1    package arraylistplay;
2    
3    import java.util.ArrayList;
4    import java.util.List;
5    import java.util.stream.Collectors;
6    
7    public class StreamArrayListProcessing {
8    
9        public static void main(String[] args) {
10           //POINT A: Add some strings which represent names to an ArrayList
11           List<String> names = new ArrayList<>();
12           names.add("Holiday, Billie");
13           names.add("Claudel, Camille");
14           names.add("Picasso, Pablo");
15           names.add("Gallen-Kallela, Akseli");
16           names.add("Zotto, Osvaldo");
17   
18           //POINT B: Use map and the toList collector to create an ArrayList of just the
19           //          first names of the names ArrayList. Use a for loop to print
20           //          out the names, separated by spaces
21           List<String> firstNameList = names.stream()
22                   .map(n -> firstName(n))
23                   .collect(Collectors.toList());
24   
25           System.out.println("First names: ");
26           for (String firstName : firstNameList) {
27               System.out.println(firstName + " ");
28           }
29           System.out.println();
30   
31           //POINT C: Use map and the joining collector to create a String of just
32           //          the first names of the ArrayList with each name separated
33           //          by a comma. Print it.
34           String firstNames = names.stream()
35                   .map(n -> firstName(n))
36                   .collect(Collectors.joining(", "));
37   
38           System.out.println("First names: " + firstNames);
39   
40           //POINT D: By analogy from point c, print a comma-separated list of the
41           //          last names in the names ArrayList
42           String lastNames = names.stream()
43                   .map(n -> lastName(n))
44                   .collect(Collectors.joining(", "));
45   
46           System.out.println("Last names: " + lastNames);
47   
48           //POINT E: Print a comma-separated list of all uppercase fist names
49           //          from the list of names in the names ArrayList
50           String upperCaseFirstNames = names.stream()
51                   .map(n -> firstName(n))
52                   .map(n -> n.toUpperCase())
53                   .collect(Collectors.joining(", "));
54   
55           System.out.println("Uppercase first names: " + upperCaseFirstNames);
56   
57   
58           //POINT F: Print a comma-separated list of all hyphenated last names
59           //          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
68           //          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
76           //          first names in the names ArrayList
77           int firstNamesTotalLength = firstNameList.stream()
78                   .map(n->n.length())
79                   .reduce(0 , (n1, n2) -> n1 + n2);
80   
81           System.out.println("First names total length: " + firstNamesTotalLength);
82   
83           //POINT I: Print the integer value of the product of the length of
84           //          all first names in the names ArrayList
85           int firstNamesLength = firstNameList.stream()
86                   .map(n -> n.length())
87                   .reduce(1, (n1, n2) -> n1 * n2);
88           System.out.println("First names product of lengths: " + firstNamesLength);
89       }
90       private static String firstName(String directoryStyleName) {
91           int commaPos = directoryStyleName.indexOf(",");
92           String firstNames = directoryStyleName.substring(commaPos + 1);
93   
94           return firstNames;
95       }
96   
97       private static String lastName(String directoryStyleName) {
98           int commaPos = directoryStyleName.indexOf(",");
99           String lastName = directoryStyleName.substring(0,commaPos);
100  
101          return lastName;
102  
103      }
104  }
105