code: /*
   * Copyright 2012-2018 Chronicle Map Contributors
   *
   * Licensed 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 net.openhft.chronicle.hash.impl;
  
  import net.openhft.chronicle.core.OS;
  import net.openhft.chronicle.hash.impl.util.CanonicalRandomAccessFiles;
  
  import java.io.File;
  import java.io.IOException;
  
  public final class PersistedChronicleHashResources extends ChronicleHashResources {
  
      private File file;
  
      public PersistedChronicleHashResources(File file) {
          this.file = file;
          OS.memory().storeFence(); // Emulate final semantics of the file field
      }
  
      @Override
      void releaseMemoryResource(MemoryResource mapping) throws IOException {
          OS.unmap(mapping.address, mapping.size);
      }
  
      @Override
      Throwable releaseExtraSystemResources() {
          if (file == null)
              return null;
          Throwable thrown = null;
          try {
              CanonicalRandomAccessFiles.release(file);
              file = null;
          } catch (Throwable t) {
              thrown = t;
          }
          return thrown;
      }
  }
  