 Quantcast Corporation. All rights reserved.
  * Copyright 2007 Kosmix Corp.
  *
  * This file is part of Kosmos File System (KFS).
@@ -22,30 +22,22 @@
  * implied. See the License for the specific language governing
  * permissions and limitations under the License.
  *
- * \brief Input channel java 9 style cleanup.
+ * \brief An output channel pre java 9 style cleanup.
  */
 package com.quantcast.qfs.access;
 
-import java.lang.ref.Cleaner;
+public class KfsOutputChannel extends KfsOutputChannelBase {
 
-final public class KfsOutputChannel extends KfsOutputChannelBase {
-
-    final private Cleaner.Cleanable cleanable;
-
-    KfsOutputChannel(KfsAccessBase ka, int fd) {
-        super(ka, fd);
-        cleanable = registerCleanup();
-    }
-
-    private Cleaner.Cleanable registerCleanup() {
-        return KfsAccess.registerCleanup(this, state);
+    KfsOutputChannel(KfsAccessBase kfsAccess, int fd, boolean append) {
+        super(kfsAccess, fd, append);
     }
 
-    public synchronized void close() throws IOException {
+    @Override
+    protected void finalize() throws Throwable {
         try {
-            super.close();
+            state.run();
         } finally {
-            cleanable.clean();
+            super.finalize();
         }
     }
 }

src/java/qfs-access-pre-9/src/main/java/com/quantcast/qfs/access/KfsOutputChannelBase.java

@@ -0,0 +1 @@
+../../../../../../../../qfs-access/src/main/java/com/quantcast/qfs/access/KfsOutputChannelBase.java

src/java/qfs-access-pre-9/src/main/java/com/quantcast/qfs/access/KfsTest.java

@@ -0,0 +1 @@
+../../../../../../../../qfs-access/src/main/java/com/quantcast/qfs/access/KfsTest.java

src/java/qfs-access-pre-9/src/main/java/com/quantcast/qfs/access/Positionable.java

@@ -0,0 +1 @@
+../../../../../../../../qfs-access/src/main/java/com/quantcast/qfs/access/Positionable.java

src/java/qfs-access-pre-9/src/test

@@ -0,0 +1 @@
+../../qfs-access/src/test

src/java/qfs-access/src/main/java/com/quantcast/qfs/access/KfsAccess.java

@@ -22,29 +22,44 @@
  * License for the specific language governing permissions and limitations under
  * the License.
  *
- * \brief Java wrappers to get to the KFS client.
+ * \brief QFS access java 9 style cleanup.
  */
 package com.quantcast.qfs.access;
 
 import java.io.IOException;
+import java.lang.ref.Cleaner;
 
 final public class KfsAccess extends KfsAccessBase {
 
+    private static Cleaner cleaner = Cleaner.create();
+
+    static Cleaner.Cleanable registerCleanup(Object obj, Runnable action) {
+        return cleaner.register(obj, action);
+    }
+
+    private static void registerCleanupSelf(KfsAccess ka) {
+        // Ensure that the native resource is cleaned up when this object is
+        // garbage collected.
+        // Make sure that this and ka are not referenced by the cleaner closure
+        // otherwise it will never be cleaned up.
+        final long ptr = ka.getCPtr();
+        registerCleanup(ka, () -> {
+            destroy(ptr);
+        });
+    }
+
+    private void registerCleanupConstructed() {
+        registerCleanupSelf(this);
+    }
+
     public KfsAccess(String configFn) throws IOException {
         super(configFn);
+        registerCleanupConstructed();
     }
 
     public KfsAccess(String metaServerHost,
-            int metaServerPort) throws IOException {
+                     int metaServerPort) throws IOException {
         super(metaServerHost, metaServerPort);
-    }
-
-    @Override
-    protected void finalize() throws Throwable {
-        try {
-            kfs_destroy();
-        } finally {
-            super.finalize();
-        }
+        registerCleanupConstructed();
     }
 }

src/java/qfs-access/src/main/java/com/quantcast/qfs/access/KfsInputChannel.java

@@ -1,11 +1,11 @@
 /**
  * $Id$
  *
- * Created 2007/09/11
+ * Created 2025/04/20
  *
- * @author: Sriram Rao (Kosmix Corp.)
+ * @author: Mike Ovsiannikov (Quantcast Corporation)
  *
- * Copyright 2008-2012,2016 Quantcast Corporation. All rights reserved.
+ * Copyright 2025 Quantcast Corporation. All rights reserved.
  * Copyright 2007 Kosmix Corp.
  *
  * This file is part of Kosmos File System (KFS).
@@ -22,24 +22,31 @@
  * implied. See the License for the specific language governing
  * permissions and limitations under the License.
  *
- * \brief An input channel that does buffered I/O.  This is to reduce
- * the overhead of JNI calls.
+ * \brief Input channel java 9 style cleanup.
  */
 package com.quantcast.qfs.access;
 
-/* A byte channel interface with seek support */
+import java.io.IOException;
+import java.lang.ref.Cleaner;
+
 final public class KfsInputChannel extends KfsInputChannelBase {
 
+    final private Cleaner.Cleanable cleanable;
+
     KfsInputChannel(KfsAccessBase ka, int fd) {
         super(ka, fd);
+        cleanable = registerCleanup();
+    }
+
+    private Cleaner.Cleanable registerCleanup() {
+        return KfsAccess.registerCleanup(this, state);
     }
 
-    @Override
-    protected void finalize() throws Throwable {
+    final public synchronized void close() throws IOException {
         try {
-            state.release();
+            super.close();
         } finally {
-            super.finalize();
+            cleanable.clean();
         }
     }
 }