[857] | 1 | package de.ugoe.cs.autoquest.htmlmonitor; |
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| 2 | |
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| 3 | import java.io.IOException; |
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| 4 | import java.io.InputStreamReader; |
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| 5 | import java.net.MalformedURLException; |
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| 6 | import java.net.URL; |
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| 7 | import java.util.ArrayList; |
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| 8 | import java.util.List; |
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| 9 | import java.util.Map; |
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| 10 | import java.util.Set; |
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| 11 | |
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| 12 | import javax.servlet.ServletException; |
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| 13 | import javax.servlet.http.HttpServletRequest; |
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| 14 | import javax.servlet.http.HttpServletResponse; |
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| 15 | |
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| 16 | import org.json.simple.JSONArray; |
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| 17 | import org.json.simple.JSONObject; |
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| 18 | import org.json.simple.JSONValue; |
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| 19 | import org.json.simple.parser.ParseException; |
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| 20 | import org.mortbay.jetty.servlet.DefaultServlet; |
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| 21 | |
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| 22 | import de.ugoe.cs.util.console.Console; |
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| 23 | |
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| 24 | /** |
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| 25 | * <p> |
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[871] | 26 | * the servlet deployed in the web server that receives all client messages. The messages are |
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| 27 | * parsed, validated, and forwarded to the provided message listener. If a message is not valid, |
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| 28 | * it is discarded. If an event in a message is not valid, it is discarded. Messages are only |
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| 29 | * received via the POST HTTP method. |
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[857] | 30 | * </p> |
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| 31 | * |
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| 32 | * @author Patrick Harms |
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| 33 | */ |
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[871] | 34 | class HtmlMonitorServlet extends DefaultServlet { |
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[857] | 35 | |
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| 36 | /** */ |
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| 37 | private static final long serialVersionUID = 1L; |
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| 38 | |
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| 39 | /** |
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[871] | 40 | * the message listener to forward received messages to. |
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[857] | 41 | */ |
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| 42 | private HtmlMonitorMessageListener messageListener; |
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| 43 | |
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| 44 | /** |
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| 45 | * <p> |
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[871] | 46 | * initializes the servlet with the message listener to which all events shall be forwarded |
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[857] | 47 | * </p> |
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| 48 | * |
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[871] | 49 | * @param messageListener the message listener that shall receive all client events |
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[857] | 50 | */ |
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| 51 | HtmlMonitorServlet(HtmlMonitorMessageListener messageListener) { |
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| 52 | this.messageListener = messageListener; |
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| 53 | } |
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| 54 | |
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| 55 | /* (non-Javadoc) |
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| 56 | * @see org.mortbay.jetty.servlet.DefaultServlet#doPost(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) |
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| 57 | */ |
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| 58 | @Override |
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| 59 | protected void doPost(HttpServletRequest request, HttpServletResponse response) |
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| 60 | throws ServletException, IOException |
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| 61 | { |
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| 62 | Object value = null; |
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| 63 | try { |
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| 64 | value = JSONValue.parseWithException(new InputStreamReader(request.getInputStream())); |
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| 65 | |
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| 66 | if (!(value instanceof JSONObject)) { |
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| 67 | Console.printerrln("incoming data is not of the expected type --> discarding it"); |
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| 68 | } |
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| 69 | else { |
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| 70 | handleJSONObject((JSONObject) value); |
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| 71 | } |
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| 72 | } |
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| 73 | catch (ParseException e) { |
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| 74 | Console.printerrln |
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| 75 | ("could not parse incoming data --> discarding it (" + e.toString() + ")"); |
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| 76 | } |
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| 77 | } |
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| 78 | |
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| 79 | /** |
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| 80 | * <p> |
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[871] | 81 | * processes a received JSON object and validates it. If the message is ok, it is forwarded |
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| 82 | * to the message listener |
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[857] | 83 | * </p> |
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| 84 | * |
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[871] | 85 | * @param object the JSON object that contains a client message |
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[857] | 86 | */ |
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| 87 | private void handleJSONObject(JSONObject object) { |
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| 88 | dumpJSONObject(object, ""); |
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| 89 | |
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| 90 | JSONObject message = assertValue(object, "message", JSONObject.class); |
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| 91 | |
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| 92 | if (message == null) { |
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| 93 | Console.printerrln("incoming data is no valid message --> discarding it"); |
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| 94 | } |
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| 95 | else { |
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| 96 | HtmlClientInfos clientInfos = extractClientInfos(message); |
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| 97 | |
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| 98 | if (clientInfos == null) { |
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| 99 | Console.printerrln |
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| 100 | ("incoming message does not contain valid client infos --> discarding it"); |
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| 101 | } |
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| 102 | else { |
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| 103 | HtmlEvent[] events = extractHtmlEvents(message, clientInfos); |
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| 104 | if (events == null) { |
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| 105 | Console.printerrln |
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| 106 | ("incoming message does not contain valid events --> discarding it"); |
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| 107 | } |
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| 108 | else { |
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| 109 | messageListener.handleMessage(clientInfos, events); |
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| 110 | } |
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| 111 | } |
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| 112 | } |
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| 113 | } |
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| 114 | |
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| 115 | /** |
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| 116 | * <p> |
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[871] | 117 | * tries to extract the client infos out of the received JSON object. If this is not fully |
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| 118 | * possible, an appropriate message is dumped and the whole message is discarded (the method |
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| 119 | * return null). |
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[857] | 120 | * </p> |
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| 121 | * |
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[871] | 122 | * @param message the message to parse the client infos from |
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| 123 | * |
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| 124 | * @return the client infos, if the message is valid in this respect, or null if not |
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[857] | 125 | */ |
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| 126 | private HtmlClientInfos extractClientInfos(JSONObject message) { |
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| 127 | HtmlClientInfos clientInfos = null; |
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| 128 | |
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| 129 | JSONObject infos = assertValue(message, "clientInfos", JSONObject.class); |
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| 130 | |
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| 131 | if (infos != null) { |
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| 132 | String clientId = assertValue((JSONObject) infos, "clientId", String.class); |
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| 133 | String userAgent = assertValue((JSONObject) infos, "userAgent", String.class); |
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| 134 | URL url = assertValue((JSONObject) infos, "url", URL.class); |
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| 135 | String title = assertValue((JSONObject) infos, "title", String.class); |
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| 136 | |
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| 137 | if (clientId == null) { |
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| 138 | Console.printerrln("client infos do not contain a valid client id"); |
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| 139 | } |
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| 140 | else if (userAgent == null) { |
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| 141 | Console.printerrln("client infos do not contain a valid user agent"); |
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| 142 | } |
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| 143 | else if (url == null) { |
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| 144 | Console.printerrln("client infos do not contain a valid URL"); |
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| 145 | } |
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| 146 | else if (title == null) { |
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| 147 | Console.printerrln("client infos do not contain a valid title"); |
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| 148 | } |
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| 149 | else { |
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| 150 | clientInfos = new HtmlClientInfos(clientId, userAgent, url, title); |
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| 151 | } |
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| 152 | } |
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| 153 | |
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| 154 | return clientInfos; |
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| 155 | } |
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| 156 | |
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| 157 | /** |
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| 158 | * <p> |
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[871] | 159 | * tries to extract the events out of the received JSON object. If this is not fully |
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| 160 | * possible, an appropriate message is dumped and the errorprone event is discarded. If no |
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| 161 | * valid event is found, the whole message is discarded. |
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[857] | 162 | * </p> |
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| 163 | * |
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[871] | 164 | * @param object the message to parse the events from |
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| 165 | * @param clientInfos the infos about the client that send the events |
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| 166 | * |
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| 167 | * @return the valid events stored in the message, or null if there are none |
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[857] | 168 | */ |
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| 169 | private HtmlEvent[] extractHtmlEvents(JSONObject object, HtmlClientInfos clientInfos) { |
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| 170 | List<HtmlEvent> events = null; |
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| 171 | |
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| 172 | JSONArray eventArray = assertValue(object, "events", JSONArray.class); |
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| 173 | |
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| 174 | if (eventArray != null) { |
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| 175 | events = new ArrayList<HtmlEvent>(); |
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| 176 | |
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| 177 | for (int i = 0; i < eventArray.size(); i++) { |
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| 178 | Object eventObj = eventArray.get(i); |
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| 179 | if (!(eventObj instanceof JSONObject)) { |
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| 180 | Console.printerrln("event number " + (i + 1) + " is not a valid event object"); |
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| 181 | } |
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| 182 | else { |
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| 183 | Long time = assertValue(((JSONObject) eventObj), "time", Long.class); |
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| 184 | String path = assertValue(((JSONObject) eventObj), "path", String.class); |
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| 185 | String eventType = |
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| 186 | assertValue(((JSONObject) eventObj), "eventType", String.class); |
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| 187 | Integer[] coordinates = |
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| 188 | assertValue(((JSONObject) eventObj), "coordinates", Integer[].class); |
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| 189 | Integer key = assertValue(((JSONObject) eventObj), "key", Integer.class); |
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| 190 | Integer scrollPosition = |
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| 191 | assertValue(((JSONObject) eventObj), "scrollPosition", Integer.class); |
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| 192 | |
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| 193 | if (time == null) { |
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| 194 | Console.printerrln("event number " + (i + 1) + " has no valid timestamp"); |
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| 195 | } |
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| 196 | else if (path == null) { |
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| 197 | Console.printerrln("event number " + (i + 1) + " has no valid path"); |
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| 198 | } |
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| 199 | else if (eventType == null) { |
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| 200 | Console.printerrln("event number " + (i + 1) + " has no valid event type"); |
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| 201 | } |
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| 202 | else if ((coordinates != null) && (coordinates.length != 2)) { |
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| 203 | Console.printerrln("event number " + (i + 1) + " has no valid coordinates"); |
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| 204 | } |
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| 205 | else if (checkEventParameterCombinations |
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| 206 | (eventType, coordinates, key, scrollPosition)) |
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| 207 | { |
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| 208 | events.add(new HtmlEvent(clientInfos, time, path, eventType, coordinates, |
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| 209 | key, scrollPosition)); |
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| 210 | } |
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| 211 | else { |
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| 212 | Console.printerrln |
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| 213 | ("event number " + (i + 1) + " has no valid parameter combination"); |
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| 214 | } |
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| 215 | } |
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| 216 | } |
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| 217 | |
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| 218 | } |
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| 219 | |
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| 220 | if ((events != null) && (events.size() > 0)) { |
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| 221 | return events.toArray(new HtmlEvent[events.size()]); |
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| 222 | } |
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| 223 | else { |
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| 224 | return null; |
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| 225 | } |
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| 226 | } |
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| 227 | |
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| 228 | /** |
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| 229 | * <p> |
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[871] | 230 | * validates if for the given event type the parameter combination of coordinates, key, and |
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| 231 | * scroll position is valid. As an example, an onclick event should usually not have an |
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| 232 | * associated scroll position. |
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[857] | 233 | * </p> |
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| 234 | * |
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[871] | 235 | * @param eventType the type of the event |
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| 236 | * @param coordinates the coordinates of the event |
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| 237 | * @param key the key of the event |
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| 238 | * @param scrollPosition the scroll position of the event |
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| 239 | * |
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| 240 | * @return true, if the combination of the parameters is valid, false else |
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[857] | 241 | */ |
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| 242 | private boolean checkEventParameterCombinations(String eventType, |
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| 243 | Integer[] coordinates, |
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| 244 | Integer key, |
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| 245 | Integer scrollPosition) |
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| 246 | { |
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| 247 | boolean result = false; |
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| 248 | |
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| 249 | if ("onscroll".equals(eventType)) { |
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| 250 | if ((coordinates == null) && (key == null) && (scrollPosition != null)) { |
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| 251 | result = true; |
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| 252 | } |
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| 253 | else { |
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| 254 | Console.printerrln(eventType + " event has invalid parameters"); |
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| 255 | } |
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| 256 | } |
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| 257 | else if ("onclick".equals(eventType) || "ondblclick".equals(eventType)) { |
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| 258 | if ((coordinates != null) && (key == null) && (scrollPosition == null)) { |
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| 259 | result = true; |
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| 260 | } |
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| 261 | else { |
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| 262 | Console.printerrln(eventType + " event has invalid parameters"); |
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| 263 | } |
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| 264 | } |
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| 265 | else if ("onkeypress".equals(eventType) || "onkeydown".equals(eventType) || |
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| 266 | "onkeyup".equals(eventType)) |
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| 267 | { |
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| 268 | if ((coordinates == null) && (key != null) && (scrollPosition == null)) { |
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| 269 | result = true; |
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| 270 | } |
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| 271 | else { |
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| 272 | Console.printerrln(eventType + " event has invalid parameters"); |
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| 273 | } |
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| 274 | } |
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| 275 | else if ("onfocus".equals(eventType) || "onmouseout".equals(eventType) || |
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| 276 | "onmousemove".equals(eventType) || "onunload".equals(eventType)) |
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| 277 | { |
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| 278 | if ((coordinates == null) && (key == null) && (scrollPosition == null)) { |
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| 279 | result = true; |
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| 280 | } |
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| 281 | else { |
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| 282 | Console.printerrln(eventType + " event has invalid parameters"); |
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| 283 | } |
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| 284 | } |
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| 285 | else { |
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| 286 | Console.printerrln("'" + eventType + "' is not a valid event type"); |
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| 287 | } |
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| 288 | |
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| 289 | return result; |
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| 290 | } |
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| 291 | |
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| 292 | /** |
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| 293 | * <p> |
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[871] | 294 | * converts a value in the provided object matching the provided key to the provided type. If |
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| 295 | * there is no value with the key or if the value can not be transformed to the provided type, |
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| 296 | * the method returns null. |
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[857] | 297 | * </p> |
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| 298 | * |
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[871] | 299 | * @param object the object to read the value from |
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| 300 | * @param key the key of the value |
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| 301 | * @param clazz the type to which the value should be transformed |
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| 302 | * |
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| 303 | * @return the value or null if either the value does not exist or if it can not be transformed |
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| 304 | * to the expected type |
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[857] | 305 | */ |
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| 306 | @SuppressWarnings("unchecked") |
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| 307 | private <T> T assertValue(JSONObject object, String key, Class<T> clazz) { |
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| 308 | Object value = object.get(key); |
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| 309 | T result = null; |
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| 310 | |
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| 311 | if (clazz.isInstance(value)) { |
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| 312 | result = (T) value; |
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| 313 | } |
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| 314 | else if (value instanceof String) { |
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| 315 | if (URL.class.equals(clazz)) { |
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| 316 | try { |
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| 317 | result = (T) new URL((String) value); |
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| 318 | } |
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| 319 | catch (MalformedURLException e) { |
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| 320 | e.printStackTrace(); |
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| 321 | Console.printerrln("retrieved malformed URL for key '" + key + "': " + value + |
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| 322 | " (" + e.toString() + ")"); |
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| 323 | } |
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| 324 | } |
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| 325 | else if ((int.class.equals(clazz)) || (Integer.class.equals(clazz))) { |
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| 326 | try { |
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| 327 | result = (T) new Integer(Integer.parseInt((String) value)); |
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| 328 | } |
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| 329 | catch (NumberFormatException e) { |
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| 330 | Console.printerrln |
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| 331 | ("retrieved malformed integer for key '" + key + "': " + value); |
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| 332 | } |
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| 333 | } |
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| 334 | else if ((long.class.equals(clazz)) || (Long.class.equals(clazz))) { |
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| 335 | try { |
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| 336 | result = (T) new Long(Long.parseLong((String) value)); |
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| 337 | } |
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| 338 | catch (NumberFormatException e) { |
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| 339 | Console.printerrln |
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| 340 | ("retrieved malformed long for key '" + key + "': " + value); |
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| 341 | } |
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| 342 | } |
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| 343 | } |
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| 344 | else if (value instanceof Long) { |
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| 345 | if ((int.class.equals(clazz)) || (Integer.class.equals(clazz))) { |
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| 346 | result = (T) (Integer) ((Long) value).intValue(); |
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| 347 | } |
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| 348 | } |
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| 349 | else if (value instanceof JSONArray) { |
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| 350 | if ((int[].class.equals(clazz)) || (Integer[].class.equals(clazz))) { |
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| 351 | Integer[] resultArray = new Integer[((JSONArray) value).size()]; |
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| 352 | boolean allCouldBeParsed = true; |
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| 353 | |
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| 354 | for (int i = 0; i < ((JSONArray) value).size(); i++) { |
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| 355 | try { |
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| 356 | if (((JSONArray) value).get(i) instanceof Long) { |
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| 357 | resultArray[i] = (int) (long) (Long) ((JSONArray) value).get(i); |
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| 358 | } |
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| 359 | else if (((JSONArray) value).get(i) instanceof String) { |
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| 360 | try { |
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| 361 | resultArray[i] = |
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| 362 | (int) Long.parseLong((String) ((JSONArray) value).get(i)); |
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| 363 | } |
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| 364 | catch (NumberFormatException e) { |
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| 365 | Console.printerrln |
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| 366 | ("retrieved malformed integer array for key '" + key + "': " + |
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| 367 | value); |
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| 368 | |
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| 369 | allCouldBeParsed = false; |
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| 370 | break; |
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| 371 | } |
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| 372 | } |
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| 373 | else { |
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| 374 | Console.printerrln |
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| 375 | ("can not handle type of value in expected integer array '" + key + |
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| 376 | "': " + value); |
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| 377 | } |
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| 378 | } |
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| 379 | catch (ClassCastException e) { |
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| 380 | e.printStackTrace(); |
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| 381 | Console.printerrln("expected integer array for key '" + key + |
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| 382 | "' but it was something else: " + value); |
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| 383 | |
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| 384 | allCouldBeParsed = false; |
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| 385 | break; |
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| 386 | } |
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| 387 | } |
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| 388 | |
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| 389 | if (allCouldBeParsed) { |
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| 390 | result = (T) resultArray; |
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| 391 | } |
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| 392 | } |
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| 393 | } |
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| 394 | |
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| 395 | return result; |
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| 396 | } |
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| 397 | |
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| 398 | /** |
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| 399 | * <p> |
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[871] | 400 | * convenience method for dumping an object to std out. If the object is a JSON object, it is |
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| 401 | * deeply analyzed and its internal structure is dumped as well. |
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[857] | 402 | * </p> |
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| 403 | * |
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[871] | 404 | * @param object the object to dump |
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| 405 | * @param indent the indentation to be used. |
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[857] | 406 | */ |
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| 407 | private void dumpJSONObject(Object object, String indent) { |
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| 408 | if (object instanceof JSONArray) { |
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| 409 | boolean arrayContainsJSONObjects = false; |
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| 410 | for (Object arrayElem : (JSONArray) object) { |
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| 411 | if (arrayElem instanceof JSONObject) { |
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| 412 | arrayContainsJSONObjects = true; |
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| 413 | break; |
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| 414 | } |
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| 415 | } |
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| 416 | |
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| 417 | if (arrayContainsJSONObjects) { |
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| 418 | System.out.println(); |
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| 419 | System.out.print(indent); |
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| 420 | System.out.println('['); |
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| 421 | System.out.print(indent); |
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| 422 | System.out.print(' '); |
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| 423 | } |
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| 424 | else { |
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| 425 | System.out.print(' '); |
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| 426 | System.out.print('['); |
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| 427 | } |
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| 428 | |
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| 429 | int index = 0; |
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| 430 | for (Object arrayElem : (JSONArray) object) { |
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| 431 | if (index++ > 0) { |
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| 432 | System.out.print(","); |
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| 433 | if (arrayContainsJSONObjects) { |
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| 434 | System.out.println(); |
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| 435 | System.out.print(indent); |
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| 436 | } |
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| 437 | |
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| 438 | System.out.print(' '); |
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| 439 | } |
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| 440 | |
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| 441 | dumpJSONObject(arrayElem, indent + " "); |
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| 442 | } |
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| 443 | |
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| 444 | if (arrayContainsJSONObjects) { |
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| 445 | System.out.println(); |
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| 446 | System.out.print(indent); |
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| 447 | } |
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| 448 | |
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| 449 | System.out.print(']'); |
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| 450 | } |
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| 451 | else if (object instanceof JSONObject) { |
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| 452 | System.out.println(" {"); |
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| 453 | |
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| 454 | @SuppressWarnings("unchecked") |
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| 455 | Set<Map.Entry<?,?>> entrySet = ((JSONObject) object).entrySet(); |
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| 456 | |
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| 457 | int index = 0; |
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| 458 | for (Map.Entry<?,?> entry : entrySet) { |
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| 459 | if (index++ > 0) { |
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| 460 | System.out.println(","); |
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| 461 | } |
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| 462 | System.out.print(indent); |
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| 463 | System.out.print(" \""); |
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| 464 | System.out.print(entry.getKey()); |
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| 465 | System.out.print("\":"); |
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| 466 | dumpJSONObject(entry.getValue(), indent + " "); |
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| 467 | } |
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| 468 | |
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| 469 | System.out.println(); |
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| 470 | System.out.print(indent); |
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| 471 | System.out.print('}'); |
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| 472 | } |
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| 473 | else { |
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| 474 | System.out.print('"'); |
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| 475 | System.out.print(object); |
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| 476 | System.out.print('"'); |
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| 477 | } |
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| 478 | } |
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| 479 | |
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| 480 | } |
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