/*
* 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 com.aliyun.odps.io;
import java.io.BufferedOutputStream;
import java.io.IOException;
/**
* OutputBlobWritable表示ODPS表或分区中列类型为blob的输出接口, 该接口只能用于
* {@link com.aliyun.odps.mapreduce.Reducer}向 {@link com.aliyun.odps.Record}
* 中写入blob类型的列.
* <p>
* 用法示例：
*
* <pre>
* @Override
* public void reduce(KEYIN key, Iterable<VALUEIN> values,
* MapContext<KEYIN, VALUEIN> context) throws IOException {
* Record outputRecord = context.createOutputRecord();
* OutputBlobWritable blob = outputRecord.get(0);
* BufferedOutputStream out = blob.getOutputStream();
* // 使用out.write向blob中写入数据
* out.close();
* }
* </pre>
*
* 从上面的示例看出, 从{@link com.aliyun.odps.Record}获得OutputBlobWritable接口,
* 调用OutputBlobWritable的 getOutputStream获得BufferedOutputStream后，即可进行写入数据.
* </p>
*/
public interface OutputBlobWritable extends WritableComparable {
/**
* getOutputStream方法获取可以写入blob的{@link BufferedOutputStream}接口
*
* @return blob列对应的{@link BufferedOutputStream}
* @throws IOException
*/
public BufferedOutputStream getOutputStream() throws IOException;
}