1    package arraylists;
2    
3    import java.util.ArrayList;
4    import java.util.List;
5    import java.util.stream.Collectors;
6    
7    public class StreamArrayListProcessing {
8    
9        public static void main (String[] args) {
10           // POINT A: Add some strings which represent names to an ArrayList.
11           List<String> names = new ArrayList<>();
12           names.add("Holiday, Billie");
13           names.add("Claudel, Camille");
14           names.add("Picasso, Pablo");
15           names.add("Gallen-Kallela, Akseli");
16           names.add("Zotto, Osvaldo");
17   
18           //POINT B: Use map and the toList collector to create an ArrayList of just
19           // the first names of the names ArrayList. Use a for loop to print
20           // out the names, separated by spaces.
21           List <String> firstNamesList = names.stream()
22                   .map(n -> firstName(n))
23                   .collect(Collectors.toList());
24           System.out.print("First Names: ");
25           for (String firstName : firstNamesList) {
26               System.out.print(firstName + " ");
27           }
28           System.out.println();
29   
30           //POINT C: Use map and the joinin collector to create a String of just
31           // the first names of the names ArrayList with each name separated
32           // by a comma. Print it.
33           String firstNames = names.stream()
34                   .map(n -> firstName(n))
35                   .collect(Collectors.joining(", "));
36           System.out.println("First Names: " + firstNames);
37   
38           //POINT D: By analogy from point C, print a comma-separated list of the
39           // last names in the names ArrayList.
40           String lastNames = names.stream()
41                   .map(n -> lastName(n))
42                   .collect(Collectors.joining(", "));
43           System.out.println("Last Names: " + lastNames);
44   
45           //POINT E: Print a comma-separated list of all uppercase first names
46           // from the list of names in the names ArrayList.
47           String upperCaseFirstNames = names.stream()
48                   .map(n -> firstName(n))
49                   .map(n -> n.toUpperCase())
50                   .collect(Collectors.joining(", "));
51           System.out.println("Uppercase first names: " + upperCaseFirstNames);
52   
53           //POINT F: Print a comma-separated list of all hyphenated last names
54           // from the list of names in the names ArrayList.
55           String hyphenatedLastNames = names.stream()
56                   .map(n -> lastName(n))
57                   .filter(n -> n.contains("-"))
58                   .collect(Collectors.joining(", "));
59           System.out.println("Hyphenated last names: " + hyphenatedLastNames);
60   
61           //POINT G: Print the integer value of the total length of all names
62           // in the names ArrayList.
63           int totalLength = names.stream()
64                   .map(n -> n.length())
65                   .reduce(0, (n1, n2) -> n1 + n2);
66           System.out.println("Total length: " + totalLength);
67   
68           //POINT H: Print the integer value of the total length of all
69           // first names in the names ArrayList.
70           int totalFirstLength = firstNamesList.stream()
71                   .map(n -> n.length())
72                   .reduce(0, (n1, n2) -> n1 + n2);
73           System.out.println("Total first name length: " + totalFirstLength);
74   
75           //POINT I: Print the integer value of the product of the length
76           // of all first names in the names ArrayList.
77           int number = 1;
78           for (int i = 0; i < firstNamesList.size(); i = i + 1){
79               number = number * firstNamesList.get(i).length();
80           }
81           System.out.println("Product of the length of all first names: " + number);
82   
83       }
84   
85       private static String firstName(String directoryStyleName) {
86           int first = directoryStyleName.indexOf(" ");
87           String f = directoryStyleName.substring(first + 1);
88           return f;
89       }
90   
91       private static String lastName(String directoryStyleName) {
92           int last = directoryStyleName.indexOf(",");
93           String l = directoryStyleName.substring(0,last);
94           return l;
95       }
96   }
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