1    /* 
2     * A program to perform some basic operations on a list of Strings using Java streams 
3     */
4    
5    package arraylists;
6    
7    import java.util.ArrayList;
8    import java.util.List;
9    import java.util.stream.Collectors;
10   
11   
12   public class StreamArrayListProcessing {
13   
14       public static void main(String[] args) {
15           //POINT A: Add some strings which represent names to an ArrayList.
16           List<String> names = new ArrayList<>();
17           names.add("Holiday, Billie");
18           names.add("Claudel, Camille");
19           names.add("Picasso, Pablo");
20           names.add("Gallen-Kallela, Akseli");
21           names.add("Zotto, Osvaldo");
22           names.add("Tepfenhart-Yamada, Emily");
23           names.add("Jingleheimer-Schmidt, John Jacob");
24   
25   
26           //POINT B: Use map and the toList collector to create an ArrayList of just the first names of the names ArrayList. Use a for loop to print out the names, separated by spaces.
27   
28           List<String> firstNamesList = names.stream()
29                   .map(n -> firstName(n))
30                   .collect(Collectors.toList());
31   
32           System.out.println("First names: ");
33           for (String firstName : firstNamesList) {
34               System.out.print(firstName + " ");
35           }
36           System.out.println();
37   
38           //POINT C: Use map and the joining collector to create a String of just the first names of the names ArrayLis with each name separated by a comma. Print it.
39           String firstNames = names.stream()
40                   .map(n -> firstName(n))
41                   .collect(Collectors.joining(", "));
42   
43           System.out.println("First names: " + firstNames);
44   
45           //POINT D: By analogy from point C, print a comma-separated list of the last names in the names ArrayList.
46           String lastNames = names.stream()
47                   .map(n -> lastName(n))
48                   .collect(Collectors.joining(", "));
49   
50           System.out.println("Last names: " + lastNames);
51   
52           //POINT E: Print a comma-separated list of all uppercase first names from the list of names in the names ArrayList.
53           String upperCaseFirstNames = names.stream()
54                   .map(n -> firstName(n))
55                   .map(n -> n.toUpperCase())
56                   .collect(Collectors.joining(", "));
57   
58           System.out.println("Uppercase first names: " +upperCaseFirstNames);
59   
60           //POINT F: Print a comma-separated list of all hyphenated last names from the list of names in the names ArrayList.
61           String hyphenatedLastNames = names.stream()
62                   .map(n -> lastName(n))
63                   .filter(n -> n.contains("-"))
64                   .collect(Collectors.joining(", "));
65   
66           System.out.println("Hyphenated last names: " + hyphenatedLastNames);
67   
68           //POINT G: Print the integer value of the total length of all names in the names ArrayList.
69           int totalLength = names.stream()
70                   .map(n -> n.length())
71                   .reduce(0, (n1, n2) -> n1 + n2);
72   
73           System.out.println("Total length: " + totalLength);
74   
75           //POINT H: Print the integer value of the total length of all names in the names ArrayList.
76           int totalLengthOfFirstNames = names.stream()
77                   .map(n -> firstName(n))
78                   .map(n -> n.length())
79                   .reduce(0, (n1, n2) -> n1 + n2);
80   
81           System.out.println("Total first name length: " + totalLengthOfFirstNames);
82   
83           //POINT I: Print the integer value of the product of the length of all first names in the names ArrayList.
84           int totalProductOfLength = names.stream()
85                   .map(n -> n.length())
86                   .reduce(1, (n1, n2) -> n1 * n2);
87   
88           System.out.println("Total product of name length: " + totalProductOfLength);
89   
90       }
91   
92       private static String firstName(String directoryStyleNames) {
93   
94           return directoryStyleNames.substring(directoryStyleNames.indexOf(" ") + 1);
95       }
96   
97       private static String lastName(String directoryStyleName){
98   
99           return directoryStyleName.substring(0,directoryStyleName.indexOf(","));
100      }
101  
102  
103  }