1    /* 
2     * A program to perform some basic operations on a list of storage 
3     * using Java streams 
4     */
5    package arraylists;
6    
7    import java.util.ArrayList;
8    import java.util.List;
9    import java.util.stream.Collectors;
10   
11   public class StreamArrayListProcessing {
12   
13       public static void main(String[] args) {
14           // POINT A: Add some strings which represent names to an ArrayList
15           List<String> names = new ArrayList<>();
16           names.add("Holiday, Billie");
17           names.add("Claudel, Camille");
18           names.add("Picasso, Pablo");
19           names.add("Gallen-Kallela, Akseli");
20           names.add("Zotto, Osvaldo");
21           names.add("Curry, Stephen");
22           names.add("Thompson, Klay");
23           names.add("Green, Draymond");
24           names.add("Russel, Diangelo");
25   
26           // POINT B: Use map and the toList collector to create an ArrayList of just the fist names of the name ArrayList. use a for loop to print out the names, separated by spaces
27           List<String> firstNamesList = names.stream()
28                   .map(n -> firstName(n))
29                   .collect(Collectors.toList());
30   
31           System.out.println("First name: ");
32           for (String firstName : firstNamesList) {
33               System.out.print(firstName + " ");
34           }
35           System.out.println();
36   
37           // POINT C: Use map and the joining collector to create a String of just the first names of the names ArrayList with each name separated by a comma. Print it.
38           String firstNames = names.stream()
39                   .map(n -> firstName(n))
40                   .collect(Collectors.joining(", "));
41   
42           System.out.println("First names: " + firstNames);
43   
44           // POINT D: By analogy from point C, print a comma-separated list of the last names in the names ArrayList.
45           String lastNames = names.stream()
46                   .map(n -> lastName(n))
47                   .collect(Collectors.joining(", "));
48   
49           System.out.println("Last names: " + lastNames);
50   
51           // POINT E: Print a comma-separated list of all uppercase first names from the list of names in the names ArrayList.
52           String upperCaseFirstNames = names.stream()
53                   .map(n -> firstName(n))
54                   .map(n -> n.toUpperCase())
55                   .collect(Collectors.joining(", "));
56   
57           System.out.println("Uppercase first name: " + upperCaseFirstNames);
58   
59           // POINT F: Print a comma-separated list of all hyphenated list of all hyphenated last names from the list of names in the names ArrayList.
60           String hyphenatedLastNames = names.stream()
61                   .map(n -> lastName(n))
62                   .filter(n -> n.contains("-"))
63                   .collect(Collectors.joining(", "));
64   
65           System.out.println("Hyphenated last names: " + hyphenatedLastNames);
66   
67           // POINT G: Print the integer value of the total length of all names in the names ArrayList.
68           int totalLength = names.stream()
69                   .map(n -> n.length())
70                   .reduce(0, (n1, n2) -> n1 + n2);
71   
72           System.out.println("Total length: " + totalLength);
73   
74           // POINT H: Print the integer value of the total length of all first names in the name ArrayList.
75           int totalFirstNamesLength = names.stream()
76                   .map(n -> firstName(n))
77                   .map(n -> n.length())
78                   .reduce(0, (n1, n2) -> n1 + n2);
79   
80           System.out.println("Total first names length: " + totalFirstNamesLength);
81   
82           // POINT I: Print the integer value of the product of the length of all first names in the name ArrayList.
83           int totalLengthProduct = names.stream()
84                   .map(n -> n.length())
85                   .reduce(0, (n1, n2) -> n1 * n2);
86   
87           System.out.println("Total length: " + totalLengthProduct);
88   
89       }
90       private static String firstName(String directoryStyleName) {
91           int firstComma = directoryStyleName.indexOf(",");
92           String firstName = directoryStyleName.substring(firstComma + 2);
93           return firstName;
94   
95       }
96       private static String lastName(String directoryStyleName) {
97           int lastComma = directoryStyleName.indexOf(",");
98           String lastName = directoryStyleName.substring(0, lastComma);
99           return lastName;
100      }
101  }
102