1    /* 
2     * A program to perform some basic operations on a list of Strings 
3     * using Java streams. 
4     */
5    package arraylistplay;
6    
7    import java.util.ArrayList;
8    import java.util.List;
9    import java.util.stream.Collectors;
10   
11   public class StreamArrayListProcessing {
12       public static void main(String[] arg) {
13   
14           //Point A:
15           List<String> names = new ArrayList<>();
16           names.add("Holiday, Billie");
17           names.add("Squarepants, Spongebob");
18           names.add("Brady, Tom");
19           names.add("Saget, Bob");
20           names.add("Joe, Billy-Bob");
21           names.add("Green, Nathan");
22   
23   
24           //Point B:
25           List<String> firstNamesList = names.stream()
26                   .map(n -> firstName(n))
27                   .collect(Collectors.toList());
28           System.out.println("First names: ");
29           for (String firstName : firstNamesList){
30               System.out.println(firstName + " ");
31           }System.out.println();
32   
33           //Point C:
34           String firstNames = names.stream()
35                   .map(n -> firstName(n))
36                   .collect(Collectors.joining(", "));
37           System.out.println("First names: " + firstNames);
38           System.out.println();
39   
40           //Point D:
41           List<String> lastNamesList = names.stream()
42                   .map(n -> lastName(n))
43                   .collect(Collectors.toList());
44           System.out.println("Last names: ");
45           for (String lastName : lastNamesList){
46               System.out.println(lastName + " ");
47           }System.out.println();
48   
49           String lastNames = names.stream()
50                   .map(n -> lastName(n))
51                   .collect(Collectors.joining(", "));
52           System.out.println("Last names: " + lastNames);
53   
54           //Point E:
55           String upperCaseFirstNames = names.stream()
56                   .map(n -> firstName(n))
57                   .map(n -> n.toUpperCase())
58                   .collect(Collectors.joining(", "));
59           System.out.println("Uppercase first names: " + upperCaseFirstNames);
60   
61           //Point F:
62           String hyphenatedLastNames = names.stream()
63                   .map(n -> lastName(n))
64                   .filter(n -> n.contains("-"))
65                   .collect(Collectors.joining(", "));
66           System.out.println("hyphenateds names: " + hyphenatedLastNames);
67   
68           //Point G:
69           int totalLength = names.stream()
70                   .map(n -> n.length())
71                   .reduce(0, (n1, n2) -> n1 + n2);
72           System.out.println("Total length: " + totalLength);
73   
74           //Point H:
75           int totalfirstLength = names.stream()
76                   .map(n -> n.length())
77                   .reduce(0, (n1, n2) -> n1 + n2);
78           System.out.println("first name Total length: " + totalfirstLength);
79   
80           //Point I:
81           double totalProduct= names.stream()
82                   .map(n-> n.length())
83                   .reduce(1,(n1,n2)-> n1 * n2);
84           System.out.println("Total Product:"+ totalProduct);
85       }
86   
87       private static String firstName(String directoryStyleName) {
88           int commaPosition = directoryStyleName.indexOf(",");
89           return directoryStyleName.substring(commaPosition + 2);
90       }
91       private static String lastName(String directoryStyleName) {
92           int commaPosition = directoryStyleName.indexOf(",");
93           return directoryStyleName.substring(0, commaPosition);
94       }
95   }