1    /* 
2     * Program featuring an array to store and interactively manipulate a list of numbers. 
3     */
4    package arrayplay;
5    
6    import java.io.File;
7    import java.io.FileNotFoundException;
8    import java.io.IOException;
9    import java.util.Scanner;
10   
11   public class NumberList {
12       // VARIABLES LOCAL TO THE CLASS, AND HENCE GLOBAL TO THE METHODS
13       private static final int LIMIT = 1000;
14       private static int[] numbers = new int[LIMIT];
15       private static int numberOfNumbers = 0;
16       private static Scanner commandReader = new Scanner(System.in);
17   
18       public static void main(String[] args) {
19           try {
20               // ESTABLISH THE ARRAY OF NUMBERS
21               readNumbers();
22               // CHECK THE DATA
23               // System.out.println("\nThe original list of numbers ..."); 
24               // displayNumbers();
25               // ENTER THE INTERPRETER
26               interpreter();
27           } catch (IOException ex) {
28               System.out.println("The file was not found. Please think again.");
29               System.exit(-1);
30           }
31       }
32   
33       //Make Compatible with my windows computer
34       public static String pathBuilder(){
35           String separator = System.getProperty("file.separator");
36           String home = null;
37   
38           //Make Program Compatible With Windows (I use windows :P )
39           if(System.getProperty("os.name").startsWith("Windows")) {
40               home = System.getProperty("user.dir");
41           }
42           else if(System.getProperty("os.name").startsWith("Windows 10")) {
43               home = System.getProperty("user.dir");
44           }
45           else {
46               home = System.getProperty("user.home");
47           }
48           String path = home + separator + "CS1Files" + separator + "data" + separator;
49           return path;
50       }
51   
52       // Assuming that the data file will be found in the public_html/data
53       // subdirectory of the user’s home directory.
54       private static Scanner establishScanner(String fn, String path) throws FileNotFoundException {
55           String fullFileName = path + fn;
56           return new Scanner(new File(fullFileName));
57       }
58   
59   
60       private static void readNumbers() throws FileNotFoundException {
61           Scanner scanner = establishScanner("NumberSet.txt", pathBuilder());
62           while (scanner.hasNext()) {
63               numbers[numberOfNumbers] = scanner.nextInt();
64               numberOfNumbers = numberOfNumbers + 1;
65           }
66       }
67   
68       private static void displayNumbers() {
69           for (int x = 0; x < numberOfNumbers; x = x + 1) {
70               System.out.println(numbers[x]);
71           }
72       }
73   
74       private static void interpreter(){
75           System.out.print(">>> ");
76           String command = commandReader.next();
77           if (command.equalsIgnoreCase("DISPLAY")) {
78               interpreterDisplayCommand();
79           } else if (command.equalsIgnoreCase("PRINT")) {
80               interpretPrintCommand();
81           } else if (command.equalsIgnoreCase("SWAP")) {
82               interpretSwapCommand();
83           } else if (command.equalsIgnoreCase("ADD")) {
84               interpretAddCommand();
85           } else if (command.equalsIgnoreCase("HELP")) {
86               interpretHelpCommand();
87           } else if(command.equalsIgnoreCase("CLEAR")) {
88               interpretClearCommand();
89           } else if(command.equalsIgnoreCase("LS")) {
90               interpretListCommand(pathBuilder());
91           } else if (command.equalsIgnoreCase("EXIT")) {
92               System.exit(0);
93           } else {
94               System.out.println("### Unrecognizable command: " + command);
95           }
96           interpreter();
97       }
98   
99       private static void interpreterDisplayCommand() {
100          displayNumbers();
101      }
102  
103      private static void interpretPrintCommand() {
104          String operand = commandReader.next();
105          if (operand.equalsIgnoreCase("FIRST")) {
106              System.out.println(numbers[0]);
107          } else if (operand.equalsIgnoreCase("LAST")) {
108              System.out.println(numbers[numberOfNumbers - 1]);
109          } else {
110              int index = Integer.valueOf(operand);
111              System.out.println(numbers[index - 1]);
112          }
113      }
114  
115      private static void interpretHelpCommand() {
116          System.out.println("HELP - display a menu of commands");
117          System.out.println("DISPLAY - display the list of numbers");
118          System.out.println("PRINT - print a number (FIRST;LAST;nth)");
119          System.out.println("SWAP - exchange two elements (nth;mth)");
120          System.out.println("ADD - add a number to the list (FIRST;LAST)");
121          System.out.println("CLEAR - clears the console");
122          System.out.println("LS - lists file in data directory");
123          System.out.println("EXIT - terminate execution of the program");
124      }
125  
126      private static void interpretSwapCommand() {
127          int position1 = commandReader.nextInt();
128          int position2 = commandReader.nextInt();
129          int temp = numbers[position1 - 1];
130          numbers[position1 - 1] = numbers[position2 - 1];
131          numbers[position2 - 1] = temp;
132      }
133  
134      private static void interpretAddCommand() {
135          String position = commandReader.next();
136          if (position.equalsIgnoreCase("LAST")) {
137              addLast();
138          } else if (position.equalsIgnoreCase("FIRST")) {
139              addFirst();
140          } else {
141              System.out.println("### invalid operand for add command");
142          }
143          numberOfNumbers = numberOfNumbers + 1;
144      }
145  
146  
147      private static void interpretClearCommand(){
148          int intelliJConsoleHistorySize = 300;
149  
150          for (int i = 0; i < intelliJConsoleHistorySize;++i) {
151              System.out.println();
152  
153          }
154      }
155  
156      private static void interpretListCommand(String path){
157          File dataFolder = new File(path);
158          File[] listOfFiles = dataFolder.listFiles();
159          for( File element: listOfFiles) {
160              System.out.println(element);
161          }
162      }
163  
164      private static void addLast() {
165          numbers[numberOfNumbers] = commandReader.nextInt();
166      }
167  
168      private static void addFirst() {
169          for (int x = numberOfNumbers; x > 0; x = x - 1) {
170              numbers[x] = numbers[x - 1];
171          }
172          numbers[0] = commandReader.nextInt();
173      }
174  }