#5173

Committed 29 Dec 2025 05:27AM UTC coverage: 0.0% (-100.0%) from 100.0%

Build # #5173

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ben-manes

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speed up development ci build

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/caffeine/src/main/java/com/github/benmanes/caffeine/cache/AsyncCacheLoader.java

/*
 * Copyright 2016 Ben Manes. All Rights Reserved.
 *
 * 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 com.github.benmanes.caffeine.cache;

import static java.util.Objects.requireNonNull;

import java.util.Map;
import java.util.Set;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.Executor;
import java.util.function.BiFunction;
import java.util.function.Function;

import org.jspecify.annotations.NonNull;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Computes or retrieves values asynchronously based on a key, for use in populating a
 * {@link AsyncLoadingCache}.
 * <p>
 * Most implementations will only need to implement {@link #asyncLoad}. Other methods may be
 * overridden as desired.
 * <p>
 * Usage example:
 * {@snippet class=com.github.benmanes.caffeine.cache.Snippets region=asyncLoader_basic lang=java}
 *
 * @param <K> the type of keys
 * @param <V> the type of values. A loader may return null values if and only if it declares a
 *     nullable value type. A cache may return null values if and only if its loader does. (Null
 *     values are still never <i>stored</i> in the cache.)
 * @author ben.manes@gmail.com (Ben Manes)
 */
@NullMarked
@FunctionalInterface
@SuppressWarnings({"JavadocDeclaration", "JavadocReference", "PMD.SignatureDeclareThrowsException"})
public interface AsyncCacheLoader<K, V extends @Nullable Object> {

  /**
   * Asynchronously computes or retrieves the value corresponding to {@code key}.
   * <p>
   * <b>Warning:</b> loading <b>must not</b> attempt to update any mappings of this cache directly.
   *
   * @param key the non-null key whose value should be loaded
   * @param executor the executor with which the entry may be asynchronously loaded
   * @return the future value associated with {@code key}
   * @throws Exception or Error, in which case the mapping is unchanged
   * @throws InterruptedException if this method is interrupted. {@code InterruptedException} is
   *         treated like any other {@code Exception} in all respects except that, when it is
   *         caught, the thread's interrupt status is set
   */
  CompletableFuture<? extends V> asyncLoad(K key, Executor executor) throws Exception;

  /**
   * Asynchronously computes or retrieves the values corresponding to {@code keys}. This method is
   * called by {@link AsyncLoadingCache#getAll}.
   * <p>
   * If the returned map doesn't contain all requested {@code keys}, then the entries it does
   * contain will be cached, and {@code getAll} will return the partial results. If the returned map
   * contains extra keys not present in {@code keys}, then all returned entries will be cached, but
   * only the entries for {@code keys} will be returned from {@code getAll}.
   * <p>
   * This method should be overridden when bulk retrieval is significantly more efficient than many
   * individual lookups. Note that {@link AsyncLoadingCache#getAll} will defer to individual calls
   * to {@link AsyncLoadingCache#get} if this method is not overridden.
   * <p>
   * <b>Warning:</b> loading <b>must not</b> attempt to update any mappings of this cache directly.
   *
   * @param keys the unique, non-null keys whose values should be loaded
   * @param executor the executor with which the entry may be asynchronously loaded
   * @return a future containing the map from each key in {@code keys} to the value associated with
   *         that key; <b>may not contain null values</b>
   * @throws Exception or Error, in which case the mappings are unchanged
   * @throws InterruptedException if this method is interrupted. {@code InterruptedException} is
   *         treated like any other {@code Exception} in all respects except that, when it is
   *         caught, the thread's interrupt status is set
   */
  default CompletableFuture<? extends Map<? extends K, ? extends @NonNull V>> asyncLoadAll(
      Set<? extends K> keys, Executor executor) throws Exception {
    throw new UnsupportedOperationException();
  }

  /**
   * Asynchronously computes or retrieves a replacement value corresponding to an already-cached
   * {@code key}. If the replacement value is not found, then the mapping will be removed if
   * {@code null} is computed. This method is called when an existing cache entry is refreshed by
   * {@link Caffeine#refreshAfterWrite}, or through a call to {@link LoadingCache#refresh}.
   * <p>
   * <b>Warning:</b> loading <b>must not</b> attempt to update any mappings of this cache directly
   * or block waiting for other cache operations to complete.
   * <p>
   * <b>Note:</b> <i>all exceptions thrown by this method will be logged and then swallowed</i>.
   *
   * @param key the non-null key whose value should be loaded
   * @param oldValue the non-null old value corresponding to {@code key}
   * @param executor the executor with which the entry may be asynchronously loaded
   * @return a future containing the new value associated with {@code key}, or containing
   *         {@code null} if the mapping is to be removed
   * @throws Exception or Error, in which case the mapping is unchanged
   * @throws InterruptedException if this method is interrupted. {@code InterruptedException} is
   *         treated like any other {@code Exception} in all respects except that, when it is
   *         caught, the thread's interrupt status is set
   */
  default CompletableFuture<? extends V> asyncReload(
      K key, @NonNull V oldValue, Executor executor) throws Exception {
    return asyncLoad(key, executor);
  }

  /**
   * Returns an asynchronous cache loader that delegates to the supplied mapping function for
   * retrieving the values. Note that {@link #asyncLoad} will discard any additional mappings
   * loaded when retrieving the {@code key} prior to returning the value to the cache.
   * <p>
   * Usage example:
   * {@snippet class=com.github.benmanes.caffeine.cache.Snippets
   *           region=asyncLoader_bulk_sync lang=java}
   *
   * @param <K> the key type
   * @param <V> the value type
   * @param mappingFunction the function to asynchronously compute the values
   * @return an asynchronous cache loader that delegates to the supplied {@code mappingFunction}
   * @throws NullPointerException if the mappingFunction is null
   */
  static <K, V extends @Nullable Object> AsyncCacheLoader<K, V> bulk(
      Function<? super Set<? extends K>, ? extends Map<? extends K, ? extends @NonNull V>>
          mappingFunction) {
    return CacheLoader.bulk(mappingFunction);
  }

  /**
   * Returns an asynchronous cache loader that delegates to the supplied mapping function for
   * retrieving the values. Note that {@link #asyncLoad} will silently discard any additional
   * mappings loaded when retrieving the {@code key} prior to returning the value to the cache.
   * <p>
   * Usage example:
   * {@snippet class=com.github.benmanes.caffeine.cache.Snippets
   *           region=asyncLoader_bulk_async lang=java}
   *
   * @param <K> the key type
   * @param <V> the value type
   * @param mappingFunction the function to asynchronously compute the values
   * @return an asynchronous cache loader that delegates to the supplied {@code mappingFunction}
   * @throws NullPointerException if the mappingFunction is null
   */
  static <K, V extends @Nullable Object> AsyncCacheLoader<K, V> bulk(
      BiFunction<
          ? super Set<? extends K>,
          ? super Executor,
          ? extends CompletableFuture<? extends Map<? extends K, ? extends @NonNull V>>>
      mappingFunction) {
    requireNonNull(mappingFunction);
    return new AsyncCacheLoader<>() {
      @Override public CompletableFuture<V> asyncLoad(K key, Executor executor) {
        return asyncLoadAll(Set.of(key), executor)
            .thenApply(results -> results.get(key));
      }
      @Override public CompletableFuture<Map<K, V>> asyncLoadAll(
          Set<? extends K> keys, Executor executor) {
        requireNonNull(keys);
        requireNonNull(executor);
        @SuppressWarnings("unchecked")
        var future = (CompletableFuture<Map<K, V>>) mappingFunction.apply(keys, executor);
        return future;
      }
    };
  }
}

1	/*
2	* Copyright 2016 Ben Manes. All Rights Reserved.
3	*
4	* Licensed under the Apache License, Version 2.0 (the "License");
5	* you may not use this file except in compliance with the License.
6	* You may obtain a copy of the License at
7	*
8	* http://www.apache.org/licenses/LICENSE-2.0
9	*
10	* Unless required by applicable law or agreed to in writing, software
11	* distributed under the License is distributed on an "AS IS" BASIS,
12	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13	* See the License for the specific language governing permissions and
14	* limitations under the License.
15	*/
16	package com.github.benmanes.caffeine.cache;
17
18	import static java.util.Objects.requireNonNull;
19
20	import java.util.Map;
21	import java.util.Set;
22	import java.util.concurrent.CompletableFuture;
23	import java.util.concurrent.Executor;
24	import java.util.function.BiFunction;
25	import java.util.function.Function;
26
27	import org.jspecify.annotations.NonNull;
28	import org.jspecify.annotations.NullMarked;
29	import org.jspecify.annotations.Nullable;
30
31	/**
32	* Computes or retrieves values asynchronously based on a key, for use in populating a
33	* {@link AsyncLoadingCache}.
34	* <p>
35	* Most implementations will only need to implement {@link #asyncLoad}. Other methods may be
36	* overridden as desired.
37	* <p>
38	* Usage example:
39	* {@snippet class=com.github.benmanes.caffeine.cache.Snippets region=asyncLoader_basic lang=java}
40	*
41	* @param <K> the type of keys
42	* @param <V> the type of values. A loader may return null values if and only if it declares a
43	* nullable value type. A cache may return null values if and only if its loader does. (Null
44	* values are still never <i>stored</i> in the cache.)
45	* @author ben.manes@gmail.com (Ben Manes)
46	*/
47	@NullMarked
48	@FunctionalInterface
49	@SuppressWarnings({"JavadocDeclaration", "JavadocReference", "PMD.SignatureDeclareThrowsException"})
50	public interface AsyncCacheLoader<K, V extends @Nullable Object> {
51
52	/**
53	* Asynchronously computes or retrieves the value corresponding to {@code key}.
54	* <p>
55	* <b>Warning:</b> loading <b>must not</b> attempt to update any mappings of this cache directly.
56	*
57	* @param key the non-null key whose value should be loaded
58	* @param executor the executor with which the entry may be asynchronously loaded
59	* @return the future value associated with {@code key}
60	* @throws Exception or Error, in which case the mapping is unchanged
61	* @throws InterruptedException if this method is interrupted. {@code InterruptedException} is
62	* treated like any other {@code Exception} in all respects except that, when it is
63	* caught, the thread's interrupt status is set
64	*/
65	CompletableFuture<? extends V> asyncLoad(K key, Executor executor) throws Exception;
66
67	/**
68	* Asynchronously computes or retrieves the values corresponding to {@code keys}. This method is
69	* called by {@link AsyncLoadingCache#getAll}.
70	* <p>
71	* If the returned map doesn't contain all requested {@code keys}, then the entries it does
72	* contain will be cached, and {@code getAll} will return the partial results. If the returned map
73	* contains extra keys not present in {@code keys}, then all returned entries will be cached, but
74	* only the entries for {@code keys} will be returned from {@code getAll}.
75	* <p>
76	* This method should be overridden when bulk retrieval is significantly more efficient than many
77	* individual lookups. Note that {@link AsyncLoadingCache#getAll} will defer to individual calls
78	* to {@link AsyncLoadingCache#get} if this method is not overridden.
79	* <p>
80	* <b>Warning:</b> loading <b>must not</b> attempt to update any mappings of this cache directly.
81	*
82	* @param keys the unique, non-null keys whose values should be loaded
83	* @param executor the executor with which the entry may be asynchronously loaded
84	* @return a future containing the map from each key in {@code keys} to the value associated with
85	* that key; <b>may not contain null values</b>
86	* @throws Exception or Error, in which case the mappings are unchanged
87	* @throws InterruptedException if this method is interrupted. {@code InterruptedException} is
88	* treated like any other {@code Exception} in all respects except that, when it is
89	* caught, the thread's interrupt status is set
90	*/
91	default CompletableFuture<? extends Map<? extends K, ? extends @NonNull V>> asyncLoadAll(
92	Set<? extends K> keys, Executor executor) throws Exception {
93	throw new UnsupportedOperationException();	×
94	}
95
96	/**
97	* Asynchronously computes or retrieves a replacement value corresponding to an already-cached
98	* {@code key}. If the replacement value is not found, then the mapping will be removed if
99	* {@code null} is computed. This method is called when an existing cache entry is refreshed by
100	* {@link Caffeine#refreshAfterWrite}, or through a call to {@link LoadingCache#refresh}.
101	* <p>
102	* <b>Warning:</b> loading <b>must not</b> attempt to update any mappings of this cache directly
103	* or block waiting for other cache operations to complete.
104	* <p>
105	* <b>Note:</b> <i>all exceptions thrown by this method will be logged and then swallowed</i>.
106	*
107	* @param key the non-null key whose value should be loaded
108	* @param oldValue the non-null old value corresponding to {@code key}
109	* @param executor the executor with which the entry may be asynchronously loaded
110	* @return a future containing the new value associated with {@code key}, or containing
111	* {@code null} if the mapping is to be removed
112	* @throws Exception or Error, in which case the mapping is unchanged
113	* @throws InterruptedException if this method is interrupted. {@code InterruptedException} is
114	* treated like any other {@code Exception} in all respects except that, when it is
115	* caught, the thread's interrupt status is set
116	*/
117	default CompletableFuture<? extends V> asyncReload(
118	K key, @NonNull V oldValue, Executor executor) throws Exception {
119	return asyncLoad(key, executor);	×
120	}
121
122	/**
123	* Returns an asynchronous cache loader that delegates to the supplied mapping function for
124	* retrieving the values. Note that {@link #asyncLoad} will discard any additional mappings
125	* loaded when retrieving the {@code key} prior to returning the value to the cache.
126	* <p>
127	* Usage example:
128	* {@snippet class=com.github.benmanes.caffeine.cache.Snippets
129	* region=asyncLoader_bulk_sync lang=java}
130	*
131	* @param <K> the key type
132	* @param <V> the value type
133	* @param mappingFunction the function to asynchronously compute the values
134	* @return an asynchronous cache loader that delegates to the supplied {@code mappingFunction}
135	* @throws NullPointerException if the mappingFunction is null
136	*/
137	static <K, V extends @Nullable Object> AsyncCacheLoader<K, V> bulk(
138	Function<? super Set<? extends K>, ? extends Map<? extends K, ? extends @NonNull V>>
139	mappingFunction) {
140	return CacheLoader.bulk(mappingFunction);	×
141	}
142
143	/**
144	* Returns an asynchronous cache loader that delegates to the supplied mapping function for
145	* retrieving the values. Note that {@link #asyncLoad} will silently discard any additional
146	* mappings loaded when retrieving the {@code key} prior to returning the value to the cache.
147	* <p>
148	* Usage example:
149	* {@snippet class=com.github.benmanes.caffeine.cache.Snippets
150	* region=asyncLoader_bulk_async lang=java}
151	*
152	* @param <K> the key type
153	* @param <V> the value type
154	* @param mappingFunction the function to asynchronously compute the values
155	* @return an asynchronous cache loader that delegates to the supplied {@code mappingFunction}
156	* @throws NullPointerException if the mappingFunction is null
157	*/
158	static <K, V extends @Nullable Object> AsyncCacheLoader<K, V> bulk(
159	BiFunction<
160	? super Set<? extends K>,
161	? super Executor,
162	? extends CompletableFuture<? extends Map<? extends K, ? extends @NonNull V>>>
163	mappingFunction) {
164	requireNonNull(mappingFunction);	×
165	return new AsyncCacheLoader<>() {	×
166	@Override public CompletableFuture<V> asyncLoad(K key, Executor executor) {
167	return asyncLoadAll(Set.of(key), executor)	×
168	.thenApply(results -> results.get(key));	×
169	}
170	@Override public CompletableFuture<Map<K, V>> asyncLoadAll(
171	Set<? extends K> keys, Executor executor) {
172	requireNonNull(keys);	×
173	requireNonNull(executor);	×
174	@SuppressWarnings("unchecked")
175	var future = (CompletableFuture<Map<K, V>>) mappingFunction.apply(keys, executor);	×
176	return future;	×
177	}
178	};
179	}
180	}

ben-manes / caffeine / #5173

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