colonymech / docs / www / colonyscout / internal / includes / uploadify / com / adobe / serialization / json / JSONEncoder.as @ f59acf11
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1 | f59acf11 | Dan Shope | /* |
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2 | Copyright (c) 2008, Adobe Systems Incorporated |
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3 | All rights reserved. |
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4 | |||
5 | Redistribution and use in source and binary forms, with or without |
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6 | modification, are permitted provided that the following conditions are |
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7 | met: |
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8 | |||
9 | * Redistributions of source code must retain the above copyright notice, |
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10 | this list of conditions and the following disclaimer. |
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11 | |||
12 | * Redistributions in binary form must reproduce the above copyright |
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13 | notice, this list of conditions and the following disclaimer in the |
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14 | documentation and/or other materials provided with the distribution. |
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15 | |||
16 | * Neither the name of Adobe Systems Incorporated nor the names of its |
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17 | contributors may be used to endorse or promote products derived from |
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18 | this software without specific prior written permission. |
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19 | |||
20 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS |
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21 | IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, |
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22 | THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
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23 | PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
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24 | CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
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25 | EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
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26 | PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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27 | PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
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28 | LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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29 | NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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30 | SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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31 | */ |
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32 | |||
33 | package com.adobe.serialization.json |
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34 | { |
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35 | |||
36 | import flash.utils.describeType; |
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37 | |||
38 | public class JSONEncoder { |
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39 | |||
40 | /** The string that is going to represent the object we're encoding */ |
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41 | private var jsonString:String; |
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42 | |||
43 | /** |
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44 | * Creates a new JSONEncoder. |
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45 | * |
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46 | * @param o The object to encode as a JSON string |
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47 | * @langversion ActionScript 3.0 |
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48 | * @playerversion Flash 9.0 |
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49 | * @tiptext |
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50 | */ |
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51 | public function JSONEncoder( value:* ) { |
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52 | jsonString = convertToString( value ); |
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53 | |||
54 | } |
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55 | |||
56 | /** |
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57 | * Gets the JSON string from the encoder. |
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58 | * |
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59 | * @return The JSON string representation of the object |
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60 | * that was passed to the constructor |
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61 | * @langversion ActionScript 3.0 |
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62 | * @playerversion Flash 9.0 |
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63 | * @tiptext |
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64 | */ |
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65 | public function getString():String { |
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66 | return jsonString; |
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67 | } |
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68 | |||
69 | /** |
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70 | * Converts a value to it's JSON string equivalent. |
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71 | * |
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72 | * @param value The value to convert. Could be any |
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73 | * type (object, number, array, etc) |
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74 | */ |
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75 | private function convertToString( value:* ):String { |
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76 | |||
77 | // determine what value is and convert it based on it's type |
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78 | if ( value is String ) { |
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79 | |||
80 | // escape the string so it's formatted correctly |
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81 | return escapeString( value as String ); |
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82 | |||
83 | } else if ( value is Number ) { |
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84 | |||
85 | // only encode numbers that finate |
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86 | return isFinite( value as Number) ? value.toString() : "null"; |
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87 | |||
88 | } else if ( value is Boolean ) { |
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89 | |||
90 | // convert boolean to string easily |
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91 | return value ? "true" : "false"; |
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92 | |||
93 | } else if ( value is Array ) { |
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94 | |||
95 | // call the helper method to convert an array |
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96 | return arrayToString( value as Array ); |
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97 | |||
98 | } else if ( value is Object && value != null ) { |
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99 | |||
100 | // call the helper method to convert an object |
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101 | return objectToString( value ); |
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102 | } |
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103 | return "null"; |
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104 | } |
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105 | |||
106 | /** |
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107 | * Escapes a string accoding to the JSON specification. |
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108 | * |
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109 | * @param str The string to be escaped |
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110 | * @return The string with escaped special characters |
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111 | * according to the JSON specification |
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112 | */ |
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113 | private function escapeString( str:String ):String { |
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114 | // create a string to store the string's jsonstring value |
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115 | var s:String = ""; |
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116 | // current character in the string we're processing |
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117 | var ch:String; |
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118 | // store the length in a local variable to reduce lookups |
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119 | var len:Number = str.length; |
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120 | |||
121 | // loop over all of the characters in the string |
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122 | for ( var i:int = 0; i < len; i++ ) { |
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123 | |||
124 | // examine the character to determine if we have to escape it |
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125 | ch = str.charAt( i ); |
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126 | switch ( ch ) { |
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127 | |||
128 | case '"': // quotation mark |
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129 | s += "\\\""; |
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130 | break; |
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131 | |||
132 | //case '/': // solidus |
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133 | // s += "\\/"; |
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134 | // break; |
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135 | |||
136 | case '\\': // reverse solidus |
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137 | s += "\\\\"; |
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138 | break; |
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139 | |||
140 | case '\b': // bell |
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141 | s += "\\b"; |
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142 | break; |
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143 | |||
144 | case '\f': // form feed |
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145 | s += "\\f"; |
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146 | break; |
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147 | |||
148 | case '\n': // newline |
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149 | s += "\\n"; |
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150 | break; |
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151 | |||
152 | case '\r': // carriage return |
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153 | s += "\\r"; |
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154 | break; |
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155 | |||
156 | case '\t': // horizontal tab |
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157 | s += "\\t"; |
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158 | break; |
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159 | |||
160 | default: // everything else |
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161 | |||
162 | // check for a control character and escape as unicode |
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163 | if ( ch < ' ' ) { |
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164 | // get the hex digit(s) of the character (either 1 or 2 digits) |
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165 | var hexCode:String = ch.charCodeAt( 0 ).toString( 16 ); |
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166 | |||
167 | // ensure that there are 4 digits by adjusting |
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168 | // the # of zeros accordingly. |
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169 | var zeroPad:String = hexCode.length == 2 ? "00" : "000"; |
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170 | |||
171 | // create the unicode escape sequence with 4 hex digits |
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172 | s += "\\u" + zeroPad + hexCode; |
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173 | } else { |
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174 | |||
175 | // no need to do any special encoding, just pass-through |
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176 | s += ch; |
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177 | |||
178 | } |
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179 | } // end switch |
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180 | |||
181 | } // end for loop |
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182 | |||
183 | return "\"" + s + "\""; |
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184 | } |
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185 | |||
186 | /** |
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187 | * Converts an array to it's JSON string equivalent |
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188 | * |
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189 | * @param a The array to convert |
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190 | * @return The JSON string representation of <code>a</code> |
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191 | */ |
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192 | private function arrayToString( a:Array ):String { |
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193 | // create a string to store the array's jsonstring value |
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194 | var s:String = ""; |
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195 | |||
196 | // loop over the elements in the array and add their converted |
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197 | // values to the string |
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198 | for ( var i:int = 0; i < a.length; i++ ) { |
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199 | // when the length is 0 we're adding the first element so |
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200 | // no comma is necessary |
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201 | if ( s.length > 0 ) { |
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202 | // we've already added an element, so add the comma separator |
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203 | s += "," |
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204 | } |
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205 | |||
206 | // convert the value to a string |
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207 | s += convertToString( a[i] ); |
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208 | } |
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209 | |||
210 | // KNOWN ISSUE: In ActionScript, Arrays can also be associative |
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211 | // objects and you can put anything in them, ie: |
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212 | // myArray["foo"] = "bar"; |
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213 | // |
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214 | // These properties aren't picked up in the for loop above because |
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215 | // the properties don't correspond to indexes. However, we're |
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216 | // sort of out luck because the JSON specification doesn't allow |
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217 | // these types of array properties. |
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218 | // |
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219 | // So, if the array was also used as an associative object, there |
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220 | // may be some values in the array that don't get properly encoded. |
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221 | // |
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222 | // A possible solution is to instead encode the Array as an Object |
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223 | // but then it won't get decoded correctly (and won't be an |
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224 | // Array instance) |
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225 | |||
226 | // close the array and return it's string value |
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227 | return "[" + s + "]"; |
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228 | } |
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229 | |||
230 | /** |
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231 | * Converts an object to it's JSON string equivalent |
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232 | * |
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233 | * @param o The object to convert |
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234 | * @return The JSON string representation of <code>o</code> |
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235 | */ |
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236 | private function objectToString( o:Object ):String |
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237 | { |
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238 | // create a string to store the object's jsonstring value |
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239 | var s:String = ""; |
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240 | |||
241 | // determine if o is a class instance or a plain object |
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242 | var classInfo:XML = describeType( o ); |
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243 | if ( classInfo.@name.toString() == "Object" ) |
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244 | { |
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245 | // the value of o[key] in the loop below - store this |
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246 | // as a variable so we don't have to keep looking up o[key] |
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247 | // when testing for valid values to convert |
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248 | var value:Object; |
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249 | |||
250 | // loop over the keys in the object and add their converted |
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251 | // values to the string |
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252 | for ( var key:String in o ) |
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253 | { |
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254 | // assign value to a variable for quick lookup |
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255 | value = o[key]; |
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256 | |||
257 | // don't add function's to the JSON string |
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258 | if ( value is Function ) |
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259 | { |
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260 | // skip this key and try another |
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261 | continue; |
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262 | } |
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263 | |||
264 | // when the length is 0 we're adding the first item so |
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265 | // no comma is necessary |
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266 | if ( s.length > 0 ) { |
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267 | // we've already added an item, so add the comma separator |
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268 | s += "," |
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269 | } |
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270 | |||
271 | s += escapeString( key ) + ":" + convertToString( value ); |
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272 | } |
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273 | } |
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274 | else // o is a class instance |
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275 | { |
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276 | // Loop over all of the variables and accessors in the class and |
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277 | // serialize them along with their values. |
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278 | for each ( var v:XML in classInfo..*.( name() == "variable" || name() == "accessor" ) ) |
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279 | { |
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280 | // When the length is 0 we're adding the first item so |
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281 | // no comma is necessary |
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282 | if ( s.length > 0 ) { |
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283 | // We've already added an item, so add the comma separator |
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284 | s += "," |
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285 | } |
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286 | |||
287 | s += escapeString( v.@name.toString() ) + ":" |
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288 | + convertToString( o[ v.@name ] ); |
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289 | } |
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290 | |||
291 | } |
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292 | |||
293 | return "{" + s + "}"; |
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294 | } |
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295 | |||
296 | |||
297 | } |
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298 | |||
299 | } |