1    /* 
2     * Program featuring an array to store and interactively manipulate a list of numbers. 
3     */
4    
5    
6    package arrayPlay;
7    
8    import java.io.File;
9    import java.io.FileNotFoundException;
10   import java.util.Scanner;
11   
12   public class WordList {
13       //Variables local to the class, and hence global to the methods
14       private static final int LIMIT= 1000;
15       private static String[] Words = new String[LIMIT];
16       private static int numberOfWords = 0;
17       private static Scanner commandReader= new Scanner(System.in);
18   
19       public static void main(String[]args) {
20           try {
21   
22               //Establish the array of numbers
23               readWords();
24               //Check the data
25               System.out.println("\nThe original list of numbers...");
26               displayNumbers();
27               //Enter the interpreter
28               interpreter();
29           } catch (FileNotFoundException ex) {
30               System.out.println("The file was not found. Please think again.");
31               System.exit(-1);
32   
33           }
34       }
35       private static void readWords() throws FileNotFoundException {
36           Scanner scanner = establishScanner("WordSet.txt");
37           while (scanner.hasNext()) {
38               Words[numberOfWords] = scanner.next();
39               numberOfWords = numberOfWords + 1;
40           }
41       }
42       private static Scanner establishScanner (String fn) throws FileNotFoundException {
43           String separator = File.separator;
44           String homeDirectory = System.getProperty("user.home");
45           String path = homeDirectory + separator + "public_html" + separator + "data" + separator;
46           String fullFileName = path + fn;
47           return new Scanner(new File(fullFileName));
48       }
49       private static void interpreter () {
50           System.out.print(">>>");
51           String command = commandReader.next();
52           if (command.equalsIgnoreCase("DISPLAY")) {
53               interpreterDisplayCommand();
54           } else if (command.equalsIgnoreCase("PRINT")) {
55               interpretPrintCommand();
56           } else if (command.equalsIgnoreCase("SWAP")) {
57               interpretSwapCommand();
58           } else if (command.equalsIgnoreCase("ADD")) {
59               interpretAddCommand();
60           } else if (command.equalsIgnoreCase("HELP")) {
61               interpretHelpCommand();
62           } else if (command.equalsIgnoreCase("EXIT")) {
63               System.exit(0);
64           } else {
65               System.out.println("### Unrecognizable command:" + command);
66           }
67           interpreter();
68       }
69   
70       private static void interpreterDisplayCommand() {
71           displayNumbers();
72       }
73   
74       private static void displayNumbers() {
75           for (int x = 0; x< numberOfWords; x=x+1){
76               System.out.println(Words[x]);
77           }
78       }
79   
80       private static void interpretPrintCommand() {
81           String operand= commandReader.next();
82           if (operand.equalsIgnoreCase("FIRST")) {
83               System.out.println(Words[0]);
84           }else if (operand.equalsIgnoreCase("LAST")) {
85               System.out.println(Words[numberOfWords - 1]);
86           }else {
87               int index= Integer.valueOf(operand);
88               System.out.println(Words[index-1]);
89           }
90       }
91       private static void interpretSwapCommand() {
92           int position1= commandReader.nextInt();
93           int position2= commandReader.nextInt();
94           String temp= Words[position1-1];
95           Words[position1-1]= Words[position2-1];
96           Words[position2-1]=temp;
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("ADD  - add a number to the list(FIRST; LAST)");
103          System.out.println("EXIT - terminate execution of the program");
104      }
105      private static void interpretAddCommand() {
106          String position= commandReader.next();
107          if (position.equalsIgnoreCase("LAST")) {
108              addLast();
109          }else if (position.equalsIgnoreCase("FIRST")) {
110              addFIRST();
111          }else {
112              System.out.println("### invalid operand for add command");
113          }
114          numberOfWords = numberOfWords +1;
115      }
116      private static void addLast() {
117          Words[numberOfWords]= commandReader.next();
118      }
119      private static void addFIRST(){
120          for (int x = numberOfWords; x>0; x=x-1){
121              Words[x]= Words[x-1];
122          }
123          Words[0]= commandReader.next();
124      }
125  
126  }
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