package org.p7h.udacityhadoop.p1; import java.io.IOException; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.DoubleWritable; import org.apache.hadoop.io.LongWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.Mapper; import org.apache.hadoop.mapreduce.Reducer; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import org.apache.hadoop.mapreduce.lib.input.TextInputFormat; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat; /** * Find the monetary value for the highest individual sale for each separate store. * Format of each line is: * date\ttime\tstore name\titem description\tcost\tmethod of payment */ public final class P1Q2 { public final static void main(final String[] args) throws Exception { final Configuration conf = new Configuration(); final Job job = new Job(conf, "P1Q2"); job.setJarByClass(P1Q2.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(DoubleWritable.class); job.setMapperClass(P1Q2Map.class); job.setCombinerClass(P1Q2Reduce.class); job.setReducerClass(P1Q2Reduce.class); job.setInputFormatClass(TextInputFormat.class); job.setOutputFormatClass(TextOutputFormat.class); FileInputFormat.addInputPath(job, new Path(args[0])); FileOutputFormat.setOutputPath(job, new Path(args[1])); job.waitForCompletion(true); } public static final class P1Q2Map extends Mapper<LongWritable, Text, Text, DoubleWritable> { private final Text word = new Text(); public final void map(final LongWritable key, final Text value, final Context context) throws IOException, InterruptedException { final String line = value.toString(); final String[] data = line.trim().split("\t"); if (data.length == 6) { final String product = data[2]; final double sales = Double.parseDouble(data[4]); word.set(product); context.write(word, new DoubleWritable(sales)); } } } public static final class P1Q2Reduce extends Reducer<Text, DoubleWritable, Text, DoubleWritable> { public final void reduce(final Text key, final Iterable<DoubleWritable> values, final Context context) throws IOException, InterruptedException { double highestSale = 0.0; double currentSale; for (DoubleWritable val : values) { currentSale = val.get(); if (highestSale < currentSale) { highestSale = currentSale; } } context.write(key, new DoubleWritable(highestSale)); } } }