org.apache.flink.table.filesystem.PartitionReader Maven / Gradle / Ivy
Show all versions of flink-table-runtime-blink_2.12 Show documentation
/*
* 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.flink.table.filesystem;
import org.apache.flink.annotation.Internal;
import javax.annotation.Nullable;
import java.io.Closeable;
import java.io.IOException;
import java.io.Serializable;
import java.util.List;
/**
* Reader that reads record from given partitions.
*
* This reader should only use in non-parallel instance, e.g. : used by lookup function.
*
* @param
The type of partition.
* @param The type of returned record.
*/
@Internal
public interface PartitionReader extends Closeable, Serializable {
/** Opens the reader with given partitions. */
void open(List
partitions) throws IOException;
/**
* Reads the next record from the partitions.
*
*
When this method is called, the reader it guaranteed to be opened.
*
* @param reuse Object that may be reused.
* @return Read record.
*/
@Nullable
OUT read(OUT reuse) throws IOException;
/**
* Close the reader, this method should release all resources.
*
*
When this method is called, the reader it guaranteed to be opened.
*/
@Override
void close() throws IOException;
}