1    /* 
2     *A program to perform some basic operations on a list of Strings 
3     * using java Streams 
4     */
5    
6    package arraylists;
7    
8    import java.util.ArrayList;
9    import java.util.List;
10   import java.util.stream.Collectors;
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("Dogg, Snoop");
23           names.add("E, Big");
24   
25           //POINT B: Use map and the toList collector to create an ArrayList
26           // of just the first names of the names ArrayList
27           List<String> firstNamesList = names.stream()
28                   .map(n -> firstName(n))
29                   .collect(Collectors.toList());
30   
31           System.out.print("First Names: ");
32           for (String firstName : firstNamesList){
33               System.out.print(firstName + " ");
34           }
35           System.out.println();
36   
37           //POINT C:
38           String firstNames = names.stream()
39                   .map(n -> firstName(n))
40                   .collect(Collectors.joining(", "));
41           System.out.println("First Names: " + firstNames);
42   
43           //POINT D:
44           String lastNames = names.stream()
45                   .map(n -> lastName(n))
46                   .collect(Collectors.joining(", "));
47           System.out.println("Last Names: " + lastNames);
48   
49           //POINT E:
50           String uppercaseFirstNames = names.stream()
51                   .map(n -> firstName(n))
52                   .map(n -> n.toUpperCase())
53                   .collect(Collectors.joining(", "));
54           System.out.println("Uppercase First Names: " + uppercaseFirstNames);
55           //POINT F:
56           String hyphenatedLastNames = names.stream()
57                   .map(n -> lastName(n))
58                   .filter(n -> n.contains("-"))
59                   .collect(Collectors.joining(", "));
60           //POINT G:
61           int totalLength = names.stream()
62                   .map(n -> n.length())
63                   .reduce(0,(n1, n2) -> n1 + n2);
64           System.out.println("Total Length: " + totalLength);
65   
66           //POINT H:
67           int firstNameLength = names.stream()
68                   .map(n -> firstName(n))
69                   .map(n -> n.length())
70                   .reduce(0,(n1, n2)-> n1 + n2);
71           System.out.println("First Name Length: " + firstNameLength);
72           //POINT I:
73           int productNameLength = names.stream()
74                   .map(n -> n.length())
75                   .reduce(1,(n1, n2) -> n1 * n2);
76           System.out.println("Product of Names: " + productNameLength);
77       }
78   
79       private static String firstName(String name) {
80           int first = name.indexOf(",");
81           String f = name.substring(first + 2);
82           return f;
83       }
84   
85       private static String lastName(String name) {
86           int last = name.indexOf(",");
87           name = name.substring(0, last);
88           return name;
89       }
90   }
91