Java tutorial
/* * Copyright 2003-2016 MarkLogic Corporation * * 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 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.marklogic.contentpump; import java.io.IOException; import java.io.InputStreamReader; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import org.apache.commons.csv.CSVParser; import org.apache.commons.csv.CSVRecord; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FSDataInputStream; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.DefaultStringifier; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.InputSplit; import org.apache.hadoop.mapreduce.JobContext; import org.apache.hadoop.mapreduce.RecordReader; import org.apache.hadoop.mapreduce.TaskAttemptContext; import org.apache.hadoop.mapreduce.lib.input.FileSplit; import com.marklogic.contentpump.utilities.CSVParserFormatter; import com.marklogic.contentpump.utilities.DelimitedSplit; import com.marklogic.contentpump.utilities.DocBuilder; import com.marklogic.contentpump.utilities.EncodingUtil; import com.marklogic.mapreduce.DocumentURIWithSourceInfo; import com.marklogic.mapreduce.MarkLogicConstants; import com.marklogic.mapreduce.utilities.TextArrayWritable; /** * InputFormat for delimited text. Each line after metadata(1st line) is a * record. * * @author ali * */ public class DelimitedTextInputFormat extends FileAndDirectoryInputFormat<DocumentURIWithSourceInfo, Text> { public static final Log LOG = LogFactory.getLog(DelimitedTextInputFormat.class); @Override public RecordReader<DocumentURIWithSourceInfo, Text> createRecordReader(InputSplit split, TaskAttemptContext context) throws IOException, InterruptedException { if (isSplitInput(context.getConfiguration())) { return new SplitDelimitedTextReader<Text>(); } else { return new DelimitedTextReader<Text>(); } } private boolean isSplitInput(Configuration conf) { return conf.getBoolean(ConfigConstants.CONF_SPLIT_INPUT, false); } public List<InputSplit> getSplits(JobContext job) throws IOException { boolean delimSplit = isSplitInput(job.getConfiguration()); //if delimSplit is true, size of each split is determined by //Math.max(minSize, Math.min(maxSize, blockSize)) in FileInputFormat List<InputSplit> splits = super.getSplits(job); if (!delimSplit) { return splits; } if (splits.size() >= SPLIT_COUNT_LIMIT) { //if #splits > 1 million, there is enough parallelism //therefore no point to split LOG.warn("Exceeding SPLIT_COUNT_LIMIT, input_split is off:" + SPLIT_COUNT_LIMIT); DefaultStringifier.store(job.getConfiguration(), false, ConfigConstants.CONF_SPLIT_INPUT); return splits; } // add header info into splits List<InputSplit> populatedSplits = new ArrayList<InputSplit>(); LOG.info(splits.size() + " DelimitedSplits generated"); Configuration conf = job.getConfiguration(); char delimiter = 0; ArrayList<Text> hlist = new ArrayList<Text>(); for (InputSplit file : splits) { FileSplit fsplit = ((FileSplit) file); Path path = fsplit.getPath(); FileSystem fs = path.getFileSystem(conf); if (fsplit.getStart() == 0) { // parse the inSplit, get the header FSDataInputStream fileIn = fs.open(path); String delimStr = conf.get(ConfigConstants.CONF_DELIMITER, ConfigConstants.DEFAULT_DELIMITER); if (delimStr.length() == 1) { delimiter = delimStr.charAt(0); } else { LOG.error("Incorrect delimitor: " + delimiter + ". Expects single character."); } String encoding = conf.get(MarkLogicConstants.OUTPUT_CONTENT_ENCODING, MarkLogicConstants.DEFAULT_OUTPUT_CONTENT_ENCODING); InputStreamReader instream = new InputStreamReader(fileIn, encoding); CSVParser parser = new CSVParser(instream, CSVParserFormatter.getFormat(delimiter, DelimitedTextReader.encapsulator, true, true)); Iterator<CSVRecord> it = parser.iterator(); String[] header = null; if (it.hasNext()) { CSVRecord record = (CSVRecord) it.next(); Iterator<String> recordIterator = record.iterator(); int recordSize = record.size(); header = new String[recordSize]; for (int i = 0; i < recordSize; i++) { if (recordIterator.hasNext()) { header[i] = (String) recordIterator.next(); } else { throw new IOException("Record size doesn't match the real size"); } } EncodingUtil.handleBOMUTF8(header, 0); hlist.clear(); for (String s : header) { hlist.add(new Text(s)); } } instream.close(); } DelimitedSplit ds = new DelimitedSplit(new TextArrayWritable(hlist.toArray(new Text[hlist.size()])), path, fsplit.getStart(), fsplit.getLength(), fsplit.getLocations()); populatedSplits.add(ds); } return populatedSplits; } }