1 /*
  2  * Program featuring an array to store and interactively manipulate a list
  3  * of numbers.
  4  */
  5 package arraylistplay;
  6 
  7 import java.io.File;
  8 import java.io.FileNotFoundException;
  9 import java.util.ArrayList;
 10 import java.util.Scanner;
 11 
 12 /**
 13  *
 14  * @author evankemp
 15  */
 16 public class WordsList {
 17 
 18     // VARIABLES LOCAL TO THE CLASS< AND HENCE GLOBAL TO THE METHODS
 19     private static int LIMIT = 1000;
 20     private static ArrayList<String> words = new ArrayList<>(LIMIT);
 21     private static int numberOfWords = 0;
 22     private static Scanner commandReader = new Scanner(System.in);
 23 
 24     /**
 25      * @param args the command line arguments
 26      */
 27     public static void main(String[] args) {
 28         try {
 29             //ESTABLISH THE ARRAY OF NUMBERS
 30             readWords();
 31             //CHECK THE DATA
 32             //System.out.println("\nThe original list of numbers ...");
 33             //displayNumbers();
 34             //ENTER THE INTERPRETER
 35             interpreter();
 36         } catch (FileNotFoundException ex) {
 37             System.out.println("The file was not found. Please think again.");
 38             System.exit(-1);
 39         }
 40     }
 41 
 42     //Assuming that the data file will be found in the CS1Files/data
 43     //subdirectory of the user's home director.
 44     private static Scanner establishScanner(String fn) throws FileNotFoundException {
 45         String separator = System.getProperty("file.separator");
 46         String homeDirectory = System.getProperty("user.home");
 47         String path = homeDirectory + separator + "CS1Files" + separator + "data" + separator;
 48         String fullFileName = path + fn;
 49         return new Scanner(new File(fullFileName));
 50     }
 51 
 52     private static void readWords() throws FileNotFoundException {
 53         Scanner scanner = establishScanner("WordSet.text");
 54         while (scanner.hasNext()) {
 55             String word = scanner.next();
 56             words.add(word);
 57             numberOfWords = numberOfWords + 1;
 58         }
 59     }
 60 
 61     private static void displayWords() {
 62         for (int x = 0; x < numberOfWords; x = x + 1) {
 63             System.out.println(words.get(x));
 64         }
 65     }
 66 
 67     private static void interpreter() {
 68         System.out.print(">>> ");
 69         String command = commandReader.next();
 70         if (command.equalsIgnoreCase("DISPLAY")) {
 71             interpreterDisplayCommand();
 72         } else if (command.equalsIgnoreCase("PRINT")) {
 73             interpretPrintCommand();
 74         } else if (command.equalsIgnoreCase("SWAP")) {
 75             interpretSwapCommand();
 76         } else if (command.equalsIgnoreCase("ADD")) {
 77             interpretAddCommand();
 78         } else if (command.equalsIgnoreCase("HELP")) {
 79             interpretHelpCommand();
 80         } else if (command.equalsIgnoreCase("EXIT")) {
 81             System.exit(0);
 82         } else {
 83             System.out.println("### Unrecognizable command: " + command);
 84         }
 85         interpreter();
 86     }
 87 
 88     private static void interpreterDisplayCommand() {
 89         displayWords();
 90     }
 91 
 92     private static void interpretPrintCommand() {
 93         String operand = commandReader.next();
 94         if (operand.equalsIgnoreCase("FIRST")) {
 95             System.out.println(words.get(0));
 96         } else if (operand.equalsIgnoreCase("LAST")) {
 97             System.out.println(words.get(numberOfWords - 1));
 98         } else {
 99             int index = Integer.valueOf(operand);
100             System.out.println(words.get(index - 1));
101         }
102     }
103 
104     private static void interpretSwapCommand() {
105         int position1 = commandReader.nextInt();
106         int position2 = commandReader.nextInt();
107         String temp = words.get(position1 - 1);
108         words.set(position1 - 1, words.get(position2 - 1));
109         words.set(position2 - 1, temp);
110     }
111 
112     private static void interpretAddCommand() {
113         String position = commandReader.next();
114         if (position.equalsIgnoreCase("LAST")) {
115             addLast();
116             numberOfWords = numberOfWords + 1;
117         } else if (position.equalsIgnoreCase("FIRST")) {
118             addFirst();
119             numberOfWords = numberOfWords + 1;
120         } else {
121             System.out.println("### invalid operand for add command");
122         }
123     }
124 
125     private static void interpretHelpCommand() {
126         System.out.println("HELP - display a menu of commands");
127         System.out.println("DISPLAY - display the list of numbers");
128         System.out.println("PRINT - print a number (FIRST;LAST;nth)");
129         System.out.println("SWAP - exchange two elements (nth;mth)");
130         System.out.println("ADD - add a number to the list (FIRST;LAST)");
131         System.out.println("EXIT - terminate execution of the program");
132     }
133 
134     private static void addLast() {
135         words.add(commandReader.next());
136     }
137 
138     private static void addFirst() {
139         words.add(0, commandReader.next());
140     }
141 
142 }
143