| /** |
| * 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.mapreduce.lib.input; |
| |
| import java.io.IOException; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.io.Text; |
| import org.apache.hadoop.mapreduce.InputSplit; |
| import org.apache.hadoop.mapreduce.RecordReader; |
| import org.apache.hadoop.mapreduce.TaskAttemptContext; |
| |
| /** |
| * This class treats a line in the input as a key/value pair separated by a |
| * separator character. The separator can be specified in config file |
| * under the attribute name mapreduce.input.keyvaluelinerecordreader.key.value.separator. The default |
| * separator is the tab character ('\t'). |
| */ |
| @InterfaceAudience.Public |
| @InterfaceStability.Stable |
| public class KeyValueLineRecordReader extends RecordReader<Text, Text> { |
| public static final String KEY_VALUE_SEPERATOR = |
| "mapreduce.input.keyvaluelinerecordreader.key.value.separator"; |
| |
| private final LineRecordReader lineRecordReader; |
| |
| private byte separator = (byte) '\t'; |
| |
| private Text innerValue; |
| |
| private Text key; |
| |
| private Text value; |
| |
| public Class getKeyClass() { return Text.class; } |
| |
| public KeyValueLineRecordReader(Configuration conf) |
| throws IOException { |
| |
| lineRecordReader = new LineRecordReader(); |
| String sepStr = conf.get(KEY_VALUE_SEPERATOR, "\t"); |
| this.separator = (byte) sepStr.charAt(0); |
| } |
| |
| public void initialize(InputSplit genericSplit, |
| TaskAttemptContext context) throws IOException { |
| lineRecordReader.initialize(genericSplit, context); |
| } |
| |
| public static int findSeparator(byte[] utf, int start, int length, |
| byte sep) { |
| for (int i = start; i < (start + length); i++) { |
| if (utf[i] == sep) { |
| return i; |
| } |
| } |
| return -1; |
| } |
| |
| public static void setKeyValue(Text key, Text value, byte[] line, |
| int lineLen, int pos) { |
| if (pos == -1) { |
| key.set(line, 0, lineLen); |
| value.set(""); |
| } else { |
| key.set(line, 0, pos); |
| value.set(line, pos + 1, lineLen - pos - 1); |
| } |
| } |
| /** Read key/value pair in a line. */ |
| public synchronized boolean nextKeyValue() |
| throws IOException { |
| byte[] line = null; |
| int lineLen = -1; |
| if (lineRecordReader.nextKeyValue()) { |
| innerValue = lineRecordReader.getCurrentValue(); |
| line = innerValue.getBytes(); |
| lineLen = innerValue.getLength(); |
| } else { |
| return false; |
| } |
| if (line == null) |
| return false; |
| if (key == null) { |
| key = new Text(); |
| } |
| if (value == null) { |
| value = new Text(); |
| } |
| int pos = findSeparator(line, 0, lineLen, this.separator); |
| setKeyValue(key, value, line, lineLen, pos); |
| return true; |
| } |
| |
| public Text getCurrentKey() { |
| return key; |
| } |
| |
| public Text getCurrentValue() { |
| return value; |
| } |
| |
| public float getProgress() throws IOException { |
| return lineRecordReader.getProgress(); |
| } |
| |
| public synchronized void close() throws IOException { |
| lineRecordReader.close(); |
| } |
| } |