com.uber.hoodie.common.table.log.HoodieLogFormatReader Maven / Gradle / Ivy
/*
* Copyright (c) 2016 Uber Technologies, Inc. ([email protected])
*
* Licensed 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 com.uber.hoodie.common.table.log;
import com.uber.hoodie.common.model.HoodieLogFile;
import com.uber.hoodie.common.table.log.block.HoodieLogBlock;
import com.uber.hoodie.exception.HoodieIOException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.avro.Schema;
import org.apache.hadoop.fs.FileSystem;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
public class HoodieLogFormatReader implements HoodieLogFormat.Reader {
private final List logFiles;
// Readers for previously scanned log-files that are still open
private final List prevReadersInOpenState;
private HoodieLogFileReader currentReader;
private final FileSystem fs;
private final Schema readerSchema;
private final boolean readBlocksLazily;
private final boolean reverseLogReader;
private int bufferSize;
private static final Logger log = LogManager.getLogger(HoodieLogFormatReader.class);
HoodieLogFormatReader(FileSystem fs, List logFiles,
Schema readerSchema, boolean readBlocksLazily, boolean reverseLogReader, int bufferSize) throws IOException {
this.logFiles = logFiles;
this.fs = fs;
this.readerSchema = readerSchema;
this.readBlocksLazily = readBlocksLazily;
this.reverseLogReader = reverseLogReader;
this.bufferSize = bufferSize;
this.prevReadersInOpenState = new ArrayList<>();
if (logFiles.size() > 0) {
HoodieLogFile nextLogFile = logFiles.remove(0);
this.currentReader = new HoodieLogFileReader(fs, nextLogFile, readerSchema, bufferSize, readBlocksLazily, false);
}
}
@Override
/**
* Note : In lazy mode, clients must ensure close() should be called only after processing
* all log-blocks as the underlying inputstream will be closed.
* TODO: We can introduce invalidate() API at HoodieLogBlock and this object can call invalidate on
* all returned log-blocks so that we check this scenario specifically in HoodieLogBlock
*/
public void close() throws IOException {
for (HoodieLogFileReader reader : prevReadersInOpenState) {
reader.close();
}
prevReadersInOpenState.clear();
if (currentReader != null) {
currentReader.close();
}
}
@Override
public boolean hasNext() {
if (currentReader == null) {
return false;
} else if (currentReader.hasNext()) {
return true;
} else if (logFiles.size() > 0) {
try {
HoodieLogFile nextLogFile = logFiles.remove(0);
// First close previous reader only if readBlockLazily is true
if (!readBlocksLazily) {
this.currentReader.close();
} else {
this.prevReadersInOpenState.add(currentReader);
}
this.currentReader = new HoodieLogFileReader(fs, nextLogFile, readerSchema, bufferSize, readBlocksLazily,
false);
} catch (IOException io) {
throw new HoodieIOException("unable to initialize read with log file ", io);
}
log.info("Moving to the next reader for logfile " + currentReader.getLogFile());
return this.currentReader.hasNext();
}
return false;
}
@Override
public HoodieLogBlock next() {
return currentReader.next();
}
@Override
public HoodieLogFile getLogFile() {
return currentReader.getLogFile();
}
@Override
public void remove() {
}
}
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