Add platform compatible implementations for Java11+

datasketches-memory-java11/pom.xml

@@ -39,4 +39,22 @@
         <maven.compiler.target>${java.version}</maven.compiler.target>
     </properties>
 
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-compiler-plugin</artifactId>
+                    <version>${maven-compiler-plugin.version}</version>
+                    <configuration>
+                        <compilerArgs>
+                            <arg>--add-exports</arg>
+                            <arg>java.base/jdk.internal.ref=org.apache.datasketches.memory</arg>
+                        </compilerArgs>
+                    </configuration>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+
 </project>

datasketches-memory-java11/src/main/java/module-info.java

@@ -0,0 +1,26 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+@SuppressWarnings("javadoc")
+module org.apache.datasketches.memory {
+  requires java.base;
+  requires java.logging;
+  requires jdk.unsupported;
+
+  exports org.apache.datasketches.memory;
+}

datasketches-memory-java11/src/main/java/org/apache/datasketches/memory/Map.java

@@ -0,0 +1,46 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.datasketches.memory;
+
+/**
+ * Read only interface for a memory mapped file
+ *
+ * @author Roman Leventov
+ * @author Lee Rhodes
+ * @author Praveenkumar Venkatesan
+ */
+public interface Map extends AutoCloseable {
+
+  /**
+   * @see <a href="https://docs.oracle.com/javase/8/docs/api/java/nio/MappedByteBuffer.html#load--">
+   * java/nio/MappedByteBuffer.load</a>
+   */
+  void load();
+
+  /**
+   * @return true if loaded
+   *
+   * @see <a href=
+   * "https://docs.oracle.com/javase/8/docs/api/java/nio/MappedByteBuffer.html#isLoaded--"> java
+   * /nio/MappedByteBuffer.isLoaded</a>
+   */
+  boolean isLoaded();
+
+}

datasketches-memory-java11/src/main/java/org/apache/datasketches/memory/internal/MemoryCleaner.java

@@ -0,0 +1,50 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.datasketches.memory.internal;
+
+import jdk.internal.ref.Cleaner;
+
+/**
+ * Extracts a version-dependent reference to the `jdk.internal.ref.Cleaner` into
+ * a standalone class. The package name for Cleaner has changed in
+ * later versions. The appropriate class will be loaded by the class loader
+ * depending on the Java version that is used.
+ * For more information, see: https://openjdk.java.net/jeps/238
+ */
+public class MemoryCleaner {
+  private final Cleaner cleaner;
+
+  /**
+   * Creates a new `jdk.internal.ref.Cleaner`.
+   * @param referent the object to be cleaned
+   * @param deallocator - the cleanup code to be run when the cleaner is invoked.
+   * return MemoryCleaner
+   */
+  public MemoryCleaner(final Object referent, final Runnable deallocator) {
+    cleaner = Cleaner.create(referent, deallocator);
+  }
+
+  /**
+   * Runs this cleaner, if it has not been run before.
+   */
+  public void clean() {
+    cleaner.clean();
+  }
+}

datasketches-memory-java11/src/main/java/org/apache/datasketches/memory/internal/VirtualMachineMemory.java

@@ -0,0 +1,74 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.datasketches.memory.internal;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+/**
+ * Extracts a version-dependent reference to the `jdk.internal.misc.VM` into
+ * a standalone class. The package name for VM has changed in
+ * later versions. The appropriate class will be loaded by the class loader
+ * depending on the Java version that is used.
+ * For more information, see: https://openjdk.java.net/jeps/238
+ */
+public final class VirtualMachineMemory {
+
+  private static final Class<?> VM_CLASS;
+  private static final Method VM_MAX_DIRECT_MEMORY_METHOD;
+  private static final Method VM_IS_DIRECT_MEMORY_PAGE_ALIGNED_METHOD;
+  private static final long maxDBBMemory;
+  private static final boolean isPageAligned;
+
+  static {
+    try {
+      VM_CLASS = Class.forName("jdk.internal.misc.VM");
+      VM_MAX_DIRECT_MEMORY_METHOD = VM_CLASS.getDeclaredMethod("maxDirectMemory");
+      VM_MAX_DIRECT_MEMORY_METHOD.setAccessible(true);
+      maxDBBMemory = (long) VM_MAX_DIRECT_MEMORY_METHOD.invoke(null); //static method
+
+      VM_IS_DIRECT_MEMORY_PAGE_ALIGNED_METHOD =
+          VM_CLASS.getDeclaredMethod("isDirectMemoryPageAligned");
+      VM_IS_DIRECT_MEMORY_PAGE_ALIGNED_METHOD.setAccessible(true);
+      isPageAligned = (boolean) VM_IS_DIRECT_MEMORY_PAGE_ALIGNED_METHOD
+          .invoke(null); //static method
+    } catch (final ClassNotFoundException | NoSuchMethodException |  IllegalAccessException
+        | IllegalArgumentException | InvocationTargetException | SecurityException e) {
+      throw new RuntimeException("Could not acquire jdk.internal.misc.VM: " + e.getClass());
+    }
+  }
+
+  /**
+   * Returns the maximum amount of allocatable direct buffer memory.
+   * The directMemory variable is initialized during system initialization.
+   * @return the maximum amount of allocatable direct buffer memory.
+   */
+  public static long getMaxDBBMemory() {
+    return maxDBBMemory;
+  }
+
+  /**
+   * Returns true if the direct buffers should be page aligned.
+   * @return flag that determines whether direct buffers should be page aligned.
+   */
+  public static boolean getIsPageAligned() {
+    return isPageAligned;
+  }
+}