1 | /* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for |
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2 | * full list of contributors). Published under the Clear BSD license. |
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3 | * See http://svn.openlayers.org/trunk/openlayers/license.txt for the |
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4 | * full text of the license. */ |
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5 | |
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6 | /** |
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7 | * @requires Gears/gears_init.js |
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8 | * @requires OpenLayers/Protocol/SQL.js |
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9 | * @requires OpenLayers/Format/JSON.js |
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10 | * @requires OpenLayers/Format/WKT.js |
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11 | */ |
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12 | |
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13 | /** |
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14 | * Class: OpenLayers.Protocol.SQL.Gears |
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15 | * This Protocol stores feature in the browser via the Gears Database module |
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16 | * <http://code.google.com/apis/gears/api_database.html>. |
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17 | * |
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18 | * The main advantage is that all the read, create, update and delete operations |
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19 | * can be done offline. |
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20 | * |
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21 | * Inherits from: |
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22 | * - <OpenLayers.Protocol.SQL> |
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23 | */ |
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24 | OpenLayers.Protocol.SQL.Gears = OpenLayers.Class(OpenLayers.Protocol.SQL, { |
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25 | |
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26 | /** |
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27 | * Property: FID_PREFIX |
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28 | * {String} |
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29 | */ |
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30 | FID_PREFIX: '__gears_fid__', |
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31 | |
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32 | /** |
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33 | * Property: NULL_GEOMETRY |
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34 | * {String} |
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35 | */ |
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36 | NULL_GEOMETRY: '__gears_null_geometry__', |
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37 | |
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38 | /** |
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39 | * Property: NULL_FEATURE_STATE |
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40 | * {String} |
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41 | */ |
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42 | NULL_FEATURE_STATE: '__gears_null_feature_state__', |
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43 | |
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44 | /** |
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45 | * Property: jsonParser |
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46 | * {<OpenLayers.Format.JSON>} |
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47 | */ |
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48 | jsonParser: null, |
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49 | |
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50 | /** |
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51 | * Property: wktParser |
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52 | * {<OpenLayers.Format.WKT>} |
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53 | */ |
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54 | wktParser: null, |
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55 | |
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56 | /** |
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57 | * Property: fidRegExp |
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58 | * {RegExp} Regular expression to know whether a feature was |
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59 | * created in offline mode. |
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60 | */ |
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61 | fidRegExp: null, |
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62 | |
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63 | /** |
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64 | * Property: saveFeatureState |
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65 | * {Boolean} Whether to save the feature state (<OpenLayers.State>) |
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66 | * into the database, defaults to true. |
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67 | */ |
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68 | saveFeatureState: true, |
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69 | |
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70 | /** |
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71 | * Property: typeOfFid |
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72 | * {String} The type of the feature identifier, either "number" or |
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73 | * "string", defaults to "string". |
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74 | */ |
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75 | typeOfFid: "string", |
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76 | |
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77 | /** |
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78 | * Property: db |
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79 | * {GearsDatabase} |
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80 | */ |
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81 | db: null, |
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82 | |
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83 | /** |
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84 | * Constructor: OpenLayers.Protocol.SQL.Gears |
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85 | */ |
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86 | initialize: function(options) { |
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87 | if (!this.supported()) { |
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88 | return; |
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89 | } |
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90 | OpenLayers.Protocol.SQL.prototype.initialize.apply(this, [options]); |
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91 | this.jsonParser = new OpenLayers.Format.JSON(); |
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92 | this.wktParser = new OpenLayers.Format.WKT(); |
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93 | |
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94 | this.fidRegExp = new RegExp('^' + this.FID_PREFIX); |
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95 | this.initializeDatabase(); |
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96 | |
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97 | |
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98 | }, |
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99 | |
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100 | /** |
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101 | * Method: initializeDatabase |
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102 | */ |
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103 | initializeDatabase: function() { |
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104 | this.db = google.gears.factory.create('beta.database'); |
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105 | this.db.open(this.databaseName); |
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106 | this.db.execute( |
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107 | "CREATE TABLE IF NOT EXISTS " + this.tableName + |
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108 | " (fid TEXT UNIQUE, geometry TEXT, properties TEXT," + |
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109 | " state TEXT)"); |
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110 | }, |
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111 | |
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112 | /** |
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113 | * APIMethod: destroy |
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114 | * Clean up the protocol. |
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115 | */ |
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116 | destroy: function() { |
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117 | this.db.close(); |
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118 | this.db = null; |
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119 | |
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120 | this.jsonParser = null; |
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121 | this.wktParser = null; |
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122 | |
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123 | OpenLayers.Protocol.SQL.prototype.destroy.apply(this); |
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124 | }, |
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125 | |
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126 | /** |
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127 | * APIMethod: supported |
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128 | * Determine whether a browser supports Gears |
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129 | * |
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130 | * Returns: |
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131 | * {Boolean} The browser supports Gears |
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132 | */ |
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133 | supported: function() { |
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134 | return !!(window.google && google.gears); |
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135 | }, |
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136 | |
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137 | /** |
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138 | * APIMethod: read |
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139 | * Read all features from the database and return a |
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140 | * <OpenLayers.Protocol.Response> instance. If the options parameter |
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141 | * contains a callback attribute, the function is called with the response |
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142 | * as a parameter. |
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143 | * |
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144 | * Parameters: |
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145 | * options - {Object} Optional object for configuring the request; it |
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146 | * can have the {Boolean} property "noFeatureStateReset" which |
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147 | * specifies if the state of features read from the Gears |
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148 | * database must be reset to null, if "noFeatureStateReset" |
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149 | * is undefined or false then each feature's state is reset |
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150 | * to null, if "noFeatureStateReset" is true the feature state |
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151 | * is preserved. |
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152 | * |
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153 | * Returns: |
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154 | * {<OpenLayers.Protocol.Response>} An <OpenLayers.Protocol.Response> |
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155 | * object. |
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156 | */ |
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157 | read: function(options) { |
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158 | OpenLayers.Protocol.prototype.read.apply(this, arguments); |
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159 | options = OpenLayers.Util.applyDefaults(options, this.options); |
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160 | |
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161 | var feature, features = []; |
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162 | var rs = this.db.execute("SELECT * FROM " + this.tableName); |
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163 | while (rs.isValidRow()) { |
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164 | feature = this.unfreezeFeature(rs); |
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165 | if (this.evaluateFilter(feature, options.filter)) { |
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166 | if (!options.noFeatureStateReset) { |
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167 | feature.state = null; |
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168 | } |
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169 | features.push(feature); |
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170 | } |
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171 | rs.next(); |
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172 | } |
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173 | rs.close(); |
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174 | |
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175 | var resp = new OpenLayers.Protocol.Response({ |
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176 | code: OpenLayers.Protocol.Response.SUCCESS, |
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177 | requestType: "read", |
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178 | features: features |
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179 | }); |
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180 | |
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181 | if (options && options.callback) { |
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182 | options.callback.call(options.scope, resp); |
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183 | } |
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184 | |
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185 | return resp; |
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186 | }, |
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187 | |
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188 | /** |
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189 | * Method: unfreezeFeature |
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190 | * |
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191 | * Parameters: |
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192 | * row - {ResultSet} |
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193 | * |
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194 | * Returns: |
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195 | * {<OpenLayers.Feature.Vector>} |
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196 | */ |
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197 | unfreezeFeature: function(row) { |
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198 | var feature; |
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199 | var wkt = row.fieldByName('geometry'); |
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200 | if (wkt == this.NULL_GEOMETRY) { |
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201 | feature = new OpenLayers.Feature.Vector(); |
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202 | } else { |
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203 | feature = this.wktParser.read(wkt); |
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204 | } |
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205 | |
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206 | feature.attributes = this.jsonParser.read( |
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207 | row.fieldByName('properties')); |
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208 | |
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209 | feature.fid = this.extractFidFromField(row.fieldByName('fid')); |
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210 | |
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211 | var state = row.fieldByName('state'); |
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212 | if (state == this.NULL_FEATURE_STATE) { |
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213 | state = null; |
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214 | } |
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215 | feature.state = state; |
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216 | |
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217 | return feature; |
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218 | }, |
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219 | |
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220 | /** |
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221 | * Method: extractFidFromField |
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222 | * |
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223 | * Parameters: |
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224 | * field - {String} |
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225 | * |
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226 | * Returns |
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227 | * {String} or {Number} The fid. |
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228 | */ |
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229 | extractFidFromField: function(field) { |
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230 | if (!field.match(this.fidRegExp) && this.typeOfFid == "number") { |
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231 | field = parseFloat(field); |
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232 | } |
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233 | return field; |
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234 | }, |
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235 | |
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236 | /** |
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237 | * APIMethod: create |
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238 | * Create new features into the database. |
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239 | * |
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240 | * Parameters: |
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241 | * features - {Array({<OpenLayers.Feature.Vector>})} or |
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242 | * {<OpenLayers.Feature.Vector>} The features to create in |
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243 | * the database. |
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244 | * options - {Object} Optional object for configuring the request. |
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245 | * |
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246 | * Returns: |
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247 | * {<OpenLayers.Protocol.Response>} An <OpenLayers.Protocol.Response> |
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248 | * object. |
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249 | */ |
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250 | create: function(features, options) { |
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251 | options = OpenLayers.Util.applyDefaults(options, this.options); |
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252 | |
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253 | var resp = this.createOrUpdate(features); |
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254 | resp.requestType = "create"; |
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255 | |
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256 | if (options && options.callback) { |
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257 | options.callback.call(options.scope, resp); |
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258 | } |
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259 | |
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260 | return resp; |
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261 | }, |
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262 | |
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263 | /** |
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264 | * APIMethod: update |
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265 | * Construct a request updating modified feature. |
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266 | * |
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267 | * Parameters: |
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268 | * features - {Array({<OpenLayers.Feature.Vector>})} or |
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269 | * {<OpenLayers.Feature.Vector>} The features to update in |
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270 | * the database. |
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271 | * options - {Object} Optional object for configuring the request. |
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272 | * |
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273 | * Returns: |
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274 | * {<OpenLayers.Protocol.Response>} An <OpenLayers.Protocol.Response> |
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275 | * object. |
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276 | */ |
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277 | update: function(features, options) { |
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278 | options = OpenLayers.Util.applyDefaults(options, this.options); |
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279 | |
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280 | var resp = this.createOrUpdate(features); |
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281 | resp.requestType = "update"; |
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282 | |
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283 | if (options && options.callback) { |
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284 | options.callback.call(options.scope, resp); |
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285 | } |
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286 | |
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287 | return resp; |
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288 | }, |
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289 | |
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290 | /** |
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291 | * Method: createOrUpdate |
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292 | * Construct a request for updating or creating features in the |
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293 | * database. |
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294 | * |
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295 | * Parameters: |
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296 | * features - {Array({<OpenLayers.Feature.Vector>})} or |
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297 | * {<OpenLayers.Feature.Vector>} The feature to create or update |
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298 | * in the database. |
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299 | * |
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300 | * Returns: |
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301 | * {<OpenLayers.Protocol.Response>} An <OpenLayers.Protocol.Response> |
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302 | * object. |
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303 | */ |
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304 | createOrUpdate: function(features) { |
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305 | if (!(features instanceof Array)) { |
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306 | features = [features]; |
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307 | } |
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308 | |
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309 | var i, len = features.length, feature; |
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310 | var insertedFeatures = new Array(len); |
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311 | |
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312 | for (i = 0; i < len; i++) { |
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313 | feature = features[i]; |
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314 | var params = this.freezeFeature(feature); |
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315 | this.db.execute( |
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316 | "REPLACE INTO " + this.tableName + |
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317 | " (fid, geometry, properties, state)" + |
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318 | " VALUES (?, ?, ?, ?)", |
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319 | params); |
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320 | |
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321 | var clone = feature.clone(); |
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322 | clone.fid = this.extractFidFromField(params[0]); |
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323 | insertedFeatures[i] = clone; |
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324 | } |
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325 | |
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326 | return new OpenLayers.Protocol.Response({ |
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327 | code: OpenLayers.Protocol.Response.SUCCESS, |
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328 | features: insertedFeatures, |
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329 | reqFeatures: features |
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330 | }); |
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331 | }, |
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332 | |
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333 | /** |
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334 | * Method: freezeFeature |
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335 | * |
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336 | * Parameters: |
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337 | * feature - {<OpenLayers.Feature.Vector>} |
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338 | * state - {String} The feature state to store in the database. |
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339 | * |
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340 | * Returns: |
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341 | * {Array} |
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342 | */ |
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343 | freezeFeature: function(feature) { |
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344 | // 2 notes: |
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345 | // - fid might not be a string |
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346 | // - getFeatureStateForFreeze needs the feature fid to it's stored |
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347 | // in the feature here |
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348 | feature.fid = feature.fid != null ? |
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349 | "" + feature.fid : OpenLayers.Util.createUniqueID(this.FID_PREFIX); |
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350 | |
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351 | var geometry = feature.geometry != null ? |
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352 | feature.geometry.toString() : this.NULL_GEOMETRY; |
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353 | |
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354 | var properties = this.jsonParser.write(feature.attributes); |
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355 | |
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356 | var state = this.getFeatureStateForFreeze(feature); |
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357 | |
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358 | return [feature.fid, geometry, properties, state]; |
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359 | }, |
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360 | |
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361 | /** |
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362 | * Method: getFeatureStateForFreeze |
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363 | * Get the state of the feature to store into the database. |
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364 | * |
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365 | * Parameters: |
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366 | * feature - {<OpenLayers.Feature.Vector>} The feature. |
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367 | * |
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368 | * Returns |
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369 | * {String} The state |
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370 | */ |
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371 | getFeatureStateForFreeze: function(feature) { |
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372 | var state; |
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373 | if (!this.saveFeatureState) { |
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374 | state = this.NULL_FEATURE_STATE; |
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375 | } else if (this.createdOffline(feature)) { |
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376 | // if the feature was created in offline mode, its |
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377 | // state must remain INSERT |
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378 | state = OpenLayers.State.INSERT; |
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379 | } else { |
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380 | state = feature.state; |
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381 | } |
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382 | return state; |
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383 | }, |
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384 | |
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385 | /** |
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386 | * APIMethod: delete |
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387 | * Delete features from the database. |
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388 | * |
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389 | * Parameters: |
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390 | * features - {Array({<OpenLayers.Feature.Vector>})} or |
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391 | * {<OpenLayers.Feature.Vector>} |
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392 | * options - {Object} Optional object for configuring the request. |
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393 | * This object is modified and should not be reused. |
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394 | * |
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395 | * Returns: |
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396 | * {<OpenLayers.Protocol.Response>} An <OpenLayers.Protocol.Response> |
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397 | * object. |
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398 | */ |
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399 | "delete": function(features, options) { |
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400 | if (!(features instanceof Array)) { |
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401 | features = [features]; |
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402 | } |
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403 | |
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404 | options = OpenLayers.Util.applyDefaults(options, this.options); |
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405 | |
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406 | var i, len, feature; |
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407 | for (i = 0, len = features.length; i < len; i++) { |
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408 | feature = features[i]; |
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409 | |
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410 | // if saveFeatureState is set to true and if the feature wasn't created |
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411 | // in offline mode we don't delete it in the database but just update |
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412 | // it state column |
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413 | if (this.saveFeatureState && !this.createdOffline(feature)) { |
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414 | var toDelete = feature.clone(); |
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415 | toDelete.fid = feature.fid; |
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416 | if (toDelete.geometry) { |
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417 | toDelete.geometry.destroy(); |
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418 | toDelete.geometry = null; |
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419 | } |
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420 | toDelete.state = feature.state; |
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421 | this.createOrUpdate(toDelete); |
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422 | } else { |
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423 | this.db.execute( |
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424 | "DELETE FROM " + this.tableName + |
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425 | " WHERE fid = ?", [feature.fid]); |
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426 | } |
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427 | } |
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428 | |
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429 | var resp = new OpenLayers.Protocol.Response({ |
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430 | code: OpenLayers.Protocol.Response.SUCCESS, |
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431 | requestType: "delete", |
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432 | reqFeatures: features |
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433 | }); |
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434 | |
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435 | if (options && options.callback) { |
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436 | options.callback.call(options.scope, resp); |
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437 | } |
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438 | |
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439 | return resp; |
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440 | }, |
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441 | |
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442 | /** |
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443 | * Method: createdOffline |
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444 | * Returns true if the feature had a feature id when it was created in |
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445 | * the Gears database, false otherwise; this is determined by |
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446 | * checking the form of the feature's fid value. |
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447 | * |
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448 | * Parameters: |
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449 | * feature - {<OpenLayers.Feature.Vector>} |
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450 | * |
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451 | * Returns: |
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452 | * {Boolean} |
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453 | */ |
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454 | createdOffline: function(feature) { |
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455 | return (typeof feature.fid == "string" && |
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456 | !!(feature.fid.match(this.fidRegExp))); |
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457 | }, |
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458 | |
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459 | /** |
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460 | * APIMethod: commit |
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461 | * Go over the features and for each take action |
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462 | * based on the feature state. Possible actions are create, |
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463 | * update and delete. |
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464 | * |
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465 | * Parameters: |
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466 | * features - {Array({<OpenLayers.Feature.Vector>})} |
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467 | * options - {Object} Object whose possible keys are "create", "update", |
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468 | * "delete", "callback" and "scope", the values referenced by the |
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469 | * first three are objects as passed to the "create", "update", and |
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470 | * "delete" methods, the value referenced by the "callback" key is |
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471 | * a function which is called when the commit operation is complete |
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472 | * using the scope referenced by the "scope" key. |
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473 | * |
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474 | * Returns: |
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475 | * {Array({<OpenLayers.Protocol.Response>})} An array of |
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476 | * <OpenLayers.Protocol.Response> objects, one per request made |
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477 | * to the database. |
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478 | */ |
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479 | commit: function(features, options) { |
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480 | var opt, resp = [], nRequests = 0, nResponses = 0; |
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481 | |
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482 | function callback(resp) { |
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483 | if (++nResponses < nRequests) { |
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484 | resp.last = false; |
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485 | } |
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486 | this.callUserCallback(options, resp); |
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487 | } |
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488 | |
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489 | var feature, toCreate = [], toUpdate = [], toDelete = []; |
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490 | for (var i = features.length - 1; i >= 0; i--) { |
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491 | feature = features[i]; |
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492 | switch (feature.state) { |
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493 | case OpenLayers.State.INSERT: |
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494 | toCreate.push(feature); |
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495 | break; |
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496 | case OpenLayers.State.UPDATE: |
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497 | toUpdate.push(feature); |
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498 | break; |
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499 | case OpenLayers.State.DELETE: |
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500 | toDelete.push(feature); |
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501 | break; |
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502 | } |
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503 | } |
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504 | if (toCreate.length > 0) { |
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505 | nRequests++; |
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506 | opt = OpenLayers.Util.applyDefaults( |
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507 | {"callback": callback, "scope": this}, |
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508 | options.create |
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509 | ); |
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510 | resp.push(this.create(toCreate, opt)); |
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511 | } |
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512 | if (toUpdate.length > 0) { |
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513 | nRequests++; |
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514 | opt = OpenLayers.Util.applyDefaults( |
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515 | {"callback": callback, "scope": this}, |
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516 | options.update |
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517 | ); |
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518 | resp.push(this.update(toUpdate, opt)); |
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519 | } |
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520 | if (toDelete.length > 0) { |
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521 | nRequests++; |
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522 | opt = OpenLayers.Util.applyDefaults( |
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523 | {"callback": callback, "scope": this}, |
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524 | options["delete"] |
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525 | ); |
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526 | resp.push(this["delete"](toDelete, opt)); |
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527 | } |
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528 | |
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529 | return resp; |
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530 | }, |
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531 | |
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532 | /** |
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533 | * Method: clear |
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534 | * Removes all rows of the table. |
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535 | */ |
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536 | clear: function() { |
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537 | this.db.execute("DELETE FROM " + this.tableName); |
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538 | }, |
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539 | |
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540 | /** |
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541 | * Method: callUserCallback |
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542 | * This method is called from within commit each time a request is made |
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543 | * to the database, it is responsible for calling the user-supplied |
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544 | * callbacks. |
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545 | * |
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546 | * Parameters: |
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547 | * options - {Object} The map of options passed to the commit call. |
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548 | * resp - {<OpenLayers.Protocol.Response>} |
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549 | */ |
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550 | callUserCallback: function(options, resp) { |
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551 | var opt = options[resp.requestType]; |
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552 | if (opt && opt.callback) { |
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553 | opt.callback.call(opt.scope, resp); |
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554 | } |
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555 | if (resp.last && options.callback) { |
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556 | options.callback.call(options.scope); |
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557 | } |
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558 | }, |
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559 | |
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560 | CLASS_NAME: "OpenLayers.Protocol.SQL.Gears" |
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561 | }); |
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