svn-gvsig-desktop / trunk / org.gvsig.desktop / org.gvsig.desktop.compat.cdc / org.gvsig.remoteclient / src / main / java / org / gvsig / remoteclient / wfs / filters / ParseExpressions.java @ 40769
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1 | 40559 | jjdelcerro | /**
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2 | * gvSIG. Desktop Geographic Information System.
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3 | *
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4 | * Copyright (C) 2007-2013 gvSIG Association.
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5 | *
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6 | * This program is free software; you can redistribute it and/or
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7 | * modify it under the terms of the GNU General Public License
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8 | * as published by the Free Software Foundation; either version 3
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9 | * of 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 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 General Public License
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17 | * along with this program; if not, write to the Free Software
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18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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19 | * MA 02110-1301, USA.
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20 | *
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21 | * For any additional information, do not hesitate to contact us
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22 | * at info AT gvsig.com, or visit our website www.gvsig.com.
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23 | */
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24 | 40435 | jjdelcerro | package org.gvsig.remoteclient.wfs.filters; |
25 | |||
26 | import java.util.ArrayList; |
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27 | |||
28 | /**
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29 | * It parses a SQL expression (just the where part) and seperates
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30 | * it in "sub-expresion". A sub-expresion could be a separator ('(' or ')'),
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31 | * a logical operator ('And', 'Not' or 'Or') or a expresion (A op B).
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32 | *
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33 | * @author Jorge Piera Llodr? (piera_jor@gva.es)
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34 | */
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35 | public class ParseExpressions { |
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36 | |||
37 | /**
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38 | * It parses a expression and return one arrayList with
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39 | * the separated words
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40 | * @param expression
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41 | * @return
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42 | */
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43 | public ArrayList parseExpression(String expression){ |
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44 | ArrayList expressions = new ArrayList(); |
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45 | |||
46 | char[] chars = expression.toCharArray(); |
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47 | int i=0; |
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48 | while (i<chars.length){
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49 | if (chars[i] == '('){ |
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50 | expressions.add("(");
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51 | i++; |
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52 | }else if(chars[i] == ')'){ |
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53 | expressions.add(")");
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54 | i++; |
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55 | }else if(chars[i] == ' '){ |
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56 | i++; |
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57 | }else{
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58 | int desp = getShift(chars,i);
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59 | expressions.add(expression.substring(i,i + desp)); |
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60 | i = i + desp; |
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61 | } |
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62 | } |
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63 | return expressions;
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64 | } |
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65 | |||
66 | /**
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67 | * Gets the shift of the next expression.
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68 | * @param chars
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69 | * @param position
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70 | * @return
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71 | */
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72 | private int getShift(char[] chars,int position){ |
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73 | int shift = 0; |
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74 | shift = isAndOperator(chars,position); |
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75 | if (shift == 0){ |
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76 | shift = isOrOperator(chars,position); |
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77 | if (shift == 0){ |
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78 | shift = isNotOperator(chars,position); |
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79 | if (shift == 0){ |
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80 | shift = isExpression(chars,position); |
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81 | } |
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82 | } |
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83 | } |
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84 | return shift;
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85 | } |
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86 | |||
87 | private int isExpression(char[] chars,int position){ |
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88 | int desp = 0; |
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89 | for (int i=position ;i<chars.length ; i++){ |
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90 | if (chars[i] == ')'){ |
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91 | break;
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92 | } |
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93 | desp++; |
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94 | } |
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95 | return desp;
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96 | } |
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97 | |||
98 | /**
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99 | * Return true if the next array is a AND operator
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100 | * @param chars
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101 | * @param position
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102 | * @return
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103 | */
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104 | private int isAndOperator(char[] chars,int position){ |
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105 | if (chars[position] == 'A' && |
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106 | chars[position+1] == 'N' && |
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107 | chars[position+2] == 'D' && |
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108 | chars[position+3] == ' '){ |
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109 | return 3; |
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110 | } |
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111 | return 0; |
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112 | } |
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113 | |||
114 | /**
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115 | * Return true if the next array is a OR operator
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116 | * @param chars
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117 | * @param position
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118 | * @return
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119 | */
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120 | private int isOrOperator(char[] chars,int position){ |
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121 | if (chars[position] == 'O' && |
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122 | chars[position+1] == 'R' && |
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123 | chars[position+2] == ' '){ |
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124 | return 2; |
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125 | } |
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126 | return 0; |
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127 | } |
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128 | |||
129 | /**
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130 | * Return true if the next array is a NOT operator
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131 | * @param chars
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132 | * @param position
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133 | * @return
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134 | */
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135 | private int isNotOperator(char[] chars,int position){ |
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136 | if (chars[position] == 'N' && |
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137 | chars[position+1] == 'O' && |
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138 | chars[position+2] == 'T' && |
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139 | chars[position+3] == ' '){ |
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140 | return 3; |
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141 | } |
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142 | return 0; |
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143 | } |
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144 | |||
145 | } |