1    package arrayplay;
2    
3    import java.io.File;
4    import java.io.FileNotFoundException;
5    import java.util.Scanner;
6    
7    public class WordList {
8    
9    
10   
11   
12   
13   
14   
15       private static final int LIMIT = 1000;
16       private static String[] words = new String[LIMIT];
17       private static int numberOfWords = 0;
18       private static Scanner commandReader = new Scanner(System.in);
19   
20   
21           public static void main(String[] args) {
22               try {
23                   // ESTABLISH THE ARRAY OF NUMBERS
24                   readNumbers();
25   
26                   // CHECK THE DATA
27                   System.out.println("nThe original list of numbers ...");
28                   displayNumbers();
29                   // ENTER THE INTERPRETER
30                   interpreter();
31               } catch (FileNotFoundException ex) {
32                   System.out.println("The file was not found. Please think again.");
33                   System.exit(-1);
34               }
35           }
36       // Assuming that the data file will be found in the public_html/data
37       // subdirectory of the user’s home directory.
38       private static Scanner establishScanner(String fn) throws FileNotFoundException {
39           String separator = File.separator;
40           String homeDirectory = System.getProperty("user.home");
41           String path = homeDirectory + separator + "public_html" + separator + "data" + separator + "WordSet.txt";
42           String fullFileName = path ;
43           System.out.println(fullFileName);
44           return new Scanner(new File(fullFileName));
45       }
46   
47       private static void readNumbers() throws FileNotFoundException {
48           Scanner scanner = establishScanner("NumberSet.txt");
49           while (scanner.hasNext()) {
50               words[numberOfWords] = scanner.next();
51               numberOfWords = numberOfWords + 1;
52           }
53       }
54   
55       private static void displayNumbers() {
56           for (int x = 0; x < numberOfWords; x = x + 1) {
57               System.out.println(words[x]);
58           }
59       }
60   
61       private static void interpreter() {
62           System.out.print(">>> ");
63           String command = commandReader.next();
64           if (command.equalsIgnoreCase("DISPLAY")) {
65               interpreterDisplayCommand();
66           } else if (command.equalsIgnoreCase("PRINT")) {
67               interpretPrintCommand();
68           } else if (command.equalsIgnoreCase("SWAP")) {
69               interpretSwapCommand();
70           } else if (command.equalsIgnoreCase("ADD")) {
71               interpretAddCommand();
72           } else if (command.equalsIgnoreCase("HELP")) {
73               interpretHelpCommand();
74           } else if (command.equalsIgnoreCase("EXIT")) {
75               System.exit(0);
76           } else {
77               System.out.println("### Unrecognizable command: " + command);
78           }
79           interpreter();
80       }
81   
82       private static void interpreterDisplayCommand() {
83           displayNumbers();
84       }
85   
86       private static void interpretPrintCommand() {
87           String operand = commandReader.next();
88           if (operand.equalsIgnoreCase("FIRST")) {
89               System.out.println(words[0]);
90           } else if (operand.equalsIgnoreCase("LAST")) {
91               System.out.println(words[numberOfWords - 1]);
92           } else {
93               int index = Integer.valueOf(operand);
94               System.out.println(words[index - 1]);
95           }
96       }
97   
98       private static void interpretHelpCommand() {
99           System.out.println("HELP - display a menu of commands");
100          System.out.println("DISPLAY - display the list of numbers");
101          System.out.println("PRINT - print a number (FIRST;LAST;nth)");
102          System.out.println("SWAP - exchange two elements (nth;mth)");
103          System.out.println("ADD - add a number to the list (FIRST;LAST)");
104          System.out.println("EXIT - terminate execution of the program");
105      }
106  
107      private static void interpretSwapCommand() {
108          int position1 = commandReader.nextInt();
109          int position2 = commandReader.nextInt();
110          String temp = words[position1 - 1];
111          words[position1 - 1] = words[position2 - 1];
112          words[position2 - 1] = temp;
113      }
114  
115  
116      private static void interpretAddCommand() {
117          String position = commandReader.next();
118          if (position.equalsIgnoreCase("LAST")) {
119              addLast();
120          } else if (position.equalsIgnoreCase("FIRST")) {
121              addFirst();
122          } else {
123              System.out.println("### invalid operand for add command");
124          }
125          numberOfWords = numberOfWords + 1;
126      }
127  
128      private static void addLast() {
129          words[numberOfWords] = String.valueOf(commandReader.next());
130      }
131  
132      private static void addFirst() {
133          for (int x = numberOfWords; x > 0; x = x - 1) {
134              words[x] = words[x - 1];
135          }
136          words[0] = String.valueOf(commandReader.next());
137      }
138  
139  
140  
141  
142  
143  
144  }
145