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Rev | Author | Line No. | Line |
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956 | dev | 1 | package ak.backpath; |
2 | |||
3 | import java.io.InputStream; |
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4 | import java.io.OutputStream; |
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5 | import java.io.ByteArrayInputStream; |
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6 | import java.io.ByteArrayOutputStream; |
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7 | import java.io.IOException; |
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8 | import java.util.Arrays; |
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9 | import java.util.List; |
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10 | import java.util.Iterator; |
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11 | import java.util.Map; |
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12 | import java.util.ArrayList; |
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13 | import java.util.Set; |
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14 | import java.util.TreeSet; |
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15 | import java.util.Collections; |
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16 | import java.util.zip.Deflater; |
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17 | import java.util.zip.Inflater; |
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18 | import java.util.zip.DeflaterOutputStream; |
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19 | import java.util.zip.InflaterInputStream; |
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20 | import java.net.URL; |
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21 | import java.net.URLEncoder; |
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22 | import javax.servlet.http.HttpServletRequest; |
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23 | import org.apache.commons.logging.Log; |
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24 | import org.apache.commons.logging.LogFactory; |
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25 | |||
26 | public class BackPath |
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27 | { |
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28 | private static Log log = LogFactory.getLog(BackPath.class); |
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29 | |||
30 | public static final String DEFAULT_KEY = BackPath.class.getName(); |
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31 | public static final String DEFAULT_PARAM = "backpath"; |
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32 | public static final String OUT_CHARSET = "UTF-8"; |
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33 | public static final String URL_CHARSET = "UTF-8"; |
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34 | public static final String IGNORES_DELIMITER = "\\s*;\\s*"; |
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35 | public static final boolean DEFAULT_ZIP = true; |
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36 | public static final String[] METHODS_TO_SAVE_PARAMS = {"GET"}; |
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37 | public static final char URL_PARAM_START = '?'; |
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999 | dev | 38 | public static final char URL_PARAM_SEPARATOR = '&'; |
956 | dev | 39 | public static final char URL_PARAM_VALUE = '='; |
40 | public static final char URL_PARAM_VALUE_SEP = ','; |
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41 | |||
42 | protected static final byte URL_DELIMITER = 0; |
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43 | protected static final int BUFFER_SIZE = 1024; |
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44 | protected static final int INIT_STREAM_SIZE_COEF = 100; |
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45 | protected static final String URL_PARAM_START_STR = "" + URL_PARAM_START; |
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46 | |||
47 | protected static Set methodsToSaveParams; |
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48 | |||
49 | // List(String) |
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50 | protected List stack = new ArrayList(); |
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51 | protected String param = DEFAULT_PARAM; |
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52 | protected String[] ignoreParams = null; |
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53 | |||
54 | /** zip the stack */ |
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55 | protected boolean zip = DEFAULT_ZIP; |
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56 | |||
57 | // string cache |
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58 | protected String forwardParams; |
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59 | protected boolean forwardParamsFormed = false; |
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60 | protected String currentParams; |
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61 | protected boolean currentParamsFormed = false; |
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1026 | dev | 62 | protected String currentUrl; |
63 | protected boolean currentUrlFormed = false; |
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956 | dev | 64 | protected String backwardParams; |
65 | protected boolean backwardParamsFormed = false; |
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66 | protected String backwardUrl; |
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67 | protected boolean backwardUrlFormed = false; |
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68 | |||
69 | static { |
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70 | methodsToSaveParams = Collections.unmodifiableSet( |
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71 | new TreeSet(Arrays.asList(METHODS_TO_SAVE_PARAMS))); |
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72 | } |
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73 | |||
74 | protected static Deflater deflater = new Deflater(); |
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75 | protected static Inflater inflater = new Inflater(); |
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76 | |||
77 | public static BackPath findBackPath(HttpServletRequest request) |
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78 | throws Exception |
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79 | { |
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80 | return findBackPath(request, DEFAULT_KEY, DEFAULT_PARAM, (String)null, DEFAULT_ZIP); |
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81 | } |
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82 | |||
83 | public static BackPath findBackPath(HttpServletRequest request, String backPathKey, |
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84 | String backPathParam, String backPathIgnore, boolean zip) |
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85 | throws Exception |
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86 | { |
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1026 | dev | 87 | String[] ignores = null; |
88 | |||
89 | if(backPathIgnore != null) |
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90 | ignores = backPathIgnore.trim().split(IGNORES_DELIMITER); |
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91 | |||
92 | return findBackPath(request, backPathKey, backPathParam, ignores, zip); |
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93 | } |
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94 | |||
95 | public static BackPath findBackPath(HttpServletRequest request, String backPathKey, |
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96 | String backPathParam, String[] ignores, boolean zip) |
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97 | throws Exception |
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98 | { |
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956 | dev | 99 | Object backPathObj = request.getAttribute(backPathKey); |
100 | |||
101 | if(backPathObj == null) { |
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102 | BackPath backPath; |
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103 | |||
104 | backPath = new BackPath(request, backPathParam, ignores, zip); |
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105 | request.setAttribute(backPathKey, backPath); |
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106 | return backPath; |
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107 | } |
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108 | else if(backPathObj instanceof BackPath) { |
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109 | return (BackPath)backPathObj; |
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110 | } |
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111 | else { |
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112 | throw new Exception("An object under key " + backPathKey |
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113 | + " is not a " + BackPath.class.getName()); |
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114 | } |
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115 | } |
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116 | |||
117 | public BackPath(HttpServletRequest request, String param, String[] ignoreParams, boolean zip) |
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118 | { |
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119 | this.zip = zip; |
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120 | this.param = param; |
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121 | this.ignoreParams = ignoreParams; |
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122 | init(request); |
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123 | } |
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124 | |||
125 | public boolean getZip() |
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126 | { |
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127 | return zip; |
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128 | } |
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129 | |||
130 | public void setZip(boolean zip) |
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131 | { |
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132 | this.zip = zip; |
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133 | resetCachedStrings(); |
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134 | } |
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135 | |||
136 | public String getParam() |
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137 | { |
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138 | return param; |
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139 | } |
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140 | |||
141 | public void setParam(String param) |
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142 | { |
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143 | this.param = param; |
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144 | resetCachedStrings(); |
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145 | } |
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146 | |||
147 | public String[] getIgnoreParams() |
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148 | { |
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149 | return ignoreParams; |
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150 | } |
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151 | |||
152 | public void setIgnoreParams(String[] ignoreParams) |
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153 | { |
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154 | this.ignoreParams = ignoreParams; |
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155 | resetCachedStrings(); |
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156 | } |
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157 | |||
158 | public boolean getHasBack() |
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159 | { |
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160 | return (stack.size() > 1); |
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161 | } |
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162 | |||
163 | // List(String) |
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164 | public List getStack() |
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165 | { |
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166 | return Collections.unmodifiableList(stack); |
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167 | } |
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168 | |||
169 | public String getForwardParams() |
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170 | { |
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171 | if(!forwardParamsFormed) { |
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172 | forwardParams = formForwardParams(); |
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173 | forwardParamsFormed = true; |
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174 | } |
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175 | |||
176 | return forwardParams; |
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177 | } |
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178 | |||
179 | protected String formForwardParams() |
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180 | { |
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181 | try { |
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182 | return encode(stack, zip, 0); |
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183 | } |
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184 | catch(IOException ex) { |
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185 | log.error("Cannot form forward params", ex); |
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186 | return null; |
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187 | } |
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188 | } |
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189 | |||
190 | public String getBackwardParams() |
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191 | { |
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192 | if(!backwardParamsFormed) { |
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193 | backwardParams = formBackwardParams(); |
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194 | backwardParamsFormed = true; |
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195 | } |
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196 | |||
197 | return backwardParams; |
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198 | } |
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199 | |||
200 | protected String formBackwardParams() |
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201 | { |
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202 | try { |
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203 | if(stack.size() <= 2) |
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204 | return null; |
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205 | else |
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206 | return encode(stack, zip, 2); |
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207 | } |
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208 | catch(IOException ex) { |
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209 | log.error("Cannot form backward params", ex); |
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210 | return null; |
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211 | } |
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212 | } |
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213 | |||
214 | public String getBackwardUrl() |
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215 | { |
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216 | if(!backwardParamsFormed) { |
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217 | backwardUrl = formBackwardUrl(); |
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218 | backwardUrlFormed = true; |
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219 | } |
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220 | |||
221 | return backwardUrl; |
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222 | } |
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223 | |||
224 | protected String formBackwardUrl() |
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225 | { |
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226 | if(stack.size() < 2) return null; |
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227 | |||
228 | try { |
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229 | StringBuffer url = new StringBuffer((String)stack.get(stack.size()-2)); |
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230 | if(stack.size() > 2) { |
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231 | String s = encode(stack, zip, 2); |
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232 | if(url.indexOf(URL_PARAM_START_STR) >= 0) url.append(URL_PARAM_SEPARATOR); |
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233 | else url.append(URL_PARAM_START); |
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234 | url.append(param).append(URL_PARAM_VALUE).append(s); |
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235 | } |
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236 | |||
237 | return url.toString(); |
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238 | } |
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239 | catch(IOException ex) { |
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240 | log.error("Cannot form backward url", ex); |
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241 | return null; |
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242 | } |
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243 | } |
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244 | |||
245 | public String getCurrentParams() |
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246 | { |
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247 | if(!currentParamsFormed) { |
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248 | currentParams = formCurrentParams(); |
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249 | currentParamsFormed = true; |
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250 | } |
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251 | |||
252 | return currentParams; |
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253 | } |
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254 | |||
255 | protected String formCurrentParams() |
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256 | { |
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257 | try { |
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258 | if(stack.size() <= 1) |
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259 | return null; |
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260 | else |
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261 | return encode(stack, zip, 1); |
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262 | } |
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263 | catch(IOException ex) { |
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264 | log.error("Cannot form current params", ex); |
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265 | return null; |
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266 | } |
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267 | } |
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268 | |||
1026 | dev | 269 | public String getCurrentUrl() |
270 | { |
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271 | if(!currentParamsFormed) { |
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272 | currentUrl = formCurrentUrl(); |
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273 | currentUrlFormed = true; |
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274 | } |
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275 | |||
276 | return currentUrl; |
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277 | } |
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278 | |||
279 | protected String formCurrentUrl() |
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280 | { |
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281 | if(stack.size() < 1) return null; |
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282 | |||
283 | try { |
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284 | StringBuffer url = new StringBuffer((String)stack.get(stack.size()-1)); |
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285 | if(stack.size() > 1) { |
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286 | String s = encode(stack, zip, 1); |
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287 | if(url.indexOf(URL_PARAM_START_STR) >= 0) url.append(URL_PARAM_SEPARATOR); |
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288 | else url.append(URL_PARAM_START); |
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289 | url.append(param).append(URL_PARAM_VALUE).append(s); |
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290 | } |
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291 | |||
292 | return url.toString(); |
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293 | } |
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294 | catch(IOException ex) { |
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295 | log.error("Cannot form current url", ex); |
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296 | return null; |
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297 | } |
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298 | } |
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299 | |||
956 | dev | 300 | public void init(HttpServletRequest request) |
301 | { |
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302 | try { |
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303 | resetCachedStrings(); |
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304 | // get old |
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305 | decode(stack, request.getParameter(param), zip); |
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306 | |||
307 | // add new |
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308 | String url = (new URL(request.getRequestURL().toString())).getPath(); |
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309 | if(methodsToSaveParams.contains(request.getMethod())) { |
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310 | // to ignore |
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311 | Set ignore = new TreeSet(); |
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312 | if(ignoreParams != null) { |
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313 | for(int i = 0; i < ignoreParams.length; i++) |
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314 | ignore.add(ignoreParams[i]); |
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315 | } |
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316 | ignore.add(param); |
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317 | |||
318 | // form query string |
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319 | StringBuffer query = new StringBuffer(); |
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320 | Map requestParams = request.getParameterMap(); |
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321 | for(Iterator i = requestParams.keySet().iterator(); i.hasNext(); ) { |
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322 | String name = (String)i.next(); |
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323 | if(ignore.contains(name)) continue; |
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324 | if(query.length() == 0) |
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325 | query.append(URL_PARAM_START); |
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326 | else |
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327 | query.append(URL_PARAM_SEPARATOR); |
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328 | |||
329 | query.append(URLEncoder.encode(name, URL_CHARSET)); |
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330 | query.append(URL_PARAM_VALUE); |
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331 | String[] values = (String[])requestParams.get(name); |
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332 | for(int j = 0; j < values.length; j++) { |
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333 | if(j > 0) query.append(URL_PARAM_VALUE_SEP); |
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334 | query.append(URLEncoder.encode(values[j], URL_CHARSET)); |
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335 | } |
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336 | } |
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337 | |||
338 | // form url |
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339 | if(query.length() > 0) url = query.insert(0, url).toString(); |
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340 | } |
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1026 | dev | 341 | |
956 | dev | 342 | stack.add(url); |
343 | } |
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344 | catch(IOException ex) { |
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345 | log.error("Cannot init", ex); |
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346 | } |
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347 | } |
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348 | |||
349 | /** |
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350 | * @param stack List(String) |
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351 | */ |
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352 | protected String encode(List stack, boolean zip, int suffix) |
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353 | throws IOException |
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354 | { |
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355 | ByteArrayOutputStream buf = new ByteArrayOutputStream(stack.size()*INIT_STREAM_SIZE_COEF); |
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356 | Object lock = (zip ? (Object)BackPath.class : this); |
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357 | |||
358 | synchronized(lock) { |
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359 | OutputStream out; |
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360 | if(zip) { |
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361 | deflater.reset(); |
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362 | out = new DeflaterOutputStream(new Base64.OutputStream(buf), deflater); |
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363 | } |
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364 | else { |
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365 | out = new Base64.OutputStream(buf); |
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366 | } |
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367 | |||
368 | for(int i = 0; i < stack.size()-suffix; i++) { |
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369 | String s = (String)stack.get(i); |
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370 | if(i > 0) out.write(URL_DELIMITER); |
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371 | out.write(s.getBytes(URL_CHARSET)); |
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372 | } |
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373 | out.close(); |
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374 | } |
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375 | |||
376 | return buf.toString(OUT_CHARSET); |
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377 | } |
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378 | |||
379 | /** |
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380 | * @param stack List(String) |
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381 | */ |
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382 | protected void decode(List stack, String path, boolean zip) |
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383 | throws IOException |
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384 | { |
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385 | stack.clear(); |
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386 | if(path == null || path.equals("")) return; |
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387 | |||
388 | ByteArrayOutputStream dec = new ByteArrayOutputStream(stack.size()*INIT_STREAM_SIZE_COEF); |
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389 | Object lock = (zip ? (Object)BackPath.class : this); |
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390 | |||
391 | synchronized(lock) { |
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392 | ByteArrayInputStream enc = new ByteArrayInputStream(path.getBytes(OUT_CHARSET)); |
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393 | |||
394 | InputStream in; |
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395 | if(zip) { |
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396 | inflater.reset(); |
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397 | in = new InflaterInputStream(new Base64.InputStream(enc), inflater); |
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398 | } |
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399 | else { |
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400 | in = new Base64.InputStream(enc); |
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401 | } |
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402 | |||
403 | byte[] tmp = new byte[BUFFER_SIZE]; |
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404 | int l; |
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405 | while((l = in.read(tmp, 0, tmp.length)) > 0) { |
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406 | dec.write(tmp, 0, l); |
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407 | } |
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408 | } |
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409 | |||
410 | try { |
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411 | byte[] buf = dec.toByteArray(); |
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412 | for(int start = 0, end = 0; end <= buf.length; end++) { |
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413 | if(end == buf.length || buf[end] == URL_DELIMITER) { |
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414 | stack.add(new String(buf, start, end-start, URL_CHARSET)); |
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415 | start = end+1; |
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416 | } |
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417 | } |
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418 | } |
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419 | catch(Exception ex) { // if some mistake in stack, then ignore it completely |
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420 | stack.clear(); |
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421 | log.info("Cannot parse stack", ex); |
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422 | } |
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423 | } |
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424 | |||
425 | protected void resetCachedStrings() |
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426 | { |
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427 | forwardParams = null; |
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428 | forwardParamsFormed = false; |
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429 | currentParams = null; |
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430 | currentParamsFormed = false; |
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1026 | dev | 431 | currentUrl = null; |
432 | currentUrlFormed = false; |
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956 | dev | 433 | backwardParams = null; |
434 | backwardParamsFormed = false; |
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435 | backwardUrl = null; |
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436 | backwardUrlFormed = false; |
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437 | } |
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438 | } |