1    package arraylist;
2    
3    import java.util.ArrayList;
4    import java.util.List;
5    import java.util.stream.Collectors;
6    
7    public class StreamArrayListProcessing {
8        public static void main(String[] args){
9    // POINT A: Add some strings which represent names to an ArrayList.
10           List<String> names = new ArrayList<>();
11           names.add("Holiday, Billie");
12           names.add("Claudel, Camille");
13           names.add("Picasso, Pablo");
14           names.add("Gallen-Kallela, Akseli");
15           names.add("Zotto, Osvaldo");
16           names.add("Chen, Jakie");
17           names.add("Khan, Genghis");
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 joining 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   // POINT D: By analogy from point C, print a comma-separated list of the
38   //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 Name: " + lastnames);
43   
44   // POINT E: Print a comma-separated list of all uppercase first names
45   //from the list of names in the names ArrayList.
46           String upperCaseFirstNames = names.stream()
47                   .map(n -> firstName(n))
48                   .map(n -> n.toUpperCase())
49                   .collect(Collectors.joining(", "));
50           System.out.println("Uppercase first names: " + upperCaseFirstNames);
51   
52   // POINT F: Print a comma-separated list of all hyphenated last names
53   //from the list of names in the names ArrayList.
54           String hyphenatedLastNames = names.stream()
55                   .map(n -> lastName(n))
56                   .filter(n -> n.contains("-"))
57                   .collect(Collectors.joining(", "));
58           System.out.println("Hypenated last name " + hyphenatedLastNames);
59   
60   // POINT G: Print the integer value of the total length of all names
61   //in the names ArrayList.
62   
63           int totalLength = names.stream()
64                   .map(n -> n.length())
65                   .reduce(0, (n1, n2) -> n1 + n2);
66   
67           System.out.println("Total length: " + totalLength);
68   // POINT H: Print the integer value of the total length of all
69   //first names in the names ArrayList.
70           int firstNameLength = names.stream()
71                   .map(n -> firstName(n).length())
72                    .reduce(0, (n1, n2) -> n1 + n2);
73   
74           System.out.println("Total First length: " + firstNameLength);
75   
76   // POINT I: Print the integer value of the product of the length of
77   //all first names in the names ArrayList.
78           int ProductNameLength = names.stream()
79                   .map(n -> firstName(n).length())
80                   .reduce(1, (n1, n2) -> n1 * n2);
81   
82           System.out.println(" Product Total length: " + ProductNameLength);
83       }
84       private static String firstName(String directoryStyleName) {
85           int commaPosition = directoryStyleName.indexOf(",");
86           String firstName = directoryStyleName.substring(commaPosition + 1);
87   
88   
89           return firstName;
90       }
91       private static String lastName(String directoryStyleName) {
92           int commaPosition = directoryStyleName.indexOf(",");
93           String lastName = directoryStyleName.substring(0,commaPosition);
94           return lastName;
95       }
96   }
97