org.apache.hadoop.hive.ql.io.orc.RecordReader 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.hadoop.hive.ql.io.orc;
import java.io.IOException;
import org.apache.hadoop.hive.ql.exec.vector.VectorizedRowBatch;
/**
* A row-by-row iterator for ORC files.
*/
public interface RecordReader {
/**
* Does the reader have more rows available.
* @return true if there are more rows
* @throws java.io.IOException
*/
boolean hasNext() throws IOException;
/**
* Read the next row.
* @param previous a row object that can be reused by the reader
* @return the row that was read
* @throws java.io.IOException
*/
Object next(Object previous) throws IOException;
/**
* Read the next row batch. The size of the batch to read cannot be controlled
* by the callers. Caller need to look at VectorizedRowBatch.size of the retunred
* object to know the batch size read.
* @param previousBatch a row batch object that can be reused by the reader
* @return the row batch that was read
* @throws java.io.IOException
*/
VectorizedRowBatch nextBatch(VectorizedRowBatch previousBatch) throws IOException;
/**
* Get the row number of the row that will be returned by the following
* call to next().
* @return the row number from 0 to the number of rows in the file
* @throws java.io.IOException
*/
long getRowNumber() throws IOException;
/**
* Get the progress of the reader through the rows.
* @return a fraction between 0.0 and 1.0 of rows read
* @throws java.io.IOException
*/
float getProgress() throws IOException;
/**
* Release the resources associated with the given reader.
* @throws java.io.IOException
*/
void close() throws IOException;
/**
* Seek to a particular row number.
*/
void seekToRow(long rowCount) throws IOException;
}