content: /*
   * Copyright 2010 Proofpoint, Inc.
   *
   * 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 io.airlift.discovery.store;
  
  import com.google.common.base.Preconditions;
  import com.google.inject.Inject;
  
  import java.nio.ByteBuffer;
  import java.util.EnumSet;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.ConcurrentMap;
  
  import static io.airlift.discovery.store.Version.Occurs.AFTER;
  import static io.airlift.discovery.store.Version.Occurs.SAME;
  
  public class InMemoryStore
          implements LocalStore
  {
      private final ConcurrentMap<ByteBuffer, Entry> map = new ConcurrentHashMap<ByteBuffer, Entry>();
      private final ConflictResolver resolver;
  
      @Inject
      public InMemoryStore(ConflictResolver resolver)
      {
          this.resolver = resolver;
      }
  
      @Override
      public void put(Entry entry)
      {
          ByteBuffer key = ByteBuffer.wrap(entry.getKey());
  
          boolean done = false;
          while (!done) {
              Entry old = map.putIfAbsent(key, entry);
  
              done = true;
              if (old != null) {
                  entry = resolver.resolve(old, entry);
  
                  if (entry != old) {
                      done = map.replace(key, old, entry);
                  }
              }
          }
      }
  
      @Override
      public Entry get(byte[] key)
      {
          Preconditions.checkNotNull(key, "key is null");
  
          return map.get(ByteBuffer.wrap(key));
      }
  
      @Override
      public void delete(byte[] key, Version version)
      {
          Preconditions.checkNotNull(key, "key is null");
  
          ByteBuffer wrappedKey = ByteBuffer.wrap(key);
  
          boolean done = false;
          while (!done) {
              Entry old = map.get(wrappedKey);
  
              done = true;
              if (old != null && EnumSet.of(AFTER, SAME).contains(version.compare(old.getVersion()))) {
                  done = map.remove(wrappedKey, old);
              }
          }
      }
  
      @Override
      public Iterable<Entry> getAll()
      {
          return map.values();
      }
  }
  