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8
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1 package howtouse;
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2
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3
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4 public class CharReader {
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5
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6 final static char EOFchar = (char) 0;
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7
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9
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8 private String text;
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9 private int textLength;
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8
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10 private int index;
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11
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12 private final char LBRANK = '[';
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13 private final char RBRANK = ']';
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14 private final char VERBAR = '|';
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17
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15 private final char COLON= ':';
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8
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16
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17
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18 CharReader() {
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19 }
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20
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9
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21 public void setText(String str) {
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22 text = str;
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23 textLength = text.length();
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24 index = 0;
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25 }
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8
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26
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27
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28 char nextChar() {
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9
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29 if (index < textLength)
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30 return text.charAt(index++);
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8
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31
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32 return EOFchar;
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33
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34 }
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35
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9
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36 String getToken() {
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8
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37
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38 int nextState = 1;
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39
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40 StringBuffer buf = new StringBuffer(256);
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41 char ch;
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42 int index = -1;
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43 while (true) {
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44 ch = nextChar();
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45 if (ch == EOFchar) return null;
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46 switch (nextState) {
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47 case 1:
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48 if (ch == LBRANK)
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49 nextState = 2;
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50 break;
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51 case 2:
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52 if (ch == LBRANK)
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53 nextState = 3;
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54 else
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55 nextState = 1;
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56 break;
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57 case 3:
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58 if (ch == RBRANK) {
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59 nextState = 4;
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60 } else if (ch == VERBAR) {
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61 index = buf.length();
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17
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62 buf.append(ch);
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63 return buf.substring(0,index);
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64 } else if (ch == COLON) {
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65 index = 0;
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66 buf.delete(0,buf.length());
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8
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67 } else {
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68 buf.append(ch);
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69 }
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70 break;
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71 case 4:
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72 if (ch == RBRANK) {
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73 if (index == -1) {
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74 return buf.toString();
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75 } else{
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76 return buf.substring(0,index);
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77 }
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78 } else {
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9
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79 return null;
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8
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80 }
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81 }
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82
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83 }
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84
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85 }
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86 }
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