minor touchups

.github/actions/run-gradle/action.yml

@@ -8,7 +8,7 @@ inputs:
     required: true
     description: The JDK version
   early-access:
-    default: '23'
+    default: '24'
     required: false
     description: The early access release
   graal:
@@ -79,7 +79,7 @@ runs:
         distribution: temurin
     - name: Setup Gradle
       id: setup-gradle
-      uses: gradle/actions/setup-gradle@d9336dac04dea2507a617466bc058a3def92b18b # v3.4.0
+      uses: gradle/actions/setup-gradle@31ae3562f68c96d481c31bc1a8a55cc1be162f83 # v3.4.1
       env:
         JAVA_HOME: ${{ steps.setup-gradle-jdk.outputs.path }}
         ORG_GRADLE_PROJECT_org.gradle.java.installations.auto-download: 'false'

.github/workflows/actionlint.yml

@@ -16,7 +16,7 @@ jobs:
             github.com:443
       - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
       - name: actionlint
-        uses: reviewdog/action-actionlint@fd627997c9688c2f39e13917aed23873c031b834 # v1.48.0
+        uses: reviewdog/action-actionlint@52819f5f70db72e17c2fadecd44a791ae4459276 # v1.49.0
         env:
           SHELLCHECK_OPTS: -e SC2001 -e SC2035 -e SC2046 -e SC2061 -e SC2086 -e SC2156
         with:

.github/workflows/benchmarks.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ 11, 21, 23, GraalVM ]
+        java: [ 11, 21, 24, GraalVM ]
     env:
       JAVA_VERSION: ${{ matrix.java }}
     steps:

.github/workflows/build.yml

@@ -39,7 +39,7 @@ env:
     schemastore.org:443
     www.graalvm.org:443
   PUBLISH_JDK: 11
-  EA_JDK: 23
+  EA_JDK: 24
 
 jobs:
   compile:
@@ -48,7 +48,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ 11, 22, 23, GraalVM ]
+        java: [ 11, 22, 24, GraalVM ]
     env:
       JAVA_VERSION: ${{ matrix.java }}
     steps:

.github/workflows/dependency-submission-pr-retreive.yml

@@ -35,6 +35,6 @@ jobs:
             repo1.maven.org:443
             services.gradle.org:443
       - name: Retrieve and submit dependency graph
-        uses: gradle/actions/dependency-submission@d9336dac04dea2507a617466bc058a3def92b18b # v3.4.0
+        uses: gradle/actions/dependency-submission@31ae3562f68c96d481c31bc1a8a55cc1be162f83 # v3.4.1
         with:
           dependency-graph: download-and-submit

.github/workflows/dependency-submission-pr-submit.yml

@@ -38,7 +38,7 @@ jobs:
           java-version: ${{ env.JAVA_VERSION }}
           distribution: temurin
       - name: Submit Dependency Graph
-        uses: gradle/actions/dependency-submission@d9336dac04dea2507a617466bc058a3def92b18b # v3.4.0
+        uses: gradle/actions/dependency-submission@31ae3562f68c96d481c31bc1a8a55cc1be162f83 # v3.4.1
         with:
           cache-encryption-key: ${{ secrets.GRADLE_ENCRYPTION_KEY }}
           dependency-graph: generate-and-upload

.github/workflows/dependency-submission.yml

@@ -38,6 +38,6 @@ jobs:
           java-version: ${{ env.JAVA_VERSION }}
           distribution: temurin
       - name: Submit Dependency Graph
-        uses: gradle/actions/dependency-submission@d9336dac04dea2507a617466bc058a3def92b18b # v3.4.0
+        uses: gradle/actions/dependency-submission@31ae3562f68c96d481c31bc1a8a55cc1be162f83 # v3.4.1
         with:
           cache-encryption-key: ${{ secrets.GRADLE_ENCRYPTION_KEY }}

.github/workflows/examples.yml

@@ -39,7 +39,7 @@ jobs:
           java-version: ${{ env.JAVA_VERSION }}
           distribution: temurin
       - name: Setup Gradle
-        uses: gradle/actions/setup-gradle@d9336dac04dea2507a617466bc058a3def92b18b # v3.4.0
+        uses: gradle/actions/setup-gradle@31ae3562f68c96d481c31bc1a8a55cc1be162f83 # v3.4.1
         with:
           add-job-summary: never
           cache-read-only: false

.github/workflows/gradle-wrapper-validation.yml

@@ -18,4 +18,4 @@ jobs:
             github.com:443
             services.gradle.org:443
       - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
-      - uses: gradle/actions/wrapper-validation@d9336dac04dea2507a617466bc058a3def92b18b # v3.4.0
+      - uses: gradle/actions/wrapper-validation@31ae3562f68c96d481c31bc1a8a55cc1be162f83 # v3.4.1

examples/indexable/README.md

@@ -18,7 +18,7 @@ CREATE TABLE user_info (
   username      varchar(255) NOT NULL,
   password_hash varchar(255) NOT NULL,
   created_on    timestamp with time zone DEFAULT CURRENT_TIMESTAMP,
-  modified_on   timestamp with time zone DEFAULT CURRENT_TIMESTAMP,
+  modified_on   timestamp with time zone DEFAULT CURRENT_TIMESTAMP
 );
 CREATE UNIQUE INDEX user_info_email_idx ON user_info (email);
 CREATE UNIQUE INDEX user_info_username_idx ON user_info (username);
@@ -50,8 +50,8 @@ constraints. The value can then be queried using the typed key.
 ```java
 var cache = new IndexedCache.Builder<UserKey, User>()
     .primaryKey(user -> new UserById(user.id()))
-    .addSecondaryKey(user -> new UserByLogin(user.login()))
     .addSecondaryKey(user -> new UserByEmail(user.email()))
+    .addSecondaryKey(user -> new UserByLogin(user.username()))
     .expireAfterWrite(Duration.ofMinutes(5))
     .maximumSize(10_000)
     .build(this::findUser);
@@ -63,7 +63,7 @@ assertThat(userByEmail).isSameInstanceAs(userByLogin);
 
 ### How it works
 The sample [IndexedCache][] combines a key-value cache with an associated mapping from the
-individual keys to the entry's complete set. Consistency is maintained by acquiring the write lock
+individual keys to the entry's complete set. Consistency is maintained by acquiring the entry's lock
 through the cache using the primary key before updating the index. This prevents race conditions
 when the entry is concurrently updated and evicted, which could otherwise lead to missing or
 non-resident key associations in the index. On eviction, a listener discards the keys while holding

examples/indexable/src/main/java/com/github/benmanes/caffeine/examples/indexable/IndexedCache.java

@@ -15,11 +15,13 @@
  */
 package com.github.benmanes.caffeine.examples.indexable;
 
-import static com.google.common.collect.ImmutableSet.toImmutableSet;
+import static com.google.common.base.Preconditions.checkState;
 import static java.util.Objects.requireNonNull;
 
 import java.time.Duration;
-import java.util.Set;
+import java.util.Collections;
+import java.util.LinkedHashSet;
+import java.util.SequencedSet;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.locks.Lock;
@@ -28,7 +30,6 @@
 import com.github.benmanes.caffeine.cache.Cache;
 import com.github.benmanes.caffeine.cache.Caffeine;
 import com.github.benmanes.caffeine.cache.Ticker;
-import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Sets;
 import com.google.common.util.concurrent.Striped;
 
@@ -42,29 +43,27 @@
  * @author ben.manes@gmail.com (Ben Manes)
  */
 public final class IndexedCache<K, V> {
-  final ConcurrentMap<K, Index<K>> indexes;
+  final ConcurrentMap<K, SequencedSet<K>> indexes;
+  final SequencedSet<Function<V, K>> indexers;
   final Function<K, V> mappingFunction;
-  final Function<V, Index<K>> indexer;
   final Striped<Lock> locks;
   final Cache<K, V> store;
 
-  private IndexedCache(Caffeine<Object, Object> cacheBuilder, Function<K, V> mappingFunction,
-      Function<V, K> primary, Set<Function<V, K>> secondaries) {
-    this.locks = Striped.lock(1_000);
-    this.mappingFunction = mappingFunction;
+  private IndexedCache(Caffeine<Object, Object> cacheBuilder,
+      Function<K, V> mappingFunction, SequencedSet<Function<V, K>> indexers) {
     this.indexes = new ConcurrentHashMap<>();
+    this.mappingFunction = mappingFunction;
+    this.locks = Striped.lock(1_024);
+    this.indexers = indexers;
     this.store = cacheBuilder
-        .evictionListener((key, value, cause) ->
-            indexes.keySet().removeAll(indexes.get(key).allKeys()))
+        .evictionListener((key, value, cause) -> indexes.keySet().removeAll(indexes.get(key)))
         .build();
-    this.indexer = value -> new Index<>(primary.apply(value),
-        secondaries.stream().map(indexer -> indexer.apply(value)).collect(toImmutableSet()));
   }
 
   /** Returns the value associated with the key or {@code null} if not found. */
   public V getIfPresent(K key) {
     var index = indexes.get(key);
-    return (index == null) ? null : store.getIfPresent(index.primaryKey());
+    return (index == null) ? null : store.getIfPresent(index.getFirst());
   }
 
   /**
@@ -103,13 +102,12 @@ public V get(K key) {
   /** Associates the {@code value} with its keys, replacing the old value and keys if present. */
   public V put(V value) {
     requireNonNull(value);
-    var index = indexer.apply(value);
-    return store.asMap().compute(index.primaryKey(), (key, oldValue) -> {
+    var index = buildIndex(value);
+    return store.asMap().compute(index.getFirst(), (key, oldValue) -> {
       if (oldValue != null) {
-        indexes.keySet().removeAll(Sets.difference(
-            indexes.get(index.primaryKey()).allKeys(), index.allKeys()));
+        indexes.keySet().removeAll(Sets.difference(indexes.get(index.getFirst()), index));
       }
-      for (var indexKey : index.allKeys()) {
+      for (var indexKey : index) {
         indexes.put(indexKey, index);
       }
       return value;
@@ -123,28 +121,36 @@ public void invalidate(K key) {
       return;
     }
 
-    store.asMap().computeIfPresent(index.primaryKey(), (k, v) -> {
-      indexes.keySet().removeAll(index.allKeys());
+    store.asMap().computeIfPresent(index.getFirst(), (k, v) -> {
+      indexes.keySet().removeAll(indexes.get(key));
       return null;
     });
   }
 
-  private record Index<K>(K primaryKey, Set<K> secondaryKeys) {
-    public Set<K> allKeys() {
-      return Sets.union(Set.of(primaryKey), secondaryKeys);
+  /** Returns a sequence of keys where the first item is the primary key. */
+  private SequencedSet<K> buildIndex(V value) {
+    var index = LinkedHashSet.<K>newLinkedHashSet(indexers.size());
+    for (var indexer : indexers) {
+      var key = indexer.apply(value);
+      if (key == null) {
+        checkState(!index.isEmpty(), "The primary key may not be null");
+      } else {
+        index.add(key);
+      }
     }
+    return Collections.unmodifiableSequencedSet(index);
   }
 
   /** This builder could be extended to support most cache options, but not weak keys. */
   public static final class Builder<K, V> {
+    final SequencedSet<Function<V, K>> indexers;
     final Caffeine<Object, Object> cacheBuilder;
-    final ImmutableSet.Builder<Function<V, K>> secondaries;
 
-    Function<V, K> primary;
+    boolean hasPrimary;
 
     public Builder() {
+      indexers = new LinkedHashSet<>();
       cacheBuilder = Caffeine.newBuilder();
-      secondaries = ImmutableSet.builder();
     }
 
     /** See {@link Caffeine#expireAfterWrite(Duration)}. */
@@ -159,22 +165,25 @@ public Builder<K, V> ticker(Ticker ticker) {
       return this;
     }
 
-    /** Adds the functions to extract the primary key. */
+    /** Adds the function to extract the unique, stable, non-null primary key. */
     public Builder<K, V> primaryKey(Function<V, K> primary) {
-      this.primary = requireNonNull(primary);
+      checkState(!hasPrimary, "The primary indexing function was already defined");
+      indexers.addFirst(requireNonNull(primary));
+      hasPrimary = true;
       return this;
     }
 
-    /** Adds the functions to extract a secondary key. */
+    /** Adds a function to extract a unique secondary key or null if absent. */
     public Builder<K, V> addSecondaryKey(Function<V, K> secondary) {
-      secondaries.add(requireNonNull(secondary));
+      indexers.addLast(requireNonNull(secondary));
       return this;
     }
 
     public IndexedCache<K, V> build(Function<K, V> mappingFunction) {
-      requireNonNull(primary);
-      requireNonNull(mappingFunction);
-      return new IndexedCache<K, V>(cacheBuilder, mappingFunction, primary, secondaries.build());
+      checkState(hasPrimary, "The primary indexing function is required");
+      requireNonNull(mappingFunction, "The mapping function to load the value is required");
+      return new IndexedCache<K, V>(cacheBuilder, mappingFunction,
+          Collections.unmodifiableSequencedSet(indexers));
     }
   }
 }

gradle/libs.versions.toml

@@ -86,7 +86,7 @@ snakeyaml = "2.2"
 sonarqube = "5.0.0.4638"
 spotbugs-contrib = "7.6.4"
 spotbugs-core = "4.8.5"
-spotbugs-plugin = "6.0.16"
+spotbugs-plugin = "6.0.17"
 stream = "2.9.8"
 tcache = "2.0.1"
 testng = "7.10.2"