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