engine.js

dwr3第一个学习例子

   * A map of all mapped classes whose class declarations have been loaded
   * (dwrClassName -> constructor function)
   * This could have been pre-created by interface scripts, so we need to check.
   */
  if (typeof dwr.engine['_mappedClasses'] == 'undefined') {
    dwr.engine._mappedClasses = {};
  }

  /**
   * Find the HTTP session id sent by the web server
   * @private
   */
  dwr.engine._getHttpSessionId = function() {
    // try to find the httpSessionId
    var cookies = document.cookie.split(';');
    for (var i = 0; i < cookies.length; i++) {
      var cookie = cookies[i];
      while (cookie.charAt(0) == ' ') cookie = cookie.substring(1, cookie.length);
      if (cookie.indexOf(dwr.engine._sessionCookieName + "=") == 0) {
        return cookie.substring(dwr.engine._sessionCookieName.length + 1, cookie.length);
      }
    }
    return "";
  };

  /** A function to call if something fails. */
  dwr.engine._errorHandler = dwr.engine.defaultErrorHandler;

  /** For debugging when something unexplained happens. */
  dwr.engine._warningHandler = dwr.engine.defaultWarningHandler;

  /** Undocumented interceptors - do not use */
  dwr.engine._postSeperator = "\n";
  dwr.engine._defaultInterceptor = function(data) { return data; };
  dwr.engine._urlRewriteHandler = dwr.engine._defaultInterceptor;
  dwr.engine._contentRewriteHandler = dwr.engine._defaultInterceptor;
  dwr.engine._replyRewriteHandler = dwr.engine._defaultInterceptor;

  /** Is this page in the process of unloading? */
  dwr.engine._unloading = false;

  /** @private Abort any XHRs in progress at page unload (solves zombie socket problems in IE). */
  dwr.engine._unloader = function() {
    dwr.engine._unloading = true;

    // Empty queue of waiting ordered requests
    dwr.engine._batchQueue.length = 0;

    // Abort any ongoing XHRs and clear their batches
    var batch;
    for (var batchId in dwr.engine._batches) {
      batch = dwr.engine._batches[batchId];
      // Only process objects that look like batches (avoid prototype additions!)
      if (batch && batch.map) {
        if (batch.req) {
          batch.req.abort();
        }
      }
    }

    // If we have used reverse ajax then we try to tell the server we are gone
    if (dwr.engine._isNotifyServerOnPageUnload) {
      dwr.engine._debug("calling unloader for: " + dwr.engine._scriptSessionId);
      batch = {
        map:{
          callCount:1,
          'c0-scriptName':'__System',
          'c0-methodName':'pageUnloaded',
          'c0-id':0
        },
        paramCount:0, isPoll:false, async:true,
        headers:{}, preHooks:[], postHooks:[],
        timeout:dwr.engine._timeout,
        errorHandler:null, warningHandler:null, textHtmlHandler:null,
        path:dwr.engine._pathToDwrServlet,
        handlers:[{ exceptionHandler:null, callback:null }]
      };
      dwr.engine.transport.send(batch);
      dwr.engine._isNotifyServerOnPageUnload = false;
    }
  };

  // Now register the unload handler
  if (!dwr.engine.isJaxerServer) {
    if (window.addEventListener) window.addEventListener('unload', dwr.engine._unloader, false);
    else if (window.attachEvent) window.attachEvent('onunload', dwr.engine._unloader);
  }

  /**
   * Send a request. Called by the JavaScript interface stub
   * @private
   * @param path part of URL after the host and before the exec bit without leading or trailing /s
   * @param scriptName The class to execute
   * @param methodName The method on said class to execute
   * @param func The callback function to which any returned data should be passed
   *       if this is null, any returned data will be ignored
   * @param args The parameters to passed to the above method
   */
  dwr.engine._execute = function(path, scriptName, methodName, args) {
    var singleShot = false;
    if (dwr.engine._batch == null) {
      dwr.engine.beginBatch();
      singleShot = true;
    }

    var batch = dwr.engine._batch;
    // All the paths MUST be to the same servlet
    if (batch.path == null) {
      batch.path = path;
    }
    else {
      if (batch.path != path) {
        dwr.engine._handleError(batch, { name:"dwr.engine.multipleServlets", message:"Can't batch requests to multiple DWR Servlets." });
        return;
      }
    }

    dwr.engine.batch.addCall(batch, scriptName, methodName, args);

    // Now we have finished remembering the call, we increment the call count
    batch.map.callCount++;
    if (singleShot) {
      return dwr.engine.endBatch();
    }
  };

  /**
   * Poll the server to see if there is any data waiting
   * @private
   */
  dwr.engine._poll = function() {
    if (!dwr.engine._activeReverseAjax) {
      return;
    }
    var batch = dwr.engine.batch.createPoll();
    dwr.engine.transport.send(batch);
  };

  /**
   * Try to recover from polling errors
   * @param {Object} msg
   * @param {Object} ex
   */
  dwr.engine._pollErrorHandler = function(msg, ex) {
    if (dwr.engine._pollRetries > dwr.engine._maxPollRetries) {
      dwr.engine._activeReverseAjax = false;
      dwr.engine._debug("Reverse Ajax poll failed (retries=" + dwr.engine._pollRetries + "). Giving Up: " + ex.name + " : " + ex.message);
      dwr.engine._debug("Giving up.");
      return;
    }

    var index = dwr.engine._pollRetries;
    if (index >= dwr.engine._retryIntervals.length) {
      index = dwr.engine._retryIntervals.length - 1;
    }

    dwr.engine._debug("Reverse Ajax poll failed (retries=" + dwr.engine._pollRetries + "). Trying again in " + dwr.engine._retryIntervals[index] + "s: " + ex.name + " : " + ex.message);
    setTimeout(dwr.engine._poll, 1000 * dwr.engine._retryIntervals[index]);

    dwr.engine._pollRetries++;
  };

  /** @private This is a hack to make the context be this window */
  dwr.engine._eval = function(script) {
    if (script == null) {
      return null;
    }
    if (script == "") {
      dwr.engine._debug("Warning: blank script", true);
      return null;
    }
    // dwr.engine._debug("Exec: [" + script + "]", true);
    return eval(script);
  };

  /** @private call all the post hooks for a batch */
  dwr.engine._callPostHooks = function(batch) {
    if (batch.postHooks) {
      for (var i = 0; i < batch.postHooks.length; i++) {
        batch.postHooks[i]();
      }
      batch.postHooks = null;
    }
  };

  /**
   * Generic error handling routing to save having null checks everywhere
   * @private
   * @param {Object} batch
   * @param {Object} ex
   */
  dwr.engine._handleError = function(batch, ex) {
    if (typeof ex == "string") ex = { name:"unknown", message:ex };
    if (ex.message == null) ex.message = "";
    if (ex.name == null) ex.name = "unknown";
    if (batch && typeof batch.errorHandler == "function") batch.errorHandler(ex.message, ex);
    else if (dwr.engine._errorHandler) dwr.engine._errorHandler(ex.message, ex);
    if (batch) dwr.engine.batch.remove(batch);
  };

  /**
   * Generic error handling routing to save having null checks everywhere
   * @private
   * @param {Object} batch
   * @param {Object} ex
   */
  dwr.engine._handleWarning = function(batch, ex) {
    if (typeof ex == "string") ex = { name:"unknown", message:ex };
    if (ex.message == null) ex.message = "";
    if (ex.name == null) ex.name = "unknown";
    if (batch && typeof batch.warningHandler == "function") batch.warningHandler(ex.message, ex);
    else if (dwr.engine._warningHandler) dwr.engine._warningHandler(ex.message, ex);
    if (batch) dwr.engine.batch.remove(batch);
  };

  /**
   * Used internally when some message needs to get to the programmer
   * @private
   * @param {String} message
   * @param {Object} stacktrace
   */
  dwr.engine._debug = function(message, stacktrace) {
    var written = false;
    try {
      if (window.console) {
        if (stacktrace && window.console.trace) window.console.trace();
        window.console.log(message);
        written = true;
      }
      else if (window.opera && window.opera.postError) {
        window.opera.postError(message);
        written = true;
      }
      else if (window.Jaxer && Jaxer.isOnServer) {
        Jaxer.Log.info(message);
        written = true;
      }
    }
    catch (ex) { /* ignore */ }

    if (!written) {
      var debug = document.getElementById("dwr-debug");
      if (debug) {
        var contents = message + "<br/>" + debug.innerHTML;
        if (contents.length > 2048) contents = contents.substring(0, 2048);
        debug.innerHTML = contents;
      }
    }
  };

  /**
   * Functions called by the server
   */
  dwr.engine.remote = {
    /**
     * Execute a callback
     * @private
     * @param {int} batchId The ID of the batch that we are replying to
     * @param {int} callId The call ID that the script relates to
     * @param {String} reply The script to execute
     */
    handleCallback:function(batchId, callId, reply) {
      var batch = dwr.engine._batches[batchId];
      if (batch == null) {
        dwr.engine._debug("Warning: batch == null in remoteHandleCallback for batchId=" + batchId, true);
        return;
      }

      // We store the reply in the batch so that in sync mode we can return the data
      batch.reply = reply;

      // Error handlers inside here indicate an error that is nothing to do
      // with DWR so we handle them differently.
      try {
        var handlers = batch.handlers[callId];
        if (!handlers) {
          dwr.engine._debug("Warning: Missing handlers. callId=" + callId, true);
        }
        else {
          batch.handlers[callId].completed = true;
          if (typeof handlers.callback == "function") {
            handlers.callback.apply(handlers.callbackScope, [ reply, handlers.callbackArg ]);
          }
        }
      }
      catch (ex) {
        dwr.engine._handleError(batch, ex);
      }
    },

    /**
     * Called by the server when a JavascriptFunction is executed
     * @param id The ID of the serialized function
     * @param args The arguments to pass to the function
     */
    handleFunctionCall:function(id, args) {
      var func = dwr.engine.serialize.remoteFunctions[id];
      func.apply(window, args);
    },

    /**
     * Called by the server when a JavascriptFunction is executed
     * @param id The ID of the serialized function
     * @param args The arguments to pass to the function
     */
    handleObjectCall:function(id, methodName, args) {
      var obj = dwr.engine.serialize.remoteFunctions[id];
      obj[methodName].apply(obj, args);
    },

    /**
     * Called by the server when a JavascriptFunction is executed
     * @param propertyName The ID of the serialized function
     * @param data The arguments to pass to the function
     */
    handleSetCall:function(id, propertyName, data) {
      var obj = dwr.engine.serialize.remoteFunctions[id];
      obj[propertyName] = data;
    },

    /**
     * Called by the server when a JavascriptFunction is closed
     * @param id The ID of the serialized function
     */
    handleFunctionClose:function(id) {
      delete dwr.engine.serialize.remoteFunctions[id];
    },

    /**
     * Called by the server: Handle an exception for a call
     * @private
     * @param {int} batchId The ID of the batch that we are replying to
     * @param {int} callId The call ID that the script relates to
     * @param {String} reply The script to execute
     */
    handleException:function(batchId, callId, ex) {
      var batch = dwr.engine._batches[batchId];
      if (batch == null) {
        dwr.engine._debug("Warning: null batch in remoteHandleException", true);
        return;
      }

      var handlers = batch.handlers[callId];
      batch.handlers[callId].completed = true;
      if (handlers == null) {
        dwr.engine._debug("Warning: null handlers in remoteHandleException", true);
        return;
      }

      if (ex.message == undefined) {
        ex.message = ""; 
      }

      if (typeof handlers.exceptionHandler == "function") {
        handlers.exceptionHandler.call(handlers.exceptionScope, ex.message, ex, handlers.exceptionArg);
      }
      else if (typeof batch.errorHandler == "function") {
        batch.errorHandler(ex.message, ex);
      }
    },

    /**
     * Called by the server: The whole batch is broken
     * @private
     * @param {Object} ex The data about what broke
     * @param {int} batchId The ID of the batch that we are replying to
     */
    handleBatchException:function(ex, batchId) {
      var searchBatch = (dwr.engine._receivedBatch == null && batchId != null);
      if (searchBatch) {
        dwr.engine._receivedBatch = dwr.engine._batches[batchId];
      }