1 | /***********************************************************************
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2 | * @(#)$RCSfile: Tokenizer.java,v $ $Revision: 1.6 $$Date: 2006/04/21 14:14:56 $
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3 | *
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4 | * Copyright (c) Christof Dallermassl
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5 | *
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6 | * This program is free software; you can redistribute it and/or modify
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7 | * it under the terms of the GNU Lesser General Public License (LGPL)
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8 | * as published by the Free Software Foundation; either version 2.1 of
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9 | * the License, or (at your option) any later version.
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10 | *
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11 | * This program is distributed in the hope that it will be useful,
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12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 | * GNU Lesser General Public License for more details.
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15 | *
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16 | * You should have received a copy of the GNU Lesser General Public
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17 | * License along with this program; if not, write to the
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18 | * Free Software Foundation, Inc.,
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19 | * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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20 | ***********************************************************************/
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21 |
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22 | package org.dinopolis.util.io;
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23 |
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24 | import java.io.IOException;
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25 | import java.io.InputStream;
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26 | import java.io.InputStreamReader;
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27 | import java.io.PushbackReader;
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28 | import java.io.Reader;
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29 | import java.io.StringReader;
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30 | import java.util.ArrayList;
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31 | import java.util.Iterator;
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32 | import java.util.List;
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33 |
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34 | //----------------------------------------------------------------------
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35 | /**
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36 |
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37 | * This tokenizer merges the benefits of the java.lang.StringTokenizer
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38 | * class and the java.io.StreamTokenizer class. It provides a low
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39 | * level and a high level interface to the tokenizer. The low level
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40 | * interface consists of the method pair nextToken() and getWord(),
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41 | * where the first returns the type of token in the parsing process,
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42 | * and the latter returns the String element itself.
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43 | * <p>
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44 | * The high level interface consists of the methods hasNextLine() and
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45 | * nextLine(). They use the low level interface to parse the data line
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46 | * by line and create a list of strings from it.
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47 | * <p>
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48 | * It is unsure, if it is wise to mix the usage of the high and
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49 | * the low level interface. For normal usage, the high level interface
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50 | * should be more comfortable to use and does not provide any
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51 | * drawbacks.
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52 | * <p>
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53 |
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54 | * An example for the high level interface:
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55 | * <pre>
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56 | * try
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57 | * {
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58 | * // simple example, tokenizing string, no escape, but quoted
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59 | * // works:
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60 | * System.out.println("example 1");
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61 | * Tokenizer tokenizer = new Tokenizer("text,,,\"another,text\"");
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62 | * List tokens;
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63 | * while(tokenizer.hasNextLine())
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64 | * {
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65 | * tokens = tokenizer.nextLine();
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66 | * System.out.println(tokens.get(0)); // prints 'text'
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67 | * System.out.println(tokens.get(1)); // prints ''
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68 | * System.out.println(tokens.get(2)); // prints ''
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69 | * System.out.println(tokens.get(3)); // prints 'another,text'
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70 | * }
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71 | *
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72 | * System.out.println("example 2");
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73 | * // simple example, tokenizing string, using escape char and
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74 | * // quoted strings:
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75 | * tokenizer = new Tokenizer("text,text with\\,comma,,\"another,text\"");
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76 | * tokenizer.respectEscapedCharacters(true);
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77 | * while(tokenizer.hasNextLine())
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78 | * {
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79 | * tokens = tokenizer.nextLine();
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80 | * System.out.println(tokens.get(0)); // prints 'text'
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81 | * System.out.println(tokens.get(1)); // prints 'text with, comma'
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82 | * System.out.println(tokens.get(2)); // prints ''
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83 | * System.out.println(tokens.get(3)); // prints 'another,text'
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84 | * }
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85 | * }
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86 | * catch(Exception ioe)
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87 | * {
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88 | * ioe.printStackTrace();
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89 | * }
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90 | * </pre>
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91 | * <p>
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92 | * The advantages compared to the StreamTokenizer class are: Unlike
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93 | * the StreamTokenizer, this Tokenizer class returns the delimiters as
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94 | * tokens and therefore may be used to tokenize e.g. comma separated
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95 | * files with empty fields (the StreamTokenizer handles multiple
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96 | * delimiters in a row like one delimiter).
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97 | * <p>
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98 | * The tokenizer respect quoted words, so the delimiter is ignored if
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99 | * inside quotes. And it may handle escaped characters (like an
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100 | * escaped quote character, or an escaped new line). So the line
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101 | * <code>eric,"he said, \"great!\""</code> returns <code>eric</code>
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102 | * and <code>he said, "great!"</code> as words.
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103 | * <p>
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104 | * Low level interface: The design of the Tokenizer allows to get
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105 | * empty columns as well as treat multiple delimiters in a row as one
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106 | * delimiter. For the first approach trigger the values on every
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107 | * DELIMITER and EOF token whereas for the second, trigger only on
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108 | * WORD tokens.
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109 | * <p>
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110 | * If one wants to be informed about empty words as well, use the
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111 | * Tokenizer like in the following code fragment:
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112 | * <pre>
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113 | * Tokenizer tokenizer = new Tokenizer("text,,,another text");
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114 | * String word = "";
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115 | * int token;
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116 | * while((token = tokenizer.nextToken()) != Tokenizer.EOF)
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117 | * {
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118 | * switch(token)
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119 | * {
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120 | * case Tokenizer.EOL:
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121 | * System.out.println("word: "+word);
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122 | * word = "";
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123 | * System.out.println("-------------");
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124 | * break;
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125 | * case Tokenizer.WORD:
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126 | * word = tokenizer.getWord();
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127 | * break;
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128 | * case Tokenizer.QUOTED_WORD:
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129 | * word = tokenizer.getWord() + " (quoted)";
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130 | * break;
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131 | * case Tokenizer.DELIMITER:
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132 | * System.out.println("word: "+word);
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133 | * word = "";
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134 | * break;
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135 | * default:
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136 | * System.err.println("Unknown Token: "+token);
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137 | * }
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138 | * }
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139 | * </pre>
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140 | * In this example, if the delimiter is set to a comma, a line like
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141 | * <code>column1,,,"column4,partofcolumn4"</code> would be treated correctly.
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142 | * <p>
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143 | * This tokenizer uses the LF character as end of line characters. It
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144 | * ignores any CR characters, so it can be used in windows
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145 | * environments as well.
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146 | *
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147 | * @author Christof Dallermassl
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148 | * @version $Revision: 1.6 $
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149 | */
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150 |
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151 | public class Tokenizer
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152 | {
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153 | /** the reader to read from */
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154 | protected PushbackReader reader_;
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155 | /** the buffer to create the tokens */
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156 | protected StringBuffer buffer_;
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157 | /** all characters in this string are used as delimiters */
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158 | protected String delimiters_ = ",";
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159 | /** the escape character */
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160 | protected int escapeChar_ = '\\';
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161 | /** the quote character */
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162 | protected int quoteChar_ = '"';
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163 |
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164 | /** if true, characters are treated as escaped */
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165 | protected boolean escapeMode_ = false;
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166 |
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167 | /** if true, end of line is respected */
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168 | protected boolean eolIsSignificant_ = true;
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169 | /** if true, escape characters are respected */
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170 | protected boolean respectEscapedChars_ = false;
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171 | /** if true, quoted words are respected */
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172 | protected boolean respectQuotedWords_ = true;
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173 |
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174 | /** line count */
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175 | protected int lineCount_ = 1;
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176 |
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177 | /** end of file marker */
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178 | protected boolean eofReached_ = false;
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179 |
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180 | /** the last token that was found */
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181 | protected int lastToken_ = NOT_STARTED;
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182 |
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183 | /** end of file token */
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184 | public static final int EOF = -1;
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185 | /** end of line token */
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186 | public static final int EOL = 0;
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187 | /** word token */
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188 | public static final int WORD = 1;
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189 | /** quoted word token */
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190 | public static final int QUOTED_WORD = 2;
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191 | /** delimiter token */
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192 | public static final int DELIMITER = 3;
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193 | /** error token */
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194 | public static final int ERROR = 4;
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195 | /** not started token */
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196 | public static final int NOT_STARTED = 5;
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197 |
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198 |
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199 | //----------------------------------------------------------------------
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200 | /**
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201 | * Creates a tokenizer that reads from the given string. It uses the
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202 | * comma as delimiter, does not respect escape characters but respects
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203 | * quoted words.
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204 | *
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205 | * @param string the string to read from.
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206 | */
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207 | public Tokenizer(String string)
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208 | {
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209 | this(new StringReader(string));
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210 | }
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211 |
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212 | //----------------------------------------------------------------------
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213 | /**
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214 | * Creates a tokenizer that reads from the given string. All
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215 | * characters in the given delimiters string are used as
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216 | * delimiter. The tokenizer does not respect escape characters but
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217 | * respects quoted words.
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218 | *
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219 | * @param string the string to read from.
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220 | * @param delimiters the delimiters to use.
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221 | */
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222 | public Tokenizer(String string, String delimiters)
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223 | {
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224 | this(new StringReader(string));
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225 | setDelimiters(delimiters);
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226 | }
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227 |
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228 | //----------------------------------------------------------------------
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229 | /**
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230 | * Creates a tokenizer that reads from the given string. It uses the
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231 | * comma as delimiter, does not respect escape characters but respects
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232 | * quoted words.
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233 | *
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234 | * @param inStream the stream to read from.
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235 | */
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236 | public Tokenizer(InputStream inStream)
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237 | {
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238 | this(new InputStreamReader(inStream));
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239 | }
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240 |
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241 | //----------------------------------------------------------------------
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242 | /**
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243 | * Creates a tokenizer that reads from the given reader. It uses the
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244 | * comma as delimiter, does not respect escape characters but respects
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245 | * quoted words.
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246 | *
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247 | * @param reader the reader to read from.
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248 | */
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249 | public Tokenizer(Reader reader)
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250 | {
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251 | reader_ = new PushbackReader(reader,2);
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252 | buffer_ = new StringBuffer();
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253 | }
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254 |
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255 | //----------------------------------------------------------------------
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256 | /**
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257 | * Set the delimiter character. The default is the comma.
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258 | *
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259 | * @param delimiterChar the delimiter character.
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260 | */
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261 | public void setDelimiter(int delimiterChar)
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262 | {
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263 | delimiters_ = new String(new char[]{(char)delimiterChar});
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264 | }
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265 |
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266 | //----------------------------------------------------------------------
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267 | /**
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268 | * Get the first delimiter character.
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269 | *
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270 | * @return the delimiter character.
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271 | * @deprecated use the getDelimiters() method now
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272 | */
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273 | public int getDelimiter()
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274 | {
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275 | return(delimiters_.charAt(0));
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276 | }
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277 |
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278 | //----------------------------------------------------------------------
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279 | /**
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280 | * Set the delimiter characters. All characters in the delimiters are
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281 | * used as delimiter.
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282 | *
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283 | * @param delimiters the delimiter characters.
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284 | */
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285 | public void setDelimiters(String delimiters)
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286 | {
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287 | delimiters_ = delimiters;
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288 | }
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289 |
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290 | //----------------------------------------------------------------------
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291 | /**
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292 | * Get the delimiter character.
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293 | *
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294 | * @return the delimiter character.
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295 | */
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296 | public String getDelimiters()
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297 | {
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298 | return(delimiters_);
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299 | }
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300 |
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301 | //----------------------------------------------------------------------
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302 | /**
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303 | * Set the escape character. The default is the backslash.
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304 | *
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305 | * @param escapeChar the escape character.
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306 | */
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307 | public void setEscapeChar(int escapeChar)
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308 | {
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309 | escapeChar_ = escapeChar;
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310 | }
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311 |
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312 | //----------------------------------------------------------------------
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313 | /**
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314 | * Get the escape character.
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315 | *
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316 | * @return the escape character.
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317 | */
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318 | public int getEscapeChar()
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319 | {
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320 | return(escapeChar_);
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321 | }
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322 |
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323 | //----------------------------------------------------------------------
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324 | /**
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325 | * If escape characters should be respected, set the param to
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326 | * <code>true</code>. The default is to ignore escape characters.
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327 | *
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328 | * @param respectEscaped If escape characters should be respected,
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329 | * set the param to <code>true</code>.
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330 | */
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331 | public void respectEscapedCharacters(boolean respectEscaped)
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332 | {
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333 | respectEscapedChars_ = respectEscaped;
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334 | }
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335 |
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336 | //----------------------------------------------------------------------
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337 | /**
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338 | * Returns <code>true</code>, if escape character is respected.
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339 | *
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340 | * @return <code>true</code>, if escape character is respected.
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341 | */
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342 | public boolean respectEscapedCharacters()
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343 | {
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344 | return(respectEscapedChars_);
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345 | }
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346 |
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347 | //----------------------------------------------------------------------
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348 | /**
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349 | * Get the quote character.
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350 | *
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351 | * @return the quote character.
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352 | */
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353 | public int getQuoteChar()
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354 | {
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355 | return (quoteChar_);
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356 | }
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357 |
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358 | //----------------------------------------------------------------------
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359 | /**
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360 | * Set the quote character. The default is the double quote.
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361 | *
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362 | * @param quoteChar the quote character.
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363 | */
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364 | public void setQuoteChar(int quoteChar)
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365 | {
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366 | quoteChar_ = quoteChar;
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367 | }
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368 |
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369 | //----------------------------------------------------------------------
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370 | /**
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371 | * If quoted words should be respected, set the param to
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372 | * <code>true</code>. The default is to respect quoted words.
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373 | *
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374 | * @param respectQuotes If quoted words should be respected,
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375 | * set the param to <code>true</code>.
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376 | */
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377 | public void respectQuotedWords(boolean respectQuotes)
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378 | {
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379 | respectQuotedWords_ = respectQuotes;
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380 | }
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381 |
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382 | //----------------------------------------------------------------------
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383 | /**
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384 | * Returns <code>true</code>, if quoted words are respected.
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385 | *
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386 | * @return <code>true</code>, if quoted words are respected.
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387 | */
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388 | public boolean respectQuotedWords()
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389 | {
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390 | return(respectQuotedWords_);
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391 | }
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392 |
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393 | //----------------------------------------------------------------------
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394 | /**
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395 | * If set to <code>true</code> the end of line is signaled by the EOL
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396 | * token. If set to <code>false</code> end of line is treated as a
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397 | * normal delimiter. The default value is true;
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398 | *
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399 | * @param significant if the end of line is treated as a special token
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400 | * or as a delimiter.
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401 | */
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402 | public void eolIsSignificant(boolean significant)
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403 | {
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404 | eolIsSignificant_ = significant;
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405 | }
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406 |
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407 | //----------------------------------------------------------------------
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408 | /**
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409 | * Returns <code>true</code>, if in case of an end of line detected,
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410 | * an EOL token is returned. If <code>false</code>, the end of line is
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411 | * treated as a normal delimiter.
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412 | *
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413 | * @return <code>true</code>, if in case of an end of line detected,
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414 | * an EOL token is returned. If <code>false</code>, the end of line is
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415 | * treated as a normal delimiter.
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416 | */
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417 | public boolean isEolSignificant()
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418 | {
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419 | return(eolIsSignificant_);
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420 | }
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421 |
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422 |
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423 | //----------------------------------------------------------------------
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424 | /**
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425 | * Returns the current line number of the reader.
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426 | *
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427 | * @return the current line number of the reader.
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428 | */
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429 | public int getLineNumber()
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430 | {
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431 | return(lineCount_);
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432 | }
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433 |
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434 | //----------------------------------------------------------------------
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435 | /**
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436 | * Returns the value of the token. If the token was of the type WORD,
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437 | * the word is returned.
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438 | *
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439 | * @return the value of the token.
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440 | */
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441 | public String getWord()
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442 | {
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443 | return(buffer_.toString());
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444 | }
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445 |
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446 | //----------------------------------------------------------------------
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447 | /**
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448 | * Returns the last token that was returned from the nextToken() method.
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449 | *
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450 | * @return the last token.
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451 | */
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452 | public int getLastToken()
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453 | {
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454 | return(lastToken_);
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455 | }
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456 |
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457 | //----------------------------------------------------------------------
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458 | /**
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459 | * Returns true, if the given character is seen as a delimiter. This
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460 | * method respects escape_mode, so if the escape character was found
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461 | * before, it has to act accordingly (usually, return false, even if
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462 | * the character is a delimiter).
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463 | *
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464 | * @param character the character to check for delimiter
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465 | * @return true, if the given character is seen as a delimiter.
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466 | */
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467 | protected boolean isDelimiter(int character)
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468 | {
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469 | // check for escape mode:
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470 | if(escapeMode_)
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471 | return(false);
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472 |
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473 | return(delimiters_.indexOf(character) >= 0);
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474 | }
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475 |
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476 | //----------------------------------------------------------------------
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477 | /**
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478 | * Returns true, if the given character is seen as a quote
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479 | * character. This method respects escape_mode, so if the escape
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480 | * character was found before, it has to act accordingly (usually,
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481 | * return false, even if the character is a quote character).
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482 | *
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483 | * @param character the character to check for quote.
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484 | * @return true, if the given character is seen as a quote character.
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485 | */
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486 | protected boolean isQuoteChar(int character)
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487 | {
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488 | if(!respectQuotedWords_)
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489 | return(false);
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490 |
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491 | // check for escape mode:
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492 | if(escapeMode_)
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493 | return(false);
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494 |
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495 | return(character == quoteChar_);
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496 | }
|
---|
497 |
|
---|
498 | //----------------------------------------------------------------------
|
---|
499 | /**
|
---|
500 | * Returns true, if the given character is seen as a escape
|
---|
501 | * character. This method respects escape_mode, so if the escape
|
---|
502 | * character was found before, it has to act accordingly (usually,
|
---|
503 | * return false, even if the character is a escape character).
|
---|
504 | * @param character the character to check for escape character.
|
---|
505 | * @return true, if the given character is seen as a escape character.
|
---|
506 | */
|
---|
507 | protected boolean isEscapeChar(int character)
|
---|
508 | {
|
---|
509 | if(!respectEscapedChars_)
|
---|
510 | return(false);
|
---|
511 |
|
---|
512 | // check for escape mode:
|
---|
513 | if(escapeMode_)
|
---|
514 | return(false);
|
---|
515 |
|
---|
516 | return(character == escapeChar_);
|
---|
517 | }
|
---|
518 |
|
---|
519 | //----------------------------------------------------------------------
|
---|
520 | /**
|
---|
521 | * Returns true, if the given character is seen as a end of line
|
---|
522 | * character. This method respects end of line_mode, so if the end of
|
---|
523 | * line character was found before, it has to act accordingly
|
---|
524 | * (usually, return false, even if the character is a end of line
|
---|
525 | * character).
|
---|
526 | * @param character the character to check for end of line.
|
---|
527 | * @return true, if the given character is seen as a end of line
|
---|
528 | * character.
|
---|
529 | */
|
---|
530 | protected boolean isEndOfLine(int character)
|
---|
531 | {
|
---|
532 | // check for escape mode:
|
---|
533 | if(escapeMode_)
|
---|
534 | {
|
---|
535 | if(character == '\n') // add line count, even if in escape mode!
|
---|
536 | lineCount_++;
|
---|
537 | return(false);
|
---|
538 | }
|
---|
539 | if(character == -1)
|
---|
540 | eofReached_ = true;
|
---|
541 |
|
---|
542 | return((character=='\n') || (character=='\r') || (character == -1));
|
---|
543 | }
|
---|
544 |
|
---|
545 | //----------------------------------------------------------------------
|
---|
546 | /**
|
---|
547 | * Closes the tokenizer (and the reader is uses internally).
|
---|
548 | *
|
---|
549 | * @exception IOException if an error occurred.
|
---|
550 | */
|
---|
551 | public void close()
|
---|
552 | throws IOException
|
---|
553 | {
|
---|
554 | reader_.close();
|
---|
555 | }
|
---|
556 |
|
---|
557 | //----------------------------------------------------------------------
|
---|
558 | /**
|
---|
559 | * Reads and returns the next character from the reader and checks for
|
---|
560 | * the escape character. If an escape character is read, a flag is set
|
---|
561 | * and the next character is read. A newline following the escape
|
---|
562 | * character is ignored.
|
---|
563 | *
|
---|
564 | * @return the next character.
|
---|
565 | * @exception IOException if an error occurred.
|
---|
566 | */
|
---|
567 | protected int readNextChar()
|
---|
568 | throws IOException
|
---|
569 | {
|
---|
570 | int next_char = reader_.read();
|
---|
571 | if(escapeMode_)
|
---|
572 | {
|
---|
573 | escapeMode_ = false;
|
---|
574 | }
|
---|
575 | else
|
---|
576 | {
|
---|
577 | if(isEscapeChar(next_char))
|
---|
578 | {
|
---|
579 | // ignore escape char itself:
|
---|
580 | next_char = reader_.read();
|
---|
581 |
|
---|
582 | // check for newline and ignore it:
|
---|
583 | if(isEndOfLine(next_char))
|
---|
584 | {
|
---|
585 | lineCount_++;
|
---|
586 | next_char = reader_.read();
|
---|
587 | // ignore CR:
|
---|
588 | if(next_char == '\r')
|
---|
589 | {
|
---|
590 | next_char = readNextChar();
|
---|
591 | }
|
---|
592 | }
|
---|
593 | escapeMode_ = true;
|
---|
594 | }
|
---|
595 | }
|
---|
596 | // ignore CR:
|
---|
597 | if(next_char == '\r')
|
---|
598 | {
|
---|
599 | next_char = readNextChar();
|
---|
600 | }
|
---|
601 | return(next_char);
|
---|
602 | }
|
---|
603 |
|
---|
604 | //----------------------------------------------------------------------
|
---|
605 | /**
|
---|
606 | * Returns the next token from the reader. The token's value may be
|
---|
607 | * WORD, QUOTED_WORD, EOF, EOL, or DELIMITER. In the case or WORD or
|
---|
608 | * QUOTED_WORD the actual word can be obtained by the use of the
|
---|
609 | * getWord method.
|
---|
610 | *
|
---|
611 | * @return the next token.
|
---|
612 | * @exception IOException if an error occurred.
|
---|
613 | */
|
---|
614 | public int nextToken()
|
---|
615 | throws IOException
|
---|
616 | {
|
---|
617 | buffer_.setLength(0);
|
---|
618 |
|
---|
619 | int next_char;
|
---|
620 | next_char = readNextChar();
|
---|
621 |
|
---|
622 | // handle EOF:
|
---|
623 | if(eofReached_)
|
---|
624 | {
|
---|
625 | lastToken_ = EOF;
|
---|
626 | return(EOF);
|
---|
627 | }
|
---|
628 |
|
---|
629 | // handle EOL:
|
---|
630 | if(isEndOfLine(next_char))
|
---|
631 | {
|
---|
632 | lineCount_++;
|
---|
633 | if(eolIsSignificant_)
|
---|
634 | {
|
---|
635 | lastToken_ = EOL;
|
---|
636 | return(EOL);
|
---|
637 | }
|
---|
638 | else
|
---|
639 | {
|
---|
640 | lastToken_ = DELIMITER;
|
---|
641 | return(DELIMITER);
|
---|
642 | }
|
---|
643 | }
|
---|
644 |
|
---|
645 | // handle DELIMITER
|
---|
646 | if(isDelimiter(next_char))
|
---|
647 | {
|
---|
648 | lastToken_ = DELIMITER;
|
---|
649 | return(DELIMITER);
|
---|
650 | }
|
---|
651 |
|
---|
652 | // handle quoted words:
|
---|
653 | if(isQuoteChar(next_char))
|
---|
654 | {
|
---|
655 | while(true)
|
---|
656 | {
|
---|
657 | next_char = readNextChar();
|
---|
658 | if(isEndOfLine(next_char))
|
---|
659 | {
|
---|
660 | lastToken_ = ERROR;
|
---|
661 | return(ERROR);
|
---|
662 | }
|
---|
663 | else
|
---|
664 | {
|
---|
665 | if(isQuoteChar(next_char))
|
---|
666 | {
|
---|
667 | lastToken_ = QUOTED_WORD;
|
---|
668 | return(QUOTED_WORD);
|
---|
669 | }
|
---|
670 |
|
---|
671 | // no special char, then append to buffer:
|
---|
672 | buffer_.append((char)next_char);
|
---|
673 | }
|
---|
674 | }
|
---|
675 | }
|
---|
676 |
|
---|
677 | // handle 'normal' words:
|
---|
678 | while(true)
|
---|
679 | {
|
---|
680 | buffer_.append((char)next_char);
|
---|
681 | next_char = readNextChar();
|
---|
682 | if(isDelimiter(next_char) || isEndOfLine(next_char))
|
---|
683 | {
|
---|
684 | reader_.unread(next_char);
|
---|
685 | lastToken_ = WORD;
|
---|
686 | return(WORD);
|
---|
687 | }
|
---|
688 | }
|
---|
689 | }
|
---|
690 |
|
---|
691 | //----------------------------------------------------------------------
|
---|
692 | /**
|
---|
693 | * Returns true, if the tokenizer can return another line.
|
---|
694 | *
|
---|
695 | * @return true, if the tokenizer can return another line.
|
---|
696 | * @exception IOException if an error occurred.
|
---|
697 | */
|
---|
698 | public boolean hasNextLine()
|
---|
699 | throws IOException
|
---|
700 | {
|
---|
701 | if(lastToken_ == EOF)
|
---|
702 | return(false);
|
---|
703 |
|
---|
704 | if((lastToken_ == EOL) || (lastToken_ == NOT_STARTED))
|
---|
705 | {
|
---|
706 | int next_char = readNextChar();
|
---|
707 | if(next_char == -1)
|
---|
708 | return(false);
|
---|
709 |
|
---|
710 | reader_.unread(next_char);
|
---|
711 | }
|
---|
712 | return(true);
|
---|
713 | }
|
---|
714 |
|
---|
715 |
|
---|
716 | //----------------------------------------------------------------------
|
---|
717 | /**
|
---|
718 | * Returns a list of elements (Strings) from the next line of the
|
---|
719 | * tokenizer. If there are multiple delimiters without any values in
|
---|
720 | * between, empty (zero length) strings are added to the list. They
|
---|
721 | * may be removed by the use of the {@link
|
---|
722 | * #removeZeroLengthElements(List)} method.
|
---|
723 | *
|
---|
724 | * @return a list of elements (Strings) from the next line of the
|
---|
725 | * tokenizer.
|
---|
726 | * @exception IOException if an error occurred.
|
---|
727 | */
|
---|
728 | public List<String> nextLine()
|
---|
729 | throws IOException
|
---|
730 | {
|
---|
731 | int token = nextToken();
|
---|
732 | List<String> list = new ArrayList<>();
|
---|
733 | String word = "";
|
---|
734 | // while(token != Tokenizer.EOF)
|
---|
735 | while(true)
|
---|
736 | {
|
---|
737 | switch(token)
|
---|
738 | {
|
---|
739 | case Tokenizer.WORD:
|
---|
740 | word = getWord();
|
---|
741 | break;
|
---|
742 | case Tokenizer.QUOTED_WORD:
|
---|
743 | word = getWord();
|
---|
744 | break;
|
---|
745 | case Tokenizer.DELIMITER:
|
---|
746 | list.add(word);
|
---|
747 | word = "";
|
---|
748 | break;
|
---|
749 | case Tokenizer.EOL:
|
---|
750 | case Tokenizer.EOF:
|
---|
751 | list.add(word);
|
---|
752 | return(list);
|
---|
753 | default:
|
---|
754 | System.err.println("Unknown Token: "+token);
|
---|
755 | }
|
---|
756 | token = nextToken();
|
---|
757 | }
|
---|
758 | // return(list);
|
---|
759 | }
|
---|
760 |
|
---|
761 | //----------------------------------------------------------------------
|
---|
762 | /**
|
---|
763 | * This helper method removes all zero length elements from the given
|
---|
764 | * list and returns it. The given list is not changed!
|
---|
765 | *
|
---|
766 | * @param list the list of String objects to remove the zero elements from.
|
---|
767 | * @return a copy of the given list where all zero length elements are removed.
|
---|
768 | */
|
---|
769 | public static List<String> removeZeroLengthElements(List<String> list)
|
---|
770 | {
|
---|
771 | return removeZeroLengthElements(list, false);
|
---|
772 | }
|
---|
773 |
|
---|
774 | //----------------------------------------------------------------------
|
---|
775 | /**
|
---|
776 | * This helper method trims all elements and removes all zero length
|
---|
777 | * (length is taken after trimming leading and trailing spaces) elements from the given
|
---|
778 | * list and returns it. This method copies the (trimmed and) non-zero elements to a
|
---|
779 | * new list.
|
---|
780 | *
|
---|
781 | * @param list the list of String objects to remove the zero elements from.
|
---|
782 | * @param trim if set to <code>true</code>, all leading and trailing spaces are removed from
|
---|
783 | * the elements. This is done, before the length is compared to zero (and the element
|
---|
784 | * may be removed if the length is zero). If set to <code>true</code>, elements
|
---|
785 | * that only consist of spaces are removed as well!
|
---|
786 | * @return the list where all zero length elements are remove.
|
---|
787 | */
|
---|
788 | public static List<String> removeZeroLengthElements(List<String> list, boolean trim)
|
---|
789 | {
|
---|
790 | Iterator<String> iterator = list.iterator();
|
---|
791 | String value;
|
---|
792 | List<String> new_list = new ArrayList<>();
|
---|
793 | while(iterator.hasNext())
|
---|
794 | {
|
---|
795 | value = iterator.next();
|
---|
796 | if (trim)
|
---|
797 | value = value.trim();
|
---|
798 | if(value.length() != 0)
|
---|
799 | new_list.add(value);
|
---|
800 | }
|
---|
801 | return(new_list);
|
---|
802 | }
|
---|
803 | }
|
---|