/**
* 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.crunch.io.parquet;
import com.google.common.collect.UnmodifiableIterator;
import java.io.IOException;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import org.apache.avro.generic.IndexedRecord;
import org.apache.crunch.CrunchRuntimeException;
import org.apache.crunch.io.FileReaderFactory;
import org.apache.crunch.io.impl.AutoClosingIterator;
import org.apache.crunch.types.avro.AvroType;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import parquet.avro.AvroReadSupport;
import parquet.hadoop.ParquetReader;
import parquet.schema.MessageType;
class AvroParquetFileReaderFactory<T> implements FileReaderFactory<T> {
private AvroType<T> avroType;
public AvroParquetFileReaderFactory(AvroType<T> avroType) {
this.avroType = avroType;
}
@Override
@SuppressWarnings("unchecked")
public Iterator<T> read(FileSystem fs, Path path) {
Path p = fs.makeQualified(path);
final ParquetReader reader;
try {
reader = new ParquetReader(p, new CrunchAvroReadSupport(avroType));
} catch (IOException e) {
throw new CrunchRuntimeException(e);
}
return new AutoClosingIterator<T>(reader, new UnmodifiableIterator<T>() {
private T next;
@Override
public boolean hasNext() {
if (next != null) {
return true;
}
try {
next = (T) reader.read();
} catch (IOException e) {
throw new CrunchRuntimeException(e);
}
return next != null;
}
@Override
public T next() {
if (hasNext()) {
T ret = next;
next = null;
return ret;
}
throw new NoSuchElementException();
}
});
}
static class CrunchAvroReadSupport<T extends IndexedRecord> extends AvroReadSupport<T> {
private AvroType<T> avroType;
public CrunchAvroReadSupport(AvroType<T> avroType) {
this.avroType = avroType;
}
@Override
public ReadContext init(Configuration configuration, Map<String, String> keyValueMetaData, MessageType fileSchema) {
if (avroType != null) {
setRequestedProjection(configuration, avroType.getSchema());
}
return super.init(configuration, keyValueMetaData, fileSchema);
}
}
}