1    /* 
2    A program to preform some basic operations on a list of strings 
3    using java Streams 
4     */
5    
6    package arraylists;
7    
8    import java.awt.*;
9    import java.util.ArrayList;
10   import java.util.List;
11   import java.util.stream.Collector;
12   import java.util.stream.Collectors;
13   
14   public class StreamArrayListProcessing {
15   
16       public static void main(String[] args) {
17           //point a: add some strings which represent names to an arraylist
18           List<String> names = new ArrayList<>();
19           names.add("Holiday, Billie");
20           names.add("Claudel, Camille");
21           names.add("Picasso, Pablo");
22           names.add("Gallen-Kallela, Akseli");
23           names.add("Zotto, Osvaldo");
24           names.add("Lovell, Owen");
25           names.add("Gomez, Selena");
26           names.add("Eilish, Billie");
27   
28           //point b: use map and the toList collector to create an ArrayList of just
29           // the first names of the names ArrayList. use a for loop to print
30           // out the names, seperated by spaaces.
31   
32           List<String> firstNamesList = names.stream()
33                   .map(n -> firstName(n))
34                   .collect(Collectors.toList());
35   
36           System.out.print("First Names: ");
37           for (String firstName : firstNamesList){
38               System.out.print(firstName + " ");
39           }
40           System.out.println();
41   
42           //poijnt c: use map and joining collector to create a string of just
43           // the first names of the names Array List with each name seperated by a]
44           // comma. print it
45           String firstNames = names.stream()
46                   .map(n -> firstName(n))
47                   .collect(Collectors.joining(", "));
48   
49           System.out.println("First names: " + firstNames);
50   
51           //point d: by analogy from point c print a comma seperated list
52           // of the last names in the ArrayList
53           String lastNames = names.stream()
54                   .map(n -> lastName(n))
55                   .collect(Collectors.joining(", "));
56   
57           System.out.println("Last Names: " + lastNames);
58   
59           //point E: priont a comma-seperated list of all the uppercasre last names fomr the list of names in the n
60           //names arraylist
61   
62           String upperCaseFirstNames = names.stream()
63                   .map( n -> firstName(n))
64                   .map(n -> n.toUpperCase())
65                   .collect(Collectors.joining(", "));
66   
67           System.out.println("Uppercase first names: " + upperCaseFirstNames);
68   
69           //point f: print  a comma-seperated list of all the hyphenated last names fomr the list of names in the n
70           //        //names arraylist
71   
72           String hyphenatedLastNames = names.stream()
73                   .map(n -> lastName(n))
74                   .filter(n -> n.contains("-"))
75                   .collect(Collectors.joining(", "));
76   
77           System.out.println("Hyphenated last names: " + hyphenatedLastNames);
78   
79           //point g: priont the integer value of the total length of all names in the array list
80           int totalLength = names.stream()
81                   .map(n -> n.length())
82                   .reduce(0, (n1, n2) -> n1 + n2);
83   
84           System.out.println("Total length: " + totalLength);
85   
86   
87           //point h: priont the integer value of the total length of all first
88           // names in the array list
89           int firstLength = names.stream()
90                   .map(n -> firstName(n))
91                   .map(n -> n.length())
92                   .reduce(0, (n1,n2) -> n1 +n2);
93           System.out.println("First name total length: " + firstLength);
94   
95           //point i: priont the integer value of the product of length
96           //all first names in arraylist
97           int totalProduct = names.stream()
98                   .map(n -> firstName(n))
99                   .map(n -> n.length())
100                  .reduce(1, (n1,n2) -> n1 * n2);
101  
102          System.out.println("Product of lengths: " + totalProduct);
103  
104  
105      }
106      private static String firstName(String directoryStyleName) {
107          int positionOfComma = directoryStyleName.indexOf(",");
108          String firstName = directoryStyleName.substring(positionOfComma + 2);
109          return firstName;
110      }
111      private static String lastName(String directoryStyleName) {
112          int positionOfComma = directoryStyleName.indexOf(",");
113          String lastName = directoryStyleName.substring(0,positionOfComma);
114          return lastName;
115      }
116  
117  }
118