org.apache.hudi.hadoop.RecordReaderValueIterator 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.hadoop;
import org.apache.hudi.exception.HoodieException;
import org.apache.hadoop.mapred.RecordReader;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import java.io.IOException;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* Provides Iterator Interface to iterate value entries read from record reader.
*
* @param Key Type
* @param Value Type
*/
public class RecordReaderValueIterator implements Iterator {
private static final Logger LOG = LogManager.getLogger(RecordReaderValueIterator.class);
private final RecordReader reader;
private V nextVal = null;
/**
* Construct RecordReaderValueIterator.
*
* @param reader reader
*/
public RecordReaderValueIterator(RecordReader reader) {
this.reader = reader;
}
@Override
public boolean hasNext() {
if (nextVal == null) {
K key = reader.createKey();
V val = reader.createValue();
try {
boolean notDone = reader.next(key, val);
if (!notDone) {
return false;
}
this.nextVal = val;
} catch (IOException e) {
LOG.error("Got error reading next record from record reader");
throw new HoodieException(e);
}
}
return true;
}
@Override
public V next() {
if (!hasNext()) {
throw new NoSuchElementException("Make sure you are following iterator contract.");
}
V retVal = this.nextVal;
this.nextVal = null;
return retVal;
}
public void close() throws IOException {
this.reader.close();
}
}