1    /* 
2     *Program featuring an array to store and interactively manipulate a list of words. 
3     */
4    package arrayplay;
5    
6    import java.io.File;
7    import java.io.FileNotFoundException;
8    import java.util.ArrayList;
9    import java.util.Scanner;
10   
11   public class WordList {
12       //VARIABLES LOCAL TO THE CLASS, AND HENCE GLOBAL TO THE METHODS
13      // private static final int LIMIT = 1000;
14       private static ArrayList <String> words = new ArrayList<>();
15       private static Scanner commandReader = new Scanner(System.in);
16   
17   
18       public static void main(String[] args) {
19           try {
20               //ESTABLISH THE ARRAY OF WORDS
21               readWords();
22               //CHECK THE DATA
23               //System.out.println("nThe original list of numbers...");
24               //displayNumber();
25               //ENTER THE INTERPRETER
26               interpreter();
27           } catch (FileNotFoundException ex) {
28               System.out.println("The file was not found. please think again.");
29               System.exit(-1);
30           }
31       }
32   
33       //Assuming that the data file will be found in the public_html/data
34       //subdirectory of the user's home directory.
35       private static Scanner establishScanner(String fn) throws FileNotFoundException {
36           String separator = File.separator;
37           String homeDirectory = System.getProperty("user.home");
38           String path = homeDirectory + separator + "public_html" + separator + "data" + separator;
39           String fullFileName = path + fn;
40           return new Scanner(new File(fullFileName));
41       }
42   
43       private static void readWords() throws FileNotFoundException {
44           Scanner scanner = establishScanner("WordSet.txt");
45           while (scanner.hasNext()) {
46               words.add(scanner.next());
47           }
48       }
49   
50       private static void displayWords() {
51           for (int x = 0; x < words.size(); x = x + 1) {
52               System.out.println(words.get(x));
53           }
54       }
55   
56       private static void interpreter() {
57           System.out.println(">>> ");
58           String command = commandReader.next();
59           if (command.equalsIgnoreCase("DISPLAY")) {
60               interpreterDisplayCommand();
61           } else if (command.equalsIgnoreCase("PRINT")) {
62               interpreterPrintCommand();
63           }else if (command.equalsIgnoreCase("SWAP")) {
64               interpreterSwapCommand();
65           }else if (command.equalsIgnoreCase("ADD")) {
66               interpreterAddCommand();
67           }else if (command.equalsIgnoreCase("HELP")) {
68               interpreterHelpCommand();
69           }else if (command.equalsIgnoreCase("EXIT")) {
70               System.exit(0);
71           }else {
72               System.out.println("### Unrecognized command: " + command);
73           }
74           interpreter();
75       }
76   
77       private static void interpreterDisplayCommand() {
78   
79           displayWords();
80       }
81   
82       private static void interpreterPrintCommand() {
83           String operand = commandReader.next();
84           if (operand.equalsIgnoreCase("FIRST")) {
85               System.out.println(words.get(0));
86           }else if (operand.equalsIgnoreCase("LAST")) {
87               System.out.println(words.get(words.size() - 1));
88           }else {
89               int index = Integer.valueOf(operand);
90               System.out.println(words.get(index - 1));
91           }
92       }
93   
94       private static void interpreterHelpCommand() {
95           System.out.println("HELP - display a menu of commands");
96           System.out.println("DISPLAY - display the list of numbers");
97           System.out.println("PRINT - print a number (FIRST;LAST;nth");
98           System.out.println("SWAP - exchange two elements (nth;mth)");
99           System.out.println("ADD - add a number to the list (FIRST;LAST)");
100          System.out.println("EXIT - terminate execution of the program ");
101      }
102  
103      private static void interpreterSwapCommand() {
104          int position1 = commandReader.nextInt();
105          int position2 = commandReader.nextInt();
106          String temp = words.get(position1 - 1);
107          words.set(position1 - 1, words.get(position2 - 1));
108          words.set(position2 -1, temp);
109      }
110  
111      private static void interpreterAddCommand() {
112          String position = commandReader.next();
113          if (position.equalsIgnoreCase("LAST")) {
114              addLast();
115          } else if (position.equalsIgnoreCase("FIRST")) {
116              addFirst();
117          } else {
118              System.out.println("### invalid operand for add command");
119          }
120  
121      }
122      private static void addLast() {
123          words.add(commandReader.next());
124  
125      }
126      private static void addFirst() {
127          for (int x = words.size(); x > 0; x = x - 1) {
128              words.set(x, words.get(x - 1));
129          }
130          words.add(0, commandReader.next());
131  
132  
133      }
134  }
135  
136  
137  
138