| // *************************************************************************************************************************** |
| // * 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.juneau.internal; |
| |
| import java.util.*; |
| import java.util.concurrent.*; |
| import java.util.function.*; |
| |
| /** |
| * A hashmap that allows for two-part keys. |
| * |
| * <h5 class='section'>See Also:</h5><ul> |
| * </ul> |
| * |
| * @param <K1> Key part 1 type. |
| * @param <K2> Key part 2 type. |
| * @param <V> Value type. |
| * @serial exclude |
| */ |
| public class TwoKeyConcurrentCache<K1,K2,V> extends ConcurrentHashMap<TwoKeyConcurrentCache.Key<K1,K2>,V> { |
| private static final long serialVersionUID = 1L; |
| |
| private final boolean disabled; |
| private final BiFunction<K1,K2,V> supplier; |
| |
| /** |
| * Constructor. |
| */ |
| public TwoKeyConcurrentCache() { |
| this(false, null); |
| } |
| |
| /** |
| * Constructor. |
| * @param disabled If <jk>true</jk>, get/put operations are no-ops. |
| * @param supplier The supplier for this cache. |
| */ |
| public TwoKeyConcurrentCache(boolean disabled, BiFunction<K1,K2,V> supplier) { |
| this.disabled = disabled; |
| this.supplier = supplier; |
| } |
| |
| /** |
| * Adds an entry to this map. |
| * |
| * @param key1 Key part 1. Can be <jk>null</jk>. |
| * @param key2 Key part 2. Can be <jk>null</jk>. |
| * @param value Value. |
| * @return The previous value if there was one. |
| */ |
| public V put(K1 key1, K2 key2, V value) { |
| if (disabled) |
| return null; |
| Key<K1,K2> key = new Key<>(key1, key2); |
| return super.put(key, value); |
| } |
| |
| /** |
| * Retrieves an entry from this map. |
| * |
| * @param key1 Key part 1. Can be <jk>null</jk>. |
| * @param key2 Key part 2. Can be <jk>null</jk>. |
| * @return The previous value if there was one. |
| */ |
| public V get(K1 key1, K2 key2) { |
| if (disabled) |
| return (supplier == null ? null : supplier.apply(key1, key2)); |
| Key<K1,K2> key = new Key<>(key1, key2); |
| V v = super.get(key); |
| if (v == null && supplier != null) { |
| v = supplier.apply(key1, key2); |
| super.put(key, v); |
| } |
| return v; |
| } |
| |
| static class Key<K1,K2> { |
| final K1 k1; |
| final K2 k2; |
| final int hashCode; |
| |
| Key(K1 k1, K2 k2) { |
| this.k1 = k1; |
| this.k2 = k2; |
| this.hashCode = 31*(k1 == null ? 0 : k1.hashCode()) + (k2 == null ? 0 : k2.hashCode()); |
| } |
| |
| @Override /* Object */ |
| public int hashCode() { |
| return hashCode; |
| } |
| |
| @Override /* Object */ |
| @SuppressWarnings("unchecked") |
| public boolean equals(Object o) { |
| Key<K1,K2> ko = (Key<K1,K2>)o; |
| return Objects.equals(k1, ko.k1) && Objects.equals(k2, ko.k2); |
| } |
| } |
| } |