Introduce constants for trivial QueryCachingPolicies (#86344)

Just a random find:
Cleaning this up, mainly to simplify the already far too complex `IndexShard` constructor.

server/src/main/java/org/elasticsearch/index/cache/query/TrivialQueryCachingPolicy.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+package org.elasticsearch.index.cache.query;
+
+import org.apache.lucene.search.Query;
+import org.apache.lucene.search.QueryCachingPolicy;
+
+public enum TrivialQueryCachingPolicy implements QueryCachingPolicy {
+    ALWAYS(true),
+    NEVER(false);
+
+    private final boolean shouldCache;
+
+    TrivialQueryCachingPolicy(boolean shouldCache) {
+        this.shouldCache = shouldCache;
+    }
+
+    @Override
+    public void onUse(Query query) {}
+
+    @Override
+    public boolean shouldCache(Query query) {
+        return shouldCache;
+    }
+}

server/src/main/java/org/elasticsearch/index/engine/InternalEngine.java

@@ -29,7 +29,6 @@
 import org.apache.lucene.search.DocIdSetIterator;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.Query;
-import org.apache.lucene.search.QueryCachingPolicy;
 import org.apache.lucene.search.ReferenceManager;
 import org.apache.lucene.search.ScoreMode;
 import org.apache.lucene.search.Scorer;
@@ -63,6 +62,7 @@
 import org.elasticsearch.core.SuppressForbidden;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.VersionType;
+import org.elasticsearch.index.cache.query.TrivialQueryCachingPolicy;
 import org.elasticsearch.index.mapper.DocumentParser;
 import org.elasticsearch.index.mapper.IdFieldMapper;
 import org.elasticsearch.index.mapper.LuceneDocument;
@@ -638,18 +638,6 @@ private ExternalReaderManager createReaderManager(RefreshWarmerListener external
         }
     }
 
-    private static final QueryCachingPolicy NEVER_CACHE_POLICY = new QueryCachingPolicy() {
-        @Override
-        public void onUse(Query query) {
-
-        }
-
-        @Override
-        public boolean shouldCache(Query query) {
-            return false;
-        }
-    };
-
     public final AtomicLong translogGetCount = new AtomicLong(); // number of times realtime get was done on translog
     public final AtomicLong translogInMemorySegmentsCount = new AtomicLong(); // number of times in-memory index needed to be created
 
@@ -675,7 +663,7 @@ private GetResult getFromTranslog(
             ElasticsearchDirectoryReader.wrap(inMemoryReader, shardId),
             config().getSimilarity(),
             null /*query cache disabled*/,
-            NEVER_CACHE_POLICY,
+            TrivialQueryCachingPolicy.NEVER,
             inMemoryReader
         );
         final Searcher wrappedSearcher = searcherWrapper.apply(searcher);

server/src/main/java/org/elasticsearch/index/shard/IndexShard.java

@@ -19,7 +19,6 @@
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.SegmentInfos;
 import org.apache.lucene.index.Term;
-import org.apache.lucene.search.Query;
 import org.apache.lucene.search.QueryCachingPolicy;
 import org.apache.lucene.search.ReferenceManager;
 import org.apache.lucene.search.Sort;
@@ -80,6 +79,7 @@
 import org.elasticsearch.index.bulk.stats.ShardBulkStats;
 import org.elasticsearch.index.cache.IndexCache;
 import org.elasticsearch.index.cache.bitset.ShardBitsetFilterCache;
+import org.elasticsearch.index.cache.query.TrivialQueryCachingPolicy;
 import org.elasticsearch.index.cache.request.ShardRequestCache;
 import org.elasticsearch.index.codec.CodecService;
 import org.elasticsearch.index.engine.CommitStats;
@@ -373,17 +373,7 @@ public IndexShard(
         // the query cache is a node-level thing, however we want the most popular filters
         // to be computed on a per-shard basis
         if (IndexModule.INDEX_QUERY_CACHE_EVERYTHING_SETTING.get(settings)) {
-            cachingPolicy = new QueryCachingPolicy() {
-                @Override
-                public void onUse(Query query) {
-
-                }
-
-                @Override
-                public boolean shouldCache(Query query) {
-                    return true;
-                }
-            };
+            cachingPolicy = TrivialQueryCachingPolicy.ALWAYS;
         } else {
             cachingPolicy = new UsageTrackingQueryCachingPolicy();
         }

server/src/test/java/org/elasticsearch/index/engine/CompletionStatsCacheTests.java

@@ -13,13 +13,12 @@
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.IndexWriterConfig;
-import org.apache.lucene.search.Query;
-import org.apache.lucene.search.QueryCachingPolicy;
 import org.apache.lucene.search.suggest.document.Completion90PostingsFormat;
 import org.apache.lucene.search.suggest.document.SuggestField;
 import org.apache.lucene.store.Directory;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.core.IOUtils;
+import org.elasticsearch.index.cache.query.TrivialQueryCachingPolicy;
 import org.elasticsearch.search.suggest.completion.CompletionStats;
 import org.elasticsearch.test.ESTestCase;
 
@@ -53,16 +52,6 @@ public PostingsFormat getPostingsFormatForField(String field) {
             }
         });
 
-        final QueryCachingPolicy queryCachingPolicy = new QueryCachingPolicy() {
-            @Override
-            public void onUse(Query query) {}
-
-            @Override
-            public boolean shouldCache(Query query) {
-                return false;
-            }
-        };
-
         try (Directory directory = newDirectory(); IndexWriter indexWriter = new IndexWriter(directory, indexWriterConfig)) {
 
             final Document document = new Document();
@@ -79,7 +68,7 @@ public boolean shouldCache(Query query) {
                 openCloseCounter.countOpened();
                 try {
                     final DirectoryReader directoryReader = DirectoryReader.open(indexWriter);
-                    return new Engine.Searcher("test", directoryReader, null, null, queryCachingPolicy, () -> {
+                    return new Engine.Searcher("test", directoryReader, null, null, TrivialQueryCachingPolicy.NEVER, () -> {
                         openCloseCounter.countClosed();
                         IOUtils.close(directoryReader);
                     });

server/src/test/java/org/elasticsearch/indices/IndicesQueryCacheTests.java

@@ -19,7 +19,6 @@
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
-import org.apache.lucene.search.QueryCachingPolicy;
 import org.apache.lucene.search.QueryVisitor;
 import org.apache.lucene.search.ScoreMode;
 import org.apache.lucene.search.Scorer;
@@ -30,6 +29,7 @@
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.core.IOUtils;
 import org.elasticsearch.index.cache.query.QueryCacheStats;
+import org.elasticsearch.index.cache.query.TrivialQueryCachingPolicy;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.test.ESTestCase;
 
@@ -82,20 +82,6 @@ public boolean isCacheable(LeafReaderContext ctx) {
 
     }
 
-    private static QueryCachingPolicy alwaysCachePolicy() {
-        return new QueryCachingPolicy() {
-            @Override
-            public void onUse(Query query) {
-
-            }
-
-            @Override
-            public boolean shouldCache(Query query) {
-                return true;
-            }
-        };
-    }
-
     public void testBasics() throws IOException {
         Directory dir = newDirectory();
         IndexWriter w = new IndexWriter(dir, newIndexWriterConfig());
@@ -105,7 +91,7 @@ public void testBasics() throws IOException {
         ShardId shard = new ShardId("index", "_na_", 0);
         r = ElasticsearchDirectoryReader.wrap(r, shard);
         IndexSearcher s = new IndexSearcher(r);
-        s.setQueryCachingPolicy(alwaysCachePolicy());
+        s.setQueryCachingPolicy(TrivialQueryCachingPolicy.ALWAYS);
 
         Settings settings = Settings.builder()
             .put(IndicesQueryCache.INDICES_CACHE_QUERY_COUNT_SETTING.getKey(), 10)
@@ -176,7 +162,7 @@ public void testTwoShards() throws IOException {
         ShardId shard1 = new ShardId("index", "_na_", 0);
         r1 = ElasticsearchDirectoryReader.wrap(r1, shard1);
         IndexSearcher s1 = new IndexSearcher(r1);
-        s1.setQueryCachingPolicy(alwaysCachePolicy());
+        s1.setQueryCachingPolicy(TrivialQueryCachingPolicy.ALWAYS);
 
         Directory dir2 = newDirectory();
         IndexWriter w2 = new IndexWriter(dir2, newIndexWriterConfig());
@@ -186,7 +172,7 @@ public void testTwoShards() throws IOException {
         ShardId shard2 = new ShardId("index", "_na_", 1);
         r2 = ElasticsearchDirectoryReader.wrap(r2, shard2);
         IndexSearcher s2 = new IndexSearcher(r2);
-        s2.setQueryCachingPolicy(alwaysCachePolicy());
+        s2.setQueryCachingPolicy(TrivialQueryCachingPolicy.ALWAYS);
 
         Settings settings = Settings.builder()
             .put(IndicesQueryCache.INDICES_CACHE_QUERY_COUNT_SETTING.getKey(), 10)
@@ -304,7 +290,7 @@ public void testStatsOnEviction() throws IOException {
         ShardId shard1 = new ShardId("index", "_na_", 0);
         r1 = ElasticsearchDirectoryReader.wrap(r1, shard1);
         IndexSearcher s1 = new IndexSearcher(r1);
-        s1.setQueryCachingPolicy(alwaysCachePolicy());
+        s1.setQueryCachingPolicy(TrivialQueryCachingPolicy.ALWAYS);
 
         Directory dir2 = newDirectory();
         IndexWriter w2 = new IndexWriter(dir2, newIndexWriterConfig());
@@ -314,7 +300,7 @@ public void testStatsOnEviction() throws IOException {
         ShardId shard2 = new ShardId("index", "_na_", 1);
         r2 = ElasticsearchDirectoryReader.wrap(r2, shard2);
         IndexSearcher s2 = new IndexSearcher(r2);
-        s2.setQueryCachingPolicy(alwaysCachePolicy());
+        s2.setQueryCachingPolicy(TrivialQueryCachingPolicy.ALWAYS);
 
         Settings settings = Settings.builder()
             .put(IndicesQueryCache.INDICES_CACHE_QUERY_COUNT_SETTING.getKey(), 10)
@@ -389,15 +375,7 @@ public void testDelegatesScorerSupplier() throws Exception {
         ShardId shard = new ShardId("index", "_na_", 0);
         r = ElasticsearchDirectoryReader.wrap(r, shard);
         IndexSearcher s = new IndexSearcher(r);
-        s.setQueryCachingPolicy(new QueryCachingPolicy() {
-            @Override
-            public boolean shouldCache(Query query) throws IOException {
-                return false; // never cache
-            }
-
-            @Override
-            public void onUse(Query query) {}
-        });
+        s.setQueryCachingPolicy(TrivialQueryCachingPolicy.NEVER);
 
         Settings settings = Settings.builder()
             .put(IndicesQueryCache.INDICES_CACHE_QUERY_COUNT_SETTING.getKey(), 10)

server/src/test/java/org/elasticsearch/search/profile/query/QueryProfilerTests.java

@@ -21,7 +21,6 @@
 import org.apache.lucene.search.LRUQueryCache;
 import org.apache.lucene.search.LeafCollector;
 import org.apache.lucene.search.Query;
-import org.apache.lucene.search.QueryCachingPolicy;
 import org.apache.lucene.search.QueryVisitor;
 import org.apache.lucene.search.ScoreMode;
 import org.apache.lucene.search.Scorer;
@@ -35,6 +34,7 @@
 import org.apache.lucene.tests.search.RandomApproximationQuery;
 import org.apache.lucene.tests.util.TestUtil;
 import org.elasticsearch.core.IOUtils;
+import org.elasticsearch.index.cache.query.TrivialQueryCachingPolicy;
 import org.elasticsearch.search.internal.ContextIndexSearcher;
 import org.elasticsearch.search.profile.ProfileResult;
 import org.elasticsearch.test.ESTestCase;
@@ -75,7 +75,7 @@ public static void setup() throws IOException {
             reader,
             IndexSearcher.getDefaultSimilarity(),
             IndexSearcher.getDefaultQueryCache(),
-            ALWAYS_CACHE_POLICY,
+            TrivialQueryCachingPolicy.ALWAYS,
             true
         );
     }
@@ -296,15 +296,4 @@ public void testScorerSupplier() throws IOException {
         dir.close();
     }
 
-    private static final QueryCachingPolicy ALWAYS_CACHE_POLICY = new QueryCachingPolicy() {
-
-        @Override
-        public void onUse(Query query) {}
-
-        @Override
-        public boolean shouldCache(Query query) throws IOException {
-            return true;
-        }
-
-    };
 }

test/framework/src/main/java/org/elasticsearch/search/aggregations/AggregatorTestCase.java

@@ -28,7 +28,6 @@
 import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.QueryCache;
-import org.apache.lucene.search.QueryCachingPolicy;
 import org.apache.lucene.search.ScoreMode;
 import org.apache.lucene.search.Sort;
 import org.apache.lucene.search.SortField;
@@ -69,6 +68,7 @@
 import org.elasticsearch.index.analysis.NamedAnalyzer;
 import org.elasticsearch.index.cache.bitset.BitsetFilterCache;
 import org.elasticsearch.index.cache.query.DisabledQueryCache;
+import org.elasticsearch.index.cache.query.TrivialQueryCachingPolicy;
 import org.elasticsearch.index.fielddata.IndexFieldData;
 import org.elasticsearch.index.fielddata.IndexFieldDataCache;
 import org.elasticsearch.index.mapper.BinaryFieldMapper;
@@ -372,23 +372,13 @@ private SubSearchContext buildSubSearchContext(
     ) {
         SearchContext ctx = mock(SearchContext.class);
         QueryCache queryCache = new DisabledQueryCache(indexSettings);
-        QueryCachingPolicy queryCachingPolicy = new QueryCachingPolicy() {
-            @Override
-            public void onUse(Query query) {}
-
-            @Override
-            public boolean shouldCache(Query query) {
-                // never cache a query
-                return false;
-            }
-        };
         try {
             when(ctx.searcher()).thenReturn(
                 new ContextIndexSearcher(
                     searchExecutionContext.searcher().getIndexReader(),
                     searchExecutionContext.searcher().getSimilarity(),
                     queryCache,
-                    queryCachingPolicy,
+                    TrivialQueryCachingPolicy.NEVER,
                     false
                 )
             );