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