yifan-c commented on code in PR #138: URL: https://github.com/apache/cassandra-analytics/pull/138#discussion_r2326422543
########## cassandra-four-zero-bridge/src/main/java/org/apache/cassandra/spark/reader/IndexSummaryComponent.java: ########## @@ -0,0 +1,102 @@ +/* + * 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.spark.reader; + +import java.io.DataInputStream; +import java.io.IOException; +import java.io.InputStream; + +import org.apache.cassandra.db.DecoratedKey; +import org.apache.cassandra.dht.IPartitioner; +import org.apache.cassandra.io.sstable.IndexSummary; +import org.apache.cassandra.utils.ByteBufferUtil; +import org.jetbrains.annotations.Nullable; + +public class IndexSummaryComponent implements AutoCloseable +{ + private final IndexSummary indexSummary; + private final DecoratedKey firstKey; + private final DecoratedKey lastKey; + + /** + * Read and deserialize the Summary.db file + * + * @param summaryStream input stream for Summary.db file + * @param partitioner token partitioner + * @param minIndexInterval min index interval + * @param maxIndexInterval max index interval + * @return Summary object + * @throws IOException io exception + */ + @Nullable + static IndexSummaryComponent readSummary(InputStream summaryStream, + IPartitioner partitioner, + int minIndexInterval, + int maxIndexInterval) throws IOException + { + if (summaryStream == null) + { + return null; + } + + try (DataInputStream is = new DataInputStream(summaryStream)) + { + IndexSummary indexSummary = IndexSummary.serializer.deserialize(is, partitioner, minIndexInterval, maxIndexInterval); + DecoratedKey firstKey = partitioner.decorateKey(ByteBufferUtil.readWithLength(is)); + DecoratedKey lastKey = partitioner.decorateKey(ByteBufferUtil.readWithLength(is)); + return new IndexSummaryComponent(indexSummary, firstKey, lastKey); + } + } + + IndexSummaryComponent(IndexSummary indexSummary, + DecoratedKey firstKey, + DecoratedKey lastKey) + { + this.indexSummary = indexSummary; + this.firstKey = firstKey; + this.lastKey = lastKey; + } + + /** + * Get a shared copy of the IndexSummary, whose reference count is incremented. + * It is important to close the shared copy to decrement the reference count. + * @return a shared copy of the IndexSummary object + */ + public IndexSummary summarySharedCopy() + { + return indexSummary.sharedCopy(); Review Comment: get a shared copy, so that if `IndexSummaryComponent` is closed, the underlying `indexSummary` is still not freed (since reference count > 0) -- 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: commits-unsubscr...@cassandra.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org
