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("Newell, Rachel");
23           names.add("Washington, George");
24   
25           //POINT B: Use map and the toList collector to create an ArrayList of just
26           // the first names of the names ArrayList. Use a for loop to print
27           // out the names, separated by spaces.
28           List<String> firstNamesList = names.stream()
29                   .map(n -> firstName(n))
30                   .collect(Collectors.toList());
31   
32           System.out.print("First names: ");
33           for (String firstName : firstNamesList) {
34               System.out.print(firstName + " ");
35           }
36           System.out.println();
37   
38           //POINT C: Use map and the joining collector to create a String of just
39           // the first names of the names ArrayList with each name separated
40           // by a comma. Print it.
41           String firstNames = names.stream()
42                   .map(n -> firstName(n))
43                   .collect(Collectors.joining(", "));
44   
45           System.out.println("First names: " + firstNames);
46   
47           //POINT D: By analogy from point C, print a comma-separated list of the
48           // last names in the names ArrayList.
49           String lastNames = names.stream()
50                   .map(n -> lastName(n))
51                   .collect(Collectors.joining(", "));
52   
53           System.out.println("Last names: " + lastNames);
54   
55           //POINT E: Print a comma-separated list of all uppercase first names
56           // from the list of names in the names ArrayList.
57           String upperCaseFirstNames = names.stream()
58                   .map(n -> firstName(n))
59                   .map(n -> n.toUpperCase())
60                   .collect(Collectors.joining(", "));
61   
62           System.out.println("Uppercase first names: " + upperCaseFirstNames);
63   
64           //POINT F: Print a comma-separated list of all hyphenated last names
65           // from the list of names in the names ArrayList.
66           String hyphenatedLastNames = names.stream()
67                   .map(n -> lastName(n))
68                   .filter(n -> n.contains("-"))
69                   .collect(Collectors.joining(", "));
70   
71           System.out.println("Hyphenated last names: " + hyphenatedLastNames);
72   
73           //POINT G: Print the integer value of the total length of all names
74           // in the names ArrayList.
75           int totalLength = names.stream()
76                   .map(n -> n.length())
77                   .reduce(0, (n1, n2) -> n1 + n2);
78   
79           System.out.println("Total length: " + totalLength);
80   
81           //POINT H:  Print the integer value of the total length of all
82           // first names in the names ArrayList.
83           int totalFirstNameLength = names.stream()
84                   .map(n -> firstName(n).length())
85                   .reduce(0, (n1, n2) -> n1 + n2);
86   
87           System.out.println("Total First Name Length: " + totalFirstNameLength);
88   
89           //POINT I: Print the integer value of the product of the length of  
90           // all first names in the names ArrayList.
91           int totalFirstNameProduct = names.stream()
92                   .map(n -> firstName(n).length())
93                   .reduce(1, (n1, n2) -> n1 * n2);
94   
95           System.out.println("Total Product: " + totalFirstNameProduct);
96       }
97   
98       private static String firstName(String directoryStyleName) {
99           int spaceLocation = directoryStyleName.indexOf(" ");
100          return directoryStyleName.substring(spaceLocation + 1);
101      }
102  
103      private static String lastName(String directoryStyleName) {
104          int commaLocation = directoryStyleName.indexOf(",");
105          return directoryStyleName.substring(0,commaLocation);
106      }
107  
108  
109  
110  }
111