1 | // License: GPL. Copyright 2007 by Immanuel Scholz and others
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2 | package org.openstreetmap.josm.actions.search;
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3 |
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4 | import java.io.IOException;
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5 | import java.io.Reader;
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6 |
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7 | import org.openstreetmap.josm.actions.search.SearchCompiler.ParseError;
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8 |
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9 | public class PushbackTokenizer {
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10 | private final Reader search;
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11 |
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12 | private Token currentToken;
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13 | private String currentText;
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14 | private int c;
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15 |
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16 | public PushbackTokenizer(Reader search) {
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17 | this.search = search;
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18 | getChar();
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19 | }
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20 |
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21 | public enum Token {NOT, OR, LEFT_PARENT, RIGHT_PARENT, COLON, EQUALS, KEY, EOF}
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22 |
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23 | private void getChar() {
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24 | try {
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25 | c = search.read();
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26 | } catch (IOException e) {
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27 | throw new RuntimeException(e.getMessage(), e);
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28 | }
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29 | }
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30 |
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31 | /**
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32 | * The token returned is <code>null</code> or starts with an identifier character:
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33 | * - for an '-'. This will be the only character
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34 | * : for an key. The value is the next token
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35 | * | for "OR"
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36 | * ' ' for anything else.
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37 | * @return The next token in the stream.
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38 | */
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39 | public Token nextToken() {
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40 | if (currentToken != null) {
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41 | Token result = currentToken;
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42 | currentToken = null;
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43 | return result;
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44 | }
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45 |
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46 | while (Character.isWhitespace(c)) {
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47 | getChar();
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48 | }
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49 | switch (c) {
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50 | case -1:
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51 | getChar();
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52 | return Token.EOF;
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53 | case ':':
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54 | getChar();
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55 | return Token.COLON;
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56 | case '=':
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57 | getChar();
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58 | return Token.EQUALS;
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59 | case '-':
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60 | getChar();
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61 | return Token.NOT;
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62 | case '(':
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63 | getChar();
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64 | return Token.LEFT_PARENT;
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65 | case ')':
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66 | getChar();
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67 | return Token.RIGHT_PARENT;
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68 | case '|':
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69 | getChar();
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70 | return Token.OR;
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71 | case '"':
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72 | {
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73 | StringBuilder s = new StringBuilder();
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74 | while (c != -1 && c != '"') {
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75 | s.append((char)c);
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76 | getChar();
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77 | }
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78 | getChar();
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79 | currentText = s.toString();
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80 | return Token.KEY;
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81 | }
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82 | default:
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83 | {
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84 | StringBuilder s = new StringBuilder();
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85 | while (!(c == -1 || Character.isWhitespace(c) || c == '"'|| c == ':' || c == '(' || c == ')' || c == '|' || c == '=')) {
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86 | s.append((char)c);
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87 | getChar();
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88 | }
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89 | currentText = s.toString();
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90 | if ("or".equals(currentText))
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91 | return Token.OR;
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92 | else
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93 | return Token.KEY;
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94 | }
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95 | }
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96 | }
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97 |
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98 | public boolean readIfEqual(Token token) {
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99 | Token nextTok = nextToken();
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100 | if (nextTok == null ? token == null : nextTok == token)
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101 | return true;
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102 | currentToken = nextTok;
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103 | return false;
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104 | }
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105 |
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106 | public String readText() {
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107 | Token nextTok = nextToken();
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108 | if (nextTok == Token.KEY)
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109 | return currentText;
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110 | currentToken = nextTok;
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111 | return null;
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112 | }
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113 |
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114 | public String readText(String errorMessage) throws ParseError {
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115 | String text = readText();
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116 | if (text == null)
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117 | throw new ParseError(errorMessage);
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118 | else
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119 | return text;
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120 | }
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121 |
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122 | public String getText() {
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123 | return currentText;
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124 | }
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125 | }
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