Java tutorial
/* * chombo: Hadoop Map Reduce utility * Author: Pranab Ghosh * * 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 org.chombo.mr; import java.io.IOException; import java.text.ParseException; import java.text.SimpleDateFormat; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.conf.Configured; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.NullWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.Reducer; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import org.apache.hadoop.util.Tool; import org.apache.hadoop.util.ToolRunner; import org.chombo.util.SecondarySort; import org.chombo.util.Tuple; import org.chombo.util.Utility; /** * Filters partitioned time sequence data. Filtering is on time field * @author pranab * */ public class TimeSequenceFilter extends Configured implements Tool { private static String configDelim = ","; @Override public int run(String[] args) throws Exception { Job job = new Job(getConf()); String jobName = "Time sequence to time gap sequence conversion"; job.setJobName(jobName); job.setJarByClass(TimeSequenceFilter.class); FileInputFormat.addInputPath(job, new Path(args[0])); FileOutputFormat.setOutputPath(job, new Path(args[1])); Utility.setConfiguration(job.getConfiguration(), "chombo"); job.setMapperClass(TimeGapSequenceGenerator.TimeGapMapper.class); job.setReducerClass(TimeSequenceFilter.FilterReducer.class); job.setMapOutputKeyClass(Tuple.class); job.setMapOutputValueClass(Tuple.class); job.setOutputKeyClass(NullWritable.class); job.setOutputValueClass(Text.class); job.setGroupingComparatorClass(SecondarySort.TuplePairGroupComprator.class); job.setPartitionerClass(SecondarySort.TuplePairPartitioner.class); int numReducer = job.getConfiguration().getInt("tsf.num.reducer", -1); numReducer = -1 == numReducer ? job.getConfiguration().getInt("num.reducer", 1) : numReducer; job.setNumReduceTasks(numReducer); int status = job.waitForCompletion(true) ? 0 : 1; return status; } /** * @author pranab * */ public static class FilterReducer extends Reducer<Tuple, Tuple, NullWritable, Text> { protected Text outVal = new Text(); protected StringBuilder stBld = new StringBuilder();; protected String fieldDelim; private int numIDFields; private int numAttributes; private String filterType; private Long minDateTime; private Long maxDateTime; private boolean toEmit; private long timeStamp; private static final String FIlT_EARLIEST = "earliest"; private static final String FIlT_LATEST = "latest"; private static final String FIlT_RANGE = "range"; /* (non-Javadoc) * @see org.apache.hadoop.mapreduce.Reducer#setup(org.apache.hadoop.mapreduce.Reducer.Context) */ protected void setup(Context context) throws IOException, InterruptedException { Configuration config = context.getConfiguration(); fieldDelim = config.get("field.delim.out", ","); filterType = config.get("tsf.filter.type"); if (filterType.equals(FIlT_RANGE)) { String dateFormatStr = config.get("tsf.date.format.str"); SimpleDateFormat dateFormat = dateFormatStr != null ? new SimpleDateFormat(dateFormatStr) : null; try { String minDateTimeStr = config.get("tsf.min.date.time"); minDateTime = getEpochTime(minDateTimeStr, dateFormat); String maxDateTimeStr = config.get("tsf.max.date.time"); maxDateTime = getEpochTime(maxDateTimeStr, dateFormat); if (null == minDateTimeStr && null == maxDateTime) { throw new IllegalStateException("date time range not specified"); } } catch (ParseException ex) { throw new IOException("Failed to parse date time", ex); } } numIDFields = Utility.intArrayFromString(config.get("tsf.id.field.ordinals"), configDelim).length; numAttributes = Utility.assertIntArrayConfigParam(config, "tsf.quant.attr.list", configDelim, "missing quant attribute list").length; } /** * @param dateTimeStr * @param dateFormat * @return * @throws ParseException */ private Long getEpochTime(String dateTimeStr, SimpleDateFormat dateFormat) throws ParseException { Long epochTime = null; if (null != dateTimeStr) { if (null != dateFormat) { epochTime = dateFormat.parse(dateTimeStr).getTime(); } else { epochTime = Long.parseLong(dateTimeStr); } } return epochTime; } /* (non-Javadoc) * @see org.apache.hadoop.mapreduce.Reducer#reduce(KEYIN, java.lang.Iterable, org.apache.hadoop.mapreduce.Reducer.Context) */ protected void reduce(Tuple key, Iterable<Tuple> values, Context context) throws IOException, InterruptedException { boolean first = true; Tuple latest = null; for (Tuple val : values) { if (filterType.equals(FIlT_EARLIEST) && first) { emit(key, val, context); break; } else if (filterType.equals(FIlT_LATEST)) { latest = val; } else if (filterType.equals(FIlT_RANGE)) { timeStamp = val.getLong(0); toEmit = (null == minDateTime || timeStamp > minDateTime) && (null == maxDateTime || timeStamp < maxDateTime); if (toEmit) { emit(key, val, context); } } else { throw new IllegalStateException("invalid fliter type"); } } if (null != latest) { emit(key, latest, context); } } /** * @param key * @param val * @param context * @throws IOException * @throws InterruptedException */ private void emit(Tuple key, Tuple val, Context context) throws IOException, InterruptedException { stBld.delete(0, stBld.length()); for (int i = 0; i < numIDFields; ++i) { stBld.append(key.getString(i)).append(fieldDelim); } stBld.append(val.getString(1)).append(fieldDelim); for (int i = 0; i < numAttributes; ++i) { stBld.append(val.getString(i + 2)).append(fieldDelim); } stBld.deleteCharAt(stBld.length() - 1); outVal.set(stBld.toString()); context.write(NullWritable.get(), outVal); } } /** * @param args */ public static void main(String[] args) throws Exception { int exitCode = ToolRunner.run(new TimeSequenceFilter(), args); System.exit(exitCode); } }