1 | /**
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2 | *#########################################################################
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3 | *
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4 | * A component of the Gatherer application, part of the Greenstone digital
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5 | * library suite from the New Zealand Digital Library Project at the
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6 | * University of Waikato, New Zealand.
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7 | *
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8 | * <BR><BR>
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9 | *
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10 | * Author: John Thompson, Greenstone Digital Library, University of Waikato
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11 | *
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12 | * <BR><BR>
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13 | *
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14 | * Copyright (C) 1999 New Zealand Digital Library Project
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15 | *
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16 | * <BR><BR>
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17 | *
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18 | * This program is free software; you can redistribute it and/or modify
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19 | * it under the terms of the GNU General Public License as published by
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20 | * the Free Software Foundation; either version 2 of the License, or
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21 | * (at your option) any later version.
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22 | *
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23 | * <BR><BR>
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24 | *
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25 | * This program is distributed in the hope that it will be useful,
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26 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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27 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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28 | * GNU General Public License for more details.
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29 | *
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30 | * <BR><BR>
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31 | *
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32 | * You should have received a copy of the GNU General Public License
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33 | * along with this program; if not, write to the Free Software
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34 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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35 | *########################################################################
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36 | */
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37 | package org.greenstone.gatherer.util;
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38 |
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39 |
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40 | /** This class functions much like a <strong>StringTokenizer</strong> in that it tokenizes a long string into tokens, however this tokenizer cleverly notices HTML formatting tags. */
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41 | public class HTMLStringTokenizer {
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42 | /** The current position in the source string. */
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43 | private int pos = 0;
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44 | /** The current token, usually created by the last nextToken call. */
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45 | private String current = null;
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46 | /** The previous token. */
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47 | private String previous = null;
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48 | /** The string to be tokenized, including any HTML markup. */
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49 | private String source = null;
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50 | /** Constructor.
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51 | * @param source The source <strong>String</strong> to be tokenized.
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52 | */
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53 | public HTMLStringTokenizer(String source) {
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54 | this.source = source;
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55 | // Parse the first token.
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56 | parseToken();
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57 | }
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58 |
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59 | /** Determines if there are still tokens remaining unparsed in the source.
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60 | * @return A <strong>boolean</strong> which is <i>true</i> if there are more tokens.
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61 | */
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62 | public boolean hasMoreTokens() {
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63 | if(current != null && current.length() > 0) {
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64 | return true;
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65 | }
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66 | return false;
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67 | }
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68 |
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69 | /** Determines if the tag currently being returned by sameToken is a tag.
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70 | * @return A <strong>boolean</strong> indicating if the token is a tag.
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71 | */
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72 | public boolean isTag() {
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73 | if(previous.startsWith("<") && previous.endsWith(">")) {
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74 | return true;
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75 | }
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76 | return false;
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77 | }
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78 |
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79 | /** Retrieves the next token.
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80 | * @return A <strong>String</strong> representing the token.
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81 | */
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82 | public String nextToken() {
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83 | previous = current;
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84 | // Get the next token.
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85 | parseToken();
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86 | // Return previous.
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87 | return previous;
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88 | }
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89 |
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90 | /** Parses the next token and stores it in current.
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91 | */
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92 | private void parseToken() {
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93 | boolean found = false;
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94 | boolean tag = false;
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95 | boolean text = false;
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96 | // Reset current
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97 | current = "";
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98 | // Parse away
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99 | dumpWhiteSpace();
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100 | while(pos < source.length() && !found) {
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101 | char c = (char)source.charAt(pos);
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102 | if(!tag && !text) {
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103 | if(c == '<') {
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104 | tag = true;
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105 | }
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106 | else {
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107 | text = true;
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108 | }
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109 | current = current + c;
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110 | }
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111 | // Reading a tag. Watch only for '>'.
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112 | else if(tag) {
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113 | if(c == '>') {
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114 | found = true;
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115 | }
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116 | current = current + c;
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117 | }
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118 | // Reading text. Watch for ' ' and '<'. Rollback '<'.
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119 | else if(text) {
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120 | if(c == ' ') {
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121 | found = true;
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122 | }
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123 | else if(c == '<') {
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124 | found = true;
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125 | pos--;
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126 | }
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127 | else {
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128 | current = current + c;
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129 | }
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130 | }
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131 | pos++;
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132 | }
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133 | }
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134 |
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135 | /** Method to ignore whitespace in the source.
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136 | */
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137 | private void dumpWhiteSpace() {
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138 | while(pos < source.length() && source.charAt(pos) == ' ') {
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139 | pos++;
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140 | }
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141 | }
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142 | }
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