| /* |
| * Copyright 2009-2012 by The Regents of the University of California |
| * Licensed 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 from |
| * |
| * 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 edu.uci.ics.hyracks.hdfs.api; |
| |
| import edu.uci.ics.hyracks.api.comm.IFrameWriter; |
| import edu.uci.ics.hyracks.api.exceptions.HyracksDataException; |
| |
| /** |
| * Users need to implement this interface to use the HDFSReadOperatorDescriptor. |
| * |
| * @param <K> |
| * the key type |
| * @param <V> |
| * the value type |
| */ |
| public interface IKeyValueParser<K, V> { |
| |
| /** |
| * Initialize the key value parser. |
| * |
| * @param writer |
| * The hyracks writer for outputting data. |
| * @throws HyracksDataException |
| */ |
| public void open(IFrameWriter writer) throws HyracksDataException; |
| |
| /** |
| * Parse a key-value pair returned by HDFS record reader to a tuple. |
| * when the parsers' internal buffer is full, it can flush the buffer to the writer |
| * |
| * @param key |
| * The key returned from Hadoop's InputReader. |
| * @param value |
| * The value returned from Hadoop's InputReader. |
| * @param writer |
| * The hyracks writer for outputting data. |
| * @throws HyracksDataException |
| */ |
| public void parse(K key, V value, IFrameWriter writer) throws HyracksDataException; |
| |
| /** |
| * Flush the residual tuples in the internal buffer to the writer. |
| * This method is called in the close() of HDFSReadOperatorDescriptor. |
| * |
| * @param writer |
| * The hyracks writer for outputting data. |
| * @throws HyracksDataException |
| */ |
| public void close(IFrameWriter writer) throws HyracksDataException; |
| } |