1    /* 
2    *A program to perform some basic operations on a list of Strings 
3    * using Java streams. 
4     */
5    package arraylistplay;
6    
7    import java.util.ArrayList;
8    import java.util.List;
9    import java.util.stream.Collectors;
10   
11   public class StreamArrayListProcessing {
12       public static void main(String[] args) {
13           //POINT A: Add some strings which represent names to an ArrayList.
14           List<String> names = new ArrayList<>();
15           names.add("Holiday, Billie");
16           names.add("Claudel, Camille");
17           names.add("Picasso, Pablo");
18           names.add("Gallen-Kallela, Akseli");
19           names.add("Zotto, Osvaldo");
20           names.add("Eilish, Billie");
21           names.add("Reynolds, Dan");
22           names.add("Sermon, Wayne");
23   
24           //POINT B: Use map and the toList collector to create an ArrayList of just
25           //the first names of the names ArrayList. Use a for loop to print
26           //out the names, separated by spaces.
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: Use map and the joining collector to create a String of just
38           //the first names of the names ArrayList with each name separated
39           //by a comma. Print it.
40           String firstNames = names.stream()
41                   .map(n -> firstName(n))
42                   .collect(Collectors.joining(", "));
43           System.out.println("First names: " + firstNames);
44   
45           //POINT D: By analogy from point C, print a comma-separated list of the
46           //last names in the names ArrayList.
47           String lastNames = names.stream()
48                   .map(n -> lastName(n))
49                   .collect(Collectors.joining(", "));
50           System.out.println("Last name: " + lastNames);
51   
52           //POINT E: Print a comma-separated list of all uppercase first names
53           //from the list of names in the names ArrayList.
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   
60           //POINT F: Print a comma-separated list of all uppercase first names
61           //from the list of names in the names ArrayList.
62           String hyphenatedLastNames = names.stream()
63                   .map(n -> lastName(n))
64                   .filter(n -> n.contains("-"))
65                   .collect(Collectors.joining(","));
66           System.out.println("Hyphenated last names: " + hyphenatedLastNames);
67   
68           //POINT G: Print the integer value of the total length of all
69           //names in the names ArrayList.
70           int totalLength = names.stream()
71                   .map(n -> n.length())
72                   .reduce(0,(n1 , n2) -> n1 + n2);
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 totalFirstLength = names.stream()
78                   .map(n -> firstName(n).length())
79                   .reduce(0,(n1 , n2) -> n1 + n2);
80           System.out.println("Total first name length: " + totalFirstLength);
81   
82           //POINT I: Print the integer value of the product of the length of
83           //all first names in the names ArrayList.
84           int totalProductLength = names.stream()
85                   .map(n -> n.length())
86                   .reduce(1, (n1 , n2) -> n1 * n2);
87           System.out.println("Total Product length: " + totalProductLength);
88       }
89   
90       private static String firstName(String directoryStyleName) {
91           int dsnCommaPosition = directoryStyleName.indexOf(",");
92           String firstName = directoryStyleName.substring(dsnCommaPosition + 2);
93           return firstName;
94       }
95   
96       private static String lastName(String directoryStyleName) {
97           int dsnCommaPosition = directoryStyleName.indexOf(",");
98           String lastname = directoryStyleName.substring(0, dsnCommaPosition);
99           return lastname;
100      }
101  
102      public static List<String> upperCaseNames(List<String> names) {
103          List<String> uppercases = new ArrayList<>();
104          for (String name : names) {
105              uppercases.add(name.toUpperCase());
106          }
107          return uppercases;
108      }
109  
110      public static List<String> hyphenatedNames(List<String> names) {
111          List<String> hyphenateds = new ArrayList<>();
112          for (String name : names) {
113              if (name.contains("-")) {
114                  hyphenateds.add(name);
115              }
116          }
117          return hyphenateds;
118      }
119  
120      public static int totalProductNameLength(List<String> names) {
121          int totalProductLength = 1;
122          for (String name : names) {
123              totalProductLength = totalProductLength * name.length();
124          }
125          return totalProductLength;
126      }
127  
128  
129  }
130