1    package arraylistplay;
2    
3    import java.util.List;
4    import java.util.ArrayList;
5    import java.util.stream.Collectors;
6    
7    public class StreamArrayListProcessing {
8    
9        public static void main(String[] args) {
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("Jeter, Derek");
17           names.add("Thompson, Nathan");
18   
19           // Point B: Use map and the toList collector to create an ArrayList of just
20           // the first names of the names ArrayList. Use a for loop to print out the
21           // names, separated by spaces.
22   
23           List<String> firstNamesList = names.stream()
24                   .map(n -> firstName(n))
25                   .collect(Collectors.toList());
26           System.out.print("First Names: ");
27           for ( String firstName : firstNamesList ) {
28               System.out.print(firstName + " ");
29           }
30           System.out.println();
31           System.out.println();
32   
33           // Point C : Use map and the joining collector to create a String of just the first
34           // names of the names ArrayList with each name separated by a comma. Print it.
35   
36           String firstNames = names.stream()
37                   .map( n -> firstName(n))
38                   .collect(Collectors.joining(", "));
39           System.out.println("First Names: " + firstNames);
40           System.out.println();
41   
42           // Point D : By analogy from Point C, print a comma-separated list of the last names
43           // in the names ArrayList.
44   
45           String lastNames = names.stream()
46                   .map(n -> lastName(n))
47                   .collect(Collectors.joining(", "));
48           System.out.println("Last Names: " + lastNames);
49           System.out.println();
50   
51           // Point E : Print a comma-separated list of all uppercase first names from the list
52           // of names in the names ArrayList.
53   
54           String upperCaseFirstNames = names.stream()
55                   .map(n -> firstName(n))
56                   .map(n -> n.toUpperCase())
57                   .collect(Collectors.joining(", "));
58           System.out.println("Uppercase First Names: " + upperCaseFirstNames);
59           System.out.println();
60   
61           // Point F : Print a comma-separated list of all hyphenated last names from the list
62           // of names in the names ArrayList.
63   
64           String hyphenatedLastNames = names.stream()
65                   .map(n -> lastName(n))
66                   .filter(n -> n.contains("-"))
67                   .collect(Collectors.joining(","));
68           System.out.println("Hyphenated Last Names: " + hyphenatedLastNames);
69           System.out.println();
70   
71           // Point G : Print the integer value of the total length of all names in the names
72           // ArrayList
73   
74           int totalLength = names.stream()
75                   .map(n -> n.length())
76                   .reduce(0,(n1,n2) -> n1 + n2);
77           System.out.println("Total Names Length: " + totalLength);
78           System.out.println();
79   
80           // Point H : Print the integer value of the total length of all the first names in the
81           // names ArrayList.
82   
83           int totalFirstLength = firstNamesList.stream()
84                   .map(n -> n.length())
85                   .reduce(0,(n1,n2) -> n1 + n2);
86           System.out.println("Total First Names Length: " + totalFirstLength);
87           System.out.println();
88   
89           // Point I : Print the integer value of the total product of all the names in the names
90           // ArrayList.
91   
92           double totalProduct = names.stream()
93                   .map(n -> n.length())
94                   .reduce(1,(n1,n2) -> n1 * n2);
95           System.out.println("Total Product: " + totalProduct);
96       }
97   
98       private static String firstName(String directoryStyleName) {
99           int commaPosition = directoryStyleName.indexOf(",");
100          String firstName = directoryStyleName.substring(commaPosition + 1);
101          return firstName;
102      }
103  
104      private static String lastName(String directoryStyleName) {
105          int commaPosition = directoryStyleName.indexOf(",");
106          String lastName = directoryStyleName.substring(0, commaPosition);
107          return lastName;
108      }
109  }