org.apache.hudi.common.util.ParquetReaderIterator Maven / Gradle / Ivy
/*
* 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.hudi.common.util;
import org.apache.hudi.common.util.collection.ClosableIterator;
import org.apache.hudi.common.util.queue.BoundedInMemoryQueue;
import org.apache.hudi.exception.HoodieException;
import org.apache.parquet.hadoop.ParquetReader;
import java.io.IOException;
/**
* This class wraps a parquet reader and provides an iterator based api to read from a parquet file. This is used in
* {@link BoundedInMemoryQueue}
*/
public class ParquetReaderIterator implements ClosableIterator {
// Parquet reader for an existing parquet file
private final ParquetReader parquetReader;
// Holds the next entry returned by the parquet reader
private T next;
public ParquetReaderIterator(ParquetReader parquetReader) {
this.parquetReader = parquetReader;
}
@Override
public boolean hasNext() {
try {
// To handle when hasNext() is called multiple times for idempotency and/or the first time
if (this.next == null) {
this.next = parquetReader.read();
}
return this.next != null;
} catch (Exception e) {
FileIOUtils.closeQuietly(parquetReader);
throw new HoodieException("unable to read next record from parquet file ", e);
}
}
@Override
public T next() {
try {
// To handle case when next() is called before hasNext()
if (this.next == null) {
if (!hasNext()) {
throw new HoodieException("No more records left to read from parquet file");
}
}
T retVal = this.next;
this.next = null;
return retVal;
} catch (Exception e) {
FileIOUtils.closeQuietly(parquetReader);
throw new HoodieException("unable to read next record from parquet file ", e);
}
}
public void close() {
try {
parquetReader.close();
} catch (IOException e) {
throw new HoodieException("Exception while closing the parquet reader", e);
}
}
}