Reimplement Exercise 17.10 using parallelstreams. Use the Date/Time API timing techniques to compare the time required for the sequential and parallel versions of the program.

Exercise 17.10

Modify the program of Fig. 17.22 to summarize the number of occurrences of every character in the file.

Fig. 17.22

Transcribed Image Text:

1234 3 import java.io.IOException; 4 import java.nio.file.Files; 5 import java.nio.file.Paths; 6 import java.util.Map; 7 import java.util.TreeMap; import 8 9 13 14 15 10 II public class StreamOfLines { 12 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 // Fig. 17.22: StreamOfLines.java // Counting word occurrences in a text file. NNNNNNMMMM MM 33 34 java.util.regex.Pattern; import java.util.stream.Collectors; 35 } public static void main(String[] args) throws IOException { // Regex that matches one or more consecutive whitespace characters Pattern pattern = Pattern.compile("\\s+"); // count occurrences of each word in a Stream sorted by word Map wordCounts = Files.lines (Paths.get("Chapter 2Paragraph.txt")) .flatMap (line -> pattern.splitAsStream (line)) .collect(Collectors.grouping By (String: :toLowerCase, TreeMap::new, Collectors.counting (())); // display the words grouped by starting letter wordCounts.entrySet() .stream() .collect( Collectors.grouping By (entry entry.getKey().charAt(0), TreeMap:: new, Collectors.toList())) .forEach ((letter, wordList) -> { System.out.printf("%n%C%n", letter); wordList.stream().forEach (word > System.out.printf( "%13s: %d%n", word.getKey(), word.getValue(())); });