@NotNull
@Override
public Promise<WebRTCSessionDescription> setRemoteDescription(@NotNull final WebRTCSessionDescription description) {
    return new Promise<>(new PromiseFunc<WebRTCSessionDescription>() {
        @Override
        public void exec(@NotNull final PromiseResolver<WebRTCSessionDescription> resolver) {
            peerConnection.setRemoteDescription(JsSessionDescription.create(description.getType(),
                    description.getSdp()), new JsClosure() {
                @Override
                public void callback() {
                    resolver.result(description);
                }
            }, new JsClosureError() {
                @Override
                public void onError(JavaScriptObject error) {
                    resolver.error(new JavaScriptException(error));
                }
            });
        }
    });
}
 

private static void doReportStacktrace(Exception exception) {
    // Defer without $entry to bypass some of GWT's exception handling
    deferWithoutEntry(() -> {
        // Bypass regular exception reporting
        UncaughtExceptionHandler originalHandler = GWT
                .getUncaughtExceptionHandler();
        GWT.setUncaughtExceptionHandler(
                ignore -> GWT.setUncaughtExceptionHandler(originalHandler));

        // Throw in the appropriate way
        if (exception instanceof JavaScriptException) {
            // Throw originally thrown instance through JS
            jsThrow(((JavaScriptException) exception).getThrown());
        } else {
            throw exception;
        }
    });
}
 

private void onBeforeUnload(Event event) {
    captureCurrentScrollPositions();

    JsonObject stateObject = createStateObjectWithHistoryIndexAndToken();

    JsonObject sessionStorageObject = Json.createObject();
    sessionStorageObject.put(X_POSITIONS,
            convertArrayToJsonArray(xPositions));
    sessionStorageObject.put(Y_POSITIONS,
            convertArrayToJsonArray(yPositions));

    Browser.getWindow().getHistory().replaceState(stateObject, "",
            Browser.getWindow().getLocation().getHref());
    try {
        Browser.getWindow().getSessionStorage().setItem(
                createSessionStorageKey(historyResetToken),
                sessionStorageObject.toJson());
    } catch (JavaScriptException e) {
        Console.error("Failed to get session storage: " + e.getMessage());
    }
}
 

private static XMLHttpRequest request(XMLHttpRequest xhr, String method,
        String url, String requestData, String contentType,
        Callback callback) {
    try {
        xhr.setOnReadyStateChange(new Handler(callback));
        xhr.open(method, url);
        xhr.setRequestHeader("Content-type", contentType);
        xhr.setWithCredentials(true);
        xhr.send(requestData);
    } catch (JavaScriptException e) {
        // Just fail.
        Console.error(e);
        callback.onFail(xhr, e);
        xhr.clearOnReadyStateChange();
    }
    return xhr;
}
 

public void load() {
    String item = localStorage.getItem(documentsKey());
    if (item != null) {
        idCounter = Long.parseLong(item);
    }
    try {
        loadInternal(indexKey());
        if (indexRef == null) {
            // no index found in local storage
            reset();
        } else {
            Log.info("Loaded " + idCounter + " documents from index at " + indexKey());
        }
    } catch (JavaScriptException e) {
        // load must be fail safe, so ignore any errors and reset
        reset();
    }
}
 

/**
 * Load the blocks described by blocksContent into the blocks workspace.
 *
 * @param formJson JSON description of Form's structure for upgrading
 * @param blocksContent XML description of a blocks workspace in format expected by Blockly
 * @throws LoadBlocksException if Blockly throws an uncaught exception
 */
// [lyn, 2014/10/27] added formJson for upgrading
public void loadBlocksContent(String formJson, String blocksContent) throws LoadBlocksException {
  try {
    doLoadBlocksContent(formJson, blocksContent);
  } catch (JavaScriptException e) {
    loadError = true;
    ErrorReporter.reportError(MESSAGES.blocksLoadFailure(formName));
    OdeLog.elog("Error loading blocks for screen " + formName + ": "
        + e.getDescription());
    throw new LoadBlocksException(e, formName);
  } finally {
    loadComplete = true;
  }
}
 

/**
 * Get Yail code for current blocks workspace
 *
 * @return the yail code as a String
 * @throws YailGenerationException if there was a problem generating the Yail
 */
public String getYail(String formJson, String packageName) throws YailGenerationException {
  try {
    return doGetYail(formJson, packageName);
  } catch (JavaScriptException e) {
    throw new YailGenerationException(e.getDescription(), formName);
  }
}
 

public void sendComponentData(String formJson, String packageName, boolean force) throws YailGenerationException {
  if (!currentForm.equals(formName)) { // Not working on the current form...
    OdeLog.log("Not working on " + currentForm + " (while sending for " + formName + ")");
    return;
  }
  try {
    doSendJson(formJson, packageName, force);
  } catch (JavaScriptException e) {
    throw new YailGenerationException(e.getDescription(), formName);
  }
}
 

@NotNull
@Override
public Promise<WebRTCSessionDescription> setLocalDescription(@NotNull final WebRTCSessionDescription description) {
    return new Promise<>(new PromiseFunc<WebRTCSessionDescription>() {
        @Override
        public void exec(@NotNull final PromiseResolver<WebRTCSessionDescription> resolver) {
            peerConnection.setLocalDescription(JsSessionDescription.create(description.getType(), description.getSdp()), () -> {
                resolver.result(description);
            }, error -> resolver.error(new JavaScriptException(error)));
        }
    }

    );
}
 

private void readAndRestoreScrollPositionsFromHistoryAndSessionStorage(
        boolean delayAfterResponse) {
    // restore history index & token from state if applicable
    JsonObject state = (JsonObject) Browser.getWindow().getHistory()
            .getState();
    if (state != null && state.hasKey(HISTORY_INDEX)
            && state.hasKey(HISTORY_TOKEN)) {

        currentHistoryIndex = (int) state.getNumber(HISTORY_INDEX);
        historyResetToken = state.getNumber(HISTORY_TOKEN);

        String jsonString = null;
        try {
            jsonString = Browser.getWindow().getSessionStorage()
                    .getItem(createSessionStorageKey(historyResetToken));
        } catch (JavaScriptException e) {
            Console.error(
                    "Failed to get session storage: " + e.getMessage());
        }
        if (jsonString != null) {
            JsonObject jsonObject = Json.parse(jsonString);

            xPositions = convertJsonArrayToArray(
                    jsonObject.getArray(X_POSITIONS));
            yPositions = convertJsonArrayToArray(
                    jsonObject.getArray(Y_POSITIONS));
            // array lengths checked in restoreScrollPosition
            restoreScrollPosition(delayAfterResponse);
        } else {
            Console.warn(
                    "History.state has scroll history index, but no scroll positions found from session storage matching token <"
                            + historyResetToken
                            + ">. User has navigated out of site in an unrecognized way.");
            resetScrollPositionTracking();
        }
    } else {
        resetScrollPositionTracking();
    }
}
 

private static XMLHttpRequest request(XMLHttpRequest xhr, String method,
        String url, final Callback callback) {
    try {
        xhr.setOnReadyStateChange(new Handler(callback));
        xhr.open(method, url);
        xhr.send();
    } catch (JavaScriptException e) {
        // Just fail.
        Console.error(e);
        callback.onFail(xhr, e);
        xhr.clearOnReadyStateChange();
    }
    return xhr;
}
 

/**
 * Create a JsonMessage object from the given json
 * @param json The JSON String to load from.
 * @return true if evaluation is successful, false otherwise.
 */
public static JsonMessage createJsonMessage(String json) throws JsonException {
  try {
    JsonMessage obj = (JsonMessage) serializer.parse(json);
    registerNativeJsonMessageToString(obj);
    return obj;
  } catch (JavaScriptException e) {
    throw new JsonException(e);
  }
}
 

/**
 * Create a JsonMessage object from the given json
 * @param json The JSON String to load from.
 * @return true if evaluation is successful, false otherwise.
 */
public static JsonMessage createJsonMessage(RawStringData data) throws JsonException {
  try {
    JsonMessage obj = (JsonMessage) serializer.parse(data.getBaseString());
    JsonHelper.registerRawStringData(obj, data);
    registerNativeJsonMessageToString(obj);
    return obj;
  } catch (JavaScriptException e) {
    throw new JsonException(e);
  }
}
 

public final void setAnchorAndFocus(Node anchorNode, int anchorOffset,
    Node focusNode, int focusOffset) {
  if (QuirksConstants.HAS_BASE_AND_EXTENT) {
    // NOTE(danilatos): While extend() would also work for webkit,
    // we have to use setBaseAndExtent because it appears to reuse
    // the existing range, rather than needing to replace it, and
    // doing otherwise stuffs up the IME composition state
    setBaseAndExtent(anchorNode, anchorOffset, focusNode, focusOffset);
  } else {

    // We assume that anchor node is in the same focusable area.
    // If not, death will ensue.
    setFocusElement(focusNode);

    // TODO(danilatos): Investigate just using extend() twice - i.e.
    // extend to the anchor -> collapse to end -> extend to the focus.
    JsRange range = JsRange.create();
    range.setStart(anchorNode, anchorOffset);
    range.collapse(true);

    removeAllRanges();
    addRange(range);

    if (focusNode != anchorNode || focusOffset != anchorOffset) {
      try {
          extend(focusNode, focusOffset);
      } catch (JavaScriptException e) {
        NativeSelectionUtil.LOG.error().logPlainText(
            "error extending selection from " + anchorNode + ":" + anchorOffset +
            " to " + focusNode + ":" + focusOffset);
        removeAllRanges();
        range = JsRange.create();
        range.setStart(anchorNode, anchorOffset);
        range.collapse(true);
        range.setEnd(focusNode, focusOffset);
        addRange(range);
      }
    }
  }
}
 

@Override
PointRange<Node> getOrdered() {
  // NOTE(user): try/catch here as JsTextRangeIE.duplicate throws an exception if the
  // selection is non-text, i.e. an image. Its much safer to wrap these IE native methods.
  // TODO(user): Decide whether returning null is the correct behaviour when exception is
  // thrown. If so, remove the logger.error().
  try {
    // Get selection + corresponding text range
    JsSelectionIE selection = JsSelectionIE.get();
    JsTextRangeIE start = selection.createRange();

    // Best test we have found for empty selection
    if (checkNoSelection(selection, start)) {
      return null;
    }

    // create two collapsed ranges, for each end of the selection
    JsTextRangeIE end = start.duplicate();
    start.collapse(true);
    end.collapse(false);

    // Translate to HtmlPoints
    Point<Node> startPoint = pointAtCollapsedRange(start);

    return JsTextRangeIE.equivalent(start, end) ? new PointRange<Node>(startPoint)
        : new PointRange<Node>(startPoint, pointAtCollapsedRange(end));
  } catch (JavaScriptException e) {
    logger.error().log("Cannot get selection", e);
    return null;
  }
}
 

private void setHeaders(Headers headers, XMLHttpRequest xmlHttpRequest) throws JavaScriptException {
    if (headers != null && headers.size() > 0) {
        for (Header header : headers) {
            xmlHttpRequest.setRequestHeader(header.getName(), header.getValue());
        }
    }
}
 

@Override
public void auth(PreparedRequest preparedRequest) {
    try {
        preparedRequest.setHeader("Authorization", "Basic " + btoa(user + ":" + password));
    } catch (JavaScriptException e) {
        throw new UnsupportedOperationException("It was not possible to encode credentials using browser's " +
                "native btoa. The browser does not support this operation.", e);
    }
    preparedRequest.setWithCredentials(withCredentials);
    preparedRequest.send();
}
 

/**
 * Create a JsonMessage object from the given json
 * @param json The JSON String to load from.
 * @return true if evaluation is successful, false otherwise.
 */
public static JsonMessage createJsonMessage(String json) throws JsonException {
  try {
    JsonMessage obj = (JsonMessage) serializer.parse(json);
    registerNativeJsonMessageToString(obj);
    return obj;
  } catch (JavaScriptException e) {
    throw new JsonException(e);
  }
}
 

/**
 * Create a JsonMessage object from the given json
 * @param json The JSON String to load from.
 * @return true if evaluation is successful, false otherwise.
 */
public static JsonMessage createJsonMessage(RawStringData data) throws JsonException {
  try {
    JsonMessage obj = (JsonMessage) serializer.parse(data.getBaseString());
    JsonHelper.registerRawStringData(obj, data);
    registerNativeJsonMessageToString(obj);
    return obj;
  } catch (JavaScriptException e) {
    throw new JsonException(e);
  }
}
 

public final void setAnchorAndFocus(Node anchorNode, int anchorOffset,
    Node focusNode, int focusOffset) {
  if (QuirksConstants.HAS_BASE_AND_EXTENT) {
    // NOTE(danilatos): While extend() would also work for webkit,
    // we have to use setBaseAndExtent because it appears to reuse
    // the existing range, rather than needing to replace it, and
    // doing otherwise stuffs up the IME composition state
    setBaseAndExtent(anchorNode, anchorOffset, focusNode, focusOffset);
  } else {

    // We assume that anchor node is in the same focusable area.
    // If not, death will ensue.
    setFocusElement(focusNode);

    // TODO(danilatos): Investigate just using extend() twice - i.e.
    // extend to the anchor -> collapse to end -> extend to the focus.
    JsRange range = JsRange.create();
    range.setStart(anchorNode, anchorOffset);
    range.collapse(true);

    removeAllRanges();
    addRange(range);

    if (focusNode != anchorNode || focusOffset != anchorOffset) {
      try {
          extend(focusNode, focusOffset);
      } catch (JavaScriptException e) {
        NativeSelectionUtil.LOG.error().logPlainText(
            "error extending selection from " + anchorNode + ":" + anchorOffset +
            " to " + focusNode + ":" + focusOffset);
        removeAllRanges();
        range = JsRange.create();
        range.setStart(anchorNode, anchorOffset);
        range.collapse(true);
        range.setEnd(focusNode, focusOffset);
        addRange(range);
      }
    }
  }
}
 

@Override
PointRange<Node> getOrdered() {
  // NOTE(user): try/catch here as JsTextRangeIE.duplicate throws an exception if the
  // selection is non-text, i.e. an image. Its much safer to wrap these IE native methods.
  // TODO(user): Decide whether returning null is the correct behaviour when exception is
  // thrown. If so, remove the logger.error().
  try {
    // Get selection + corresponding text range
    JsSelectionIE selection = JsSelectionIE.get();
    JsTextRangeIE start = selection.createRange();

    // Best test we have found for empty selection
    if (checkNoSelection(selection, start)) {
      return null;
    }

    // create two collapsed ranges, for each end of the selection
    JsTextRangeIE end = start.duplicate();
    start.collapse(true);
    end.collapse(false);

    // Translate to HtmlPoints
    Point<Node> startPoint = pointAtCollapsedRange(start);

    return JsTextRangeIE.equivalent(start, end) ? new PointRange<Node>(startPoint)
        : new PointRange<Node>(startPoint, pointAtCollapsedRange(end));
  } catch (JavaScriptException e) {
    logger.error().log("Cannot get selection", e);
    return null;
  }
}
 

private void doExecute(Runnable r) {
  try {
    r.run();
  } catch (JavaScriptException jse) {
    if (jse.isThrownSet()) {
      LOG.severe("Caught JavaScriptException, wrapped error is: " + jse.getThrown());
    }
    ThrowableHandlers.handle(jse);
  } catch (Throwable t) {
    ThrowableHandlers.handle(t);
  }
}
 

public LoadBlocksException(JavaScriptException e, String formName) {
  super(e);
  this.formName = formName;
}
 

/**
 * IE-specific trick to keep an empty paragraph "open" (i.e. prevent it from
 * collapsing to zero height). See class javadoc for details.
 *
 * Since we know of no direct way to set the magic flag, we mimic the user
 * deleting the last char.
 *
 * TODO(user): can we get away with only doing this when creating new, empty
 * paragraphs? It seems our own emptying should already set the magic flag,
 * but for some reason it doesn't seem to happen...
 *
 * NB(user): The flag only gets set when the nodelet is attached to the
 * editor. See also ImplementorImpl.Helper#beforeImplementation(Element)
 */
public static void openEmptyParagraph(Element nodelet) {
  // Add + delete an arbitrary char from the paragraph
  // TODO(user): why does this throw exception in <caption> elements?
  try {
    Point<Node> point = IeNodeletHelper.beforeImplementation(nodelet);
    nodelet.setInnerHTML("x");
    nodelet.setInnerHTML("");
    IeNodeletHelper.afterImplementation(nodelet, point);
  } catch (JavaScriptException t) {}
}
 

/**
 * IE-specific trick to keep an empty paragraph "open" (i.e. prevent it from
 * collapsing to zero height). See class javadoc for details.
 *
 * Since we know of no direct way to set the magic flag, we mimic the user
 * deleting the last char.
 *
 * TODO(user): can we get away with only doing this when creating new, empty
 * paragraphs? It seems our own emptying should already set the magic flag,
 * but for some reason it doesn't seem to happen...
 *
 * NB(user): The flag only gets set when the nodelet is attached to the
 * editor. See also ImplementorImpl.Helper#beforeImplementation(Element)
 */
public static void openEmptyParagraph(Element nodelet) {
  // Add + delete an arbitrary char from the paragraph
  // TODO(user): why does this throw exception in <caption> elements?
  try {
    Point<Node> point = IeNodeletHelper.beforeImplementation(nodelet);
    nodelet.setInnerHTML("x");
    nodelet.setInnerHTML("");
    IeNodeletHelper.afterImplementation(nodelet, point);
  } catch (JavaScriptException t) {}
}
 

/**
 * Get a Date object mapped to the specified key.
 *
 * @param key The name of the Date property.
 * @return A Date object, or null if the key is not found.
 * @throws com.google.gwt.core.client.JavaScriptException if the key is found but the object returned
 * is not a Date.
 * @throws TypeException If the key is found but the value is not an object.
 */
public final Date getDate(String key)
    throws JavaScriptException, TypeException {
  return JsDate.toJava((JsDate) getObject(key));
}