1    /* 
2     * Program featuring an arraylist to store and interactively manipulate a list of string 
3     */
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   public class WordList {
13       // VARIABLES LOCAL TO THE CLASS, AND HENCE GLOBAL TO THE METHODS
14   //    private static final int LIMIT = 1000;
15       // new arraylist called words
16       private static ArrayList<String> words = new ArrayList<> ();
17   //    private static int numberOfWords=0;
18       private static Scanner commandReader = new Scanner(System.in);
19   
20       public static void main(String[] args){
21           try{
22               // ESTABLISH THE ARRAY OF NUMBERS
23               readWords();
24               // CHECK THE DATA
25               // System.out.println("nThe original list of numbers..")
26               // displayNumber():
27               // ENTER THE INTERPRETER
28               interpreter();
29           } catch (FileNotFoundException ex) {
30               // If the file is not found, the system will catch it to tell the user
31               // to inform. then the system exit after 1 sec.
32               System.out.println("The file was not found. Please think again");
33               System.exit(-1);
34           }
35       }
36   
37       // Assuming the data file will be found in the public.html/data
38       // subdirectory of the user's home directory
39       private static Scanner establishScanner(String fn) throws FileNotFoundException{
40           String separator = File.separator;
41           String homeDirectory = System.getProperty("user.home");
42           // tell the system the direction of the file so its user/home/pubic_html/data
43           String path = homeDirectory + separator + "public_html" + separator + "CS1WorkSite" + separator + "arraylistplay" + separator;
44           String fullFileName = path + fn;
45           return new Scanner(new File(fullFileName));
46       }
47   
48       private static void readWords() throws FileNotFoundException {
49           // scanner will scan the new file in the directory given in the establishScanner methods
50           Scanner scanner = establishScanner("WordSet.txt");
51           // scanner.hasNext() is a boolean that is true if there is another token in the input.
52           while (scanner.hasNext()) {
53               words.add(scanner.next());
54           }
55       }
56   
57       private static void displayWords(){
58           // this will output everything added into the array
59           for (int x = 0; x < words.size(); x = x + 1 ){
60               System.out.println(words.get(x));
61           }
62       }
63   
64       private static void interpreter() {
65           System.out.print(">>> ");
66           // commandReader(scanner) will return the next string from the system input
67           String command = commandReader.next();
68           if (command.equalsIgnoreCase("DISPLAY")) {
69               interpreterDisplayCommand();
70           } else if (command.equalsIgnoreCase("PRINT")){
71               interpreterPrintCommmand();
72           } else if (command.equalsIgnoreCase("SWAP")){
73               interpreterSwapCommand();
74           } else if (command.equalsIgnoreCase("ADD")) {
75               interpreterAddCommand();
76           } else if (command.equalsIgnoreCase("HELP")) {
77               interpreterHelpCommand();
78           } else if (command.equalsIgnoreCase("EXIT")) {
79               System.exit(0);
80           } else {
81               System.out.println("### Unregonizable Command: " + command);
82           }
83           interpreter();
84       }
85   
86       private static void interpreterDisplayCommand() {
87           // Can't we just write this before since it's only one command????
88           displayWords();
89       }
90   
91       private static void interpreterPrintCommmand() {
92           String operand = commandReader.next();
93           if (operand.equalsIgnoreCase("First")){
94               System.out.println(words.get(0));
95           } else if (operand.equalsIgnoreCase("LAST")){
96               System.out.println(words.get(words.size()-1));
97           } else {
98               // "Integer.valueOf(operand)" convert the string operand to an integer. Super useful
99               int index = Integer.valueOf(operand);
100              System.out.println(words.get(index-1));
101          }
102      }
103  
104      private static void interpreterHelpCommand() {
105          System.out.println("HELP - display a menu of commands");
106          System.out.println("DISPLAY - display the list of words");
107          System.out.println("PRINT - print a word (FIRST;LAST;nth)");
108          System.out.println("SWAP - exchange two elements (nth;mth)");
109          System.out.println("ADD - add a word to the list (FIRST;LAST)");
110          System.out.println("EXIT - terminate execution of the program");
111      }
112  
113      private static void interpreterSwapCommand(){
114          int position1 = commandReader.nextInt();
115          int position2 = commandReader.nextInt();
116          String temp = words.get(position1-1);
117          words.set(position1-1,words.get(position2-1));
118          words.set(position2-1,temp);
119      }
120  
121      private static void interpreterAddCommand() {
122          String position = commandReader.next();
123          if (position.equalsIgnoreCase("LAST")){
124              addlast();
125          } else if (position.equalsIgnoreCase("FIRST")){
126              addFirst();
127          } else {
128              System.out.println("### invalid operand for add command");
129          }
130  //        numberOfWords = numberOfWords + 1;
131      }
132  
133      private static void addlast() {
134          words.add(commandReader.next());
135      }
136  
137      private static void addFirst() {
138          words.add(0,commandReader.next());
139      }
140  }
141