001// ***************************************************************************************************************************
002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
003// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
004// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
005// * with the License.  You may obtain a copy of the License at                                                              *
006// *                                                                                                                         *
007// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
008// *                                                                                                                         *
009// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an  *
010// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the        *
011// * specific language governing permissions and limitations under the License.                                              *
012// ***************************************************************************************************************************
013package org.apache.juneau.utils;
014
015import java.util.*;
016import java.util.concurrent.*;
017
018/**
019 * A hashmap that allows for two-part keys.
020 * @param <K1> Key part 1 type.
021 * @param <K2> Key part 2 type.
022 * @param <V> Value type.
023 */
024public class TwoKeyConcurrentHashMap<K1,K2,V> extends ConcurrentHashMap<TwoKeyConcurrentHashMap.Key<K1,K2>,V> {
025   private static final long serialVersionUID = 1L;
026
027   /**
028    * Adds an entry to this map.
029    *
030    * @param key1 Key part 1.  Can be <jk>null</jk>.
031    * @param key2 Key part 2.  Can be <jk>null</jk>.
032    * @param value Value.
033    * @return The previous value if there was one.
034    */
035   public V put(K1 key1, K2 key2, V value) {
036      Key<K1,K2> key = new Key<>(key1, key2);
037      return super.put(key, value);
038   }
039
040   /**
041    * Retrieves an entry from this map.
042    *
043    * @param key1 Key part 1.  Can be <jk>null</jk>.
044    * @param key2 Key part 2.  Can be <jk>null</jk>.
045    * @return The previous value if there was one.
046    */
047   public V get(K1 key1, K2 key2) {
048      Key<K1,K2> key = new Key<>(key1, key2);
049      return super.get(key);
050   }
051
052   static class Key<K1,K2> {
053      final K1 k1;
054      final K2 k2;
055      final int hashCode;
056
057      Key(K1 k1, K2 k2) {
058         this.k1 = k1;
059         this.k2 = k2;
060         this.hashCode = 31*(k1 == null ? 0 : k1.hashCode()) + (k2 == null ? 0 : k2.hashCode());
061      }
062
063      @Override /* Object */
064      public int hashCode() {
065         return hashCode;
066      }
067
068      @Override /* Object */
069      @SuppressWarnings("unchecked")
070      public boolean equals(Object o) {
071         Key<K1,K2> ko = (Key<K1,K2>)o;
072         return Objects.equals(k1, ko.k1) && Objects.equals(k2, ko.k2);
073      }
074   }
075}