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.map;
  
  import org.jetbrains.annotations.NotNull;
  
  import java.util.AbstractSet;
  import java.util.Iterator;
  import java.util.Map;
  
  class ChronicleMapEntrySet<K, V> extends AbstractSet<Map.Entry<K, V>> {
  
      private final AbstractChronicleMap<K, V> map;
  
      public ChronicleMapEntrySet(AbstractChronicleMap<K, V> map) {
          this.map = map;
      }
  
      @NotNull
      public Iterator<Map.Entry<K, V>> iterator() {
          return new ChronicleMapIterator.OfEntries<>(map);
      }
  
      public final boolean contains(Object o) {
          if (!(o instanceof Map.Entry))
              return false;
          Map.Entry<?, ?> e = (Map.Entry<?, ?>) o;
          try {
              V v = map.get(e.getKey());
              return v != null && v.equals(e.getValue());
          } catch (ClassCastException | NullPointerException ex) {
              return false;
          }
      }
  
      public final boolean remove(Object o) {
          if (!(o instanceof Map.Entry))
              return false;
          Map.Entry<?, ?> e = (Map.Entry<?, ?>) o;
          try {
              Object key = e.getKey();
              Object value = e.getValue();
              return map.remove(key, value);
          } catch (ClassCastException | NullPointerException ex) {
              return false;
          }
      }
  
      public final int size() {
          return map.size();
      }
  
      public final boolean isEmpty() {
          return map.isEmpty();
      }
  
      public final void clear() {
          map.clear();
      }
  }
  