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SteamArrayListProcessing.java
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1 /*
2 * A program to perform some basic operations on a list of String names
3 */
4 package arraylist;
5
6 import java.util.ArrayList;
7 import java.util.List;
8 import java.util.stream.Collectors;
9
10 public class SteamArrayListProcessing {
11
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("Fisher, Raymond");
21 names.add("Brown-Johnson, Bob");
22
23 //POINT B: Use map and the toList collector to create an ArrayList of just
24 // the first names of the names ArrayList. Use a for loop to print
25 // out the names, separated by spaces.
26 List<String> firstNamesList = names.stream()
27 .map(n -> firstName(n))
28 .collect(Collectors.toList());
29 System.out.print("First names: ");
30 for (String firstName : firstNamesList) {
31 System.out.print(firstName + " ");
32 }
33 System.out.println();
34
35 //POINT C: Use map and the joining collector to create a String of just
36 // the first names of the names ArrayList with each name separated
37 // by a comma. Print it.
38
39 String firstNames = names.stream()
40 .map(n -> firstName(n))
41 .collect(Collectors.joining(", "));
42
43 System.out.println("First names: " + firstNames);
44
45
46 //POINT D: By analogy from points B and C, print a comma-separated
47 //list of the last names in the names ArrayList
48
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 System.out.println("Uppercase first names: " + upperCaseFirstNames);
62
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 System.out.println("Hyphenated last names: " + hyphenatedLastNames);
71
72
73 //POINT G: Print the integer values of the total length of all names in the names ArrayList
74 int totalLength = names.stream()
75 .map(n -> n.length())
76 .reduce(0, (n1, n2) -> n1 + n2);
77 System.out.println("Total Length: " + totalLength);
78
79
80 //POINT H: Print the integer value of the total length of all
81 //first names in the names ArrayList
82 int fNameTotalLength = names.stream()
83 .map(n -> firstName(n))
84 .map(n -> n.length())
85 .reduce(0, (n1, n2) -> n1 + n2);
86 System.out.println("Total First Name Length: " + fNameTotalLength);
87
88 //POINT I: Print the integer value of the product of the length of
89 //all first names in the name ArrayList
90 int productLength = names.stream()
91 .map(n -> firstName(n))
92 .map(n -> n.length())
93 .reduce(1, (n1, n2) -> n1 * n2);
94 System.out.println("Product of first names length: " + productLength);
95
96
97 }
98
99 private static String firstName(String directoryStyleName) {
100 int positionOfComma = directoryStyleName.indexOf(",");
101 String firstName = directoryStyleName.substring(positionOfComma + 2); ///Without the +2 the comma shows in the output
102 return firstName;
103 }
104
105
106
107 private static String lastName(String directoryStyleName) {
108 int positionOfComma = directoryStyleName.indexOf(",");
109 String lastName = directoryStyleName.substring(0, positionOfComma);
110 return lastName;
111 }
112
113
114
115
116 }
117
118