SmirAlex commented on code in PR #20196: URL: https://github.com/apache/flink/pull/20196#discussion_r933765687
########## flink-table/flink-table-common/src/main/java/org/apache/flink/table/connector/source/lookup/cache/DefaultLookupCache.java: ########## @@ -0,0 +1,270 @@ +/* + * 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.flink.table.connector.source.lookup.cache; + +import org.apache.flink.annotation.PublicEvolving; +import org.apache.flink.annotation.VisibleForTesting; +import org.apache.flink.configuration.ReadableConfig; +import org.apache.flink.metrics.Counter; +import org.apache.flink.metrics.ThreadSafeSimpleCounter; +import org.apache.flink.metrics.groups.CacheMetricGroup; +import org.apache.flink.table.data.RowData; +import org.apache.flink.util.clock.Clock; + +import org.apache.flink.shaded.guava30.com.google.common.base.Ticker; +import org.apache.flink.shaded.guava30.com.google.common.cache.Cache; +import org.apache.flink.shaded.guava30.com.google.common.cache.CacheBuilder; + +import javax.annotation.Nullable; + +import java.time.Duration; +import java.util.Collection; + +import static org.apache.flink.table.connector.source.lookup.LookupOptions.CACHE_TYPE; +import static org.apache.flink.table.connector.source.lookup.LookupOptions.LookupCacheType.PARTIAL; +import static org.apache.flink.table.connector.source.lookup.LookupOptions.PARTIAL_CACHE_CACHE_MISSING_KEY; +import static org.apache.flink.table.connector.source.lookup.LookupOptions.PARTIAL_CACHE_EXPIRE_AFTER_ACCESS; +import static org.apache.flink.table.connector.source.lookup.LookupOptions.PARTIAL_CACHE_EXPIRE_AFTER_WRITE; +import static org.apache.flink.table.connector.source.lookup.LookupOptions.PARTIAL_CACHE_MAX_ROWS; +import static org.apache.flink.util.Preconditions.checkArgument; +import static org.apache.flink.util.Preconditions.checkNotNull; + +/** Default implementation of {@link LookupCache}. */ +@PublicEvolving +public class DefaultLookupCache implements LookupCache { + private static final long serialVersionUID = 6839408984141411172L; + + // Configurations of the cache + private final Duration expireAfterAccessDuration; + private final Duration expireAfterWriteDuration; + private final Long maximumSize; + private final boolean cacheMissingKey; + + // The underlying Guava cache implementation + private transient Cache<RowData, Collection<RowData>> guavaCache; + + // Guava Ticker for testing expiration + private transient Ticker ticker; + + // For tracking cache metrics + private transient Counter hitCounter; + private transient Counter missCounter; + + private DefaultLookupCache( + Duration expireAfterAccessDuration, + Duration expireAfterWriteDuration, + Long maximumSize, + boolean cacheMissingKey) { + this.expireAfterAccessDuration = expireAfterAccessDuration; + this.expireAfterWriteDuration = expireAfterWriteDuration; + this.maximumSize = maximumSize; + this.cacheMissingKey = cacheMissingKey; + } + + /** Creates a builder for the cache. */ + public static Builder newBuilder() { + return new Builder(); + } + + public static DefaultLookupCache fromConfig(ReadableConfig config) { + checkArgument( + config.get(CACHE_TYPE).equals(PARTIAL), + "'%s' should be '%s' in order to build a default lookup cache", + CACHE_TYPE.key(), + PARTIAL); + return new DefaultLookupCache( + config.get(PARTIAL_CACHE_EXPIRE_AFTER_ACCESS), + config.get(PARTIAL_CACHE_EXPIRE_AFTER_WRITE), + config.get(PARTIAL_CACHE_MAX_ROWS), + config.get(PARTIAL_CACHE_CACHE_MISSING_KEY)); + } + + @Override + public void open(CacheMetricGroup metricGroup) { + synchronized (this) { + // The cache should already been opened if guava cache is not null + if (guavaCache != null) { + return; + } + // Initialize Guava cache + CacheBuilder<Object, Object> guavaCacheBuilder = CacheBuilder.newBuilder(); + if (expireAfterAccessDuration != null) { + guavaCacheBuilder.expireAfterAccess(expireAfterAccessDuration); + } + if (expireAfterWriteDuration != null) { + guavaCacheBuilder.expireAfterWrite(expireAfterWriteDuration); + } + if (maximumSize != null) { + guavaCacheBuilder.maximumSize(maximumSize); + } + if (ticker != null) { + guavaCacheBuilder.ticker(ticker); + } + guavaCache = guavaCacheBuilder.build(); + + // Initialize and register metrics + // Here we can't reuse Guava cache statistics because guavaCache#getIfPresent is not + // counted in the stat + hitCounter = new ThreadSafeSimpleCounter(); + missCounter = new ThreadSafeSimpleCounter(); + metricGroup.hitCounter(hitCounter); + metricGroup.missCounter(missCounter); + metricGroup.numCachedRecordsGauge(() -> guavaCache.size()); Review Comment: You can simplify to guavaCache::size -- This is an automated message from the Apache Git Service. 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