netudima commented on code in PR #4067: URL: https://github.com/apache/cassandra/pull/4067#discussion_r2050903569
########## src/java/org/apache/cassandra/db/virtual/AbstractLoggerVirtualTable.java: ########## @@ -0,0 +1,107 @@ +/* + * 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.cassandra.db.virtual; + +import java.util.Collections; +import java.util.LinkedList; +import java.util.List; + +import com.google.common.annotations.VisibleForTesting; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import ch.qos.logback.classic.spi.LoggingEvent; +import org.apache.cassandra.schema.TableMetadata; + +/** + * This table is inherently limited on number of rows it can hold. + * + * @param <U> type parameter saying what object is stored in internal bounded list for query purposes + */ +public abstract class AbstractLoggerVirtualTable<U> extends AbstractMutableVirtualTable +{ + private static final Logger logger = LoggerFactory.getLogger(AbstractLoggerVirtualTable.class); + + protected final List<U> buffer; + + @VisibleForTesting + protected static int resolveBufferSize(int wantedSize, int min, int max, int defaultSize) + { + return (wantedSize < min || wantedSize > max) ? defaultSize : wantedSize; + } + + protected AbstractLoggerVirtualTable(TableMetadata metadata, int maxSize) + { + super(metadata); + this.buffer = BoundedLinkedList.create(maxSize); + logger.debug("capacity of virtual table {} is set to be at most {} rows", metadata().toString(), maxSize); + } + + public void add(LoggingEvent event) + { + List<U> messages = getMessages(event); + if (messages != null) + { + // specifically calling buffer.add to reach BoundedLinkedList's add + // instead of linked list's addAll + for (U message : messages) + buffer.add(message); + } + } + + public abstract List<U> getMessages(LoggingEvent event); + + @Override + public void truncate() + { + buffer.clear(); + } + + @Override + public boolean allowFilteringImplicitly() + { + return false; + } + + private static final class BoundedLinkedList<T> extends LinkedList<T> + { + private final int maxSize; + + public static <T> List<T> create(int size) + { + return Collections.synchronizedList(new BoundedLinkedList<>(size)); + } + + private BoundedLinkedList(int maxSize) + { + this.maxSize = maxSize; + } + + @Override + public boolean add(T t) + { + if (size() == maxSize) Review Comment: can BoundedLinkedList.add be invoked concurrently? If yes - then it is better to at least to change the condition to >= to be more resilient in case of race conditions.. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: pr-unsubscr...@cassandra.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: pr-unsubscr...@cassandra.apache.org For additional commands, e-mail: pr-h...@cassandra.apache.org
