public void initEditor(WebView editor, File sourceFile, boolean isBlank) {
    this.editor = editor;
    targetFile = sourceFile;
    if (targetFile != null) {
        filename = targetFile.getName();
    }

    editor.getEngine().getLoadWorker().stateProperty().addListener(
            (value, old, newState) -> {
                if (newState == Worker.State.SUCCEEDED) {
                    JSObject document = (JSObject) editor.getEngine().executeScript("window");
                    document.setMember("java", this);
                    Platform.runLater(()->createEditor(isBlank));
                }
            });

    editor.getEngine().setPromptHandler((PromptData prompt) -> {
        TextInputDialog dialog = new TextInputDialog(prompt.getDefaultValue());
        dialog.setTitle("Jace IDE");
        dialog.setHeaderText("Respond and press OK, or Cancel to abort");
        dialog.setContentText(prompt.getMessage());
        return dialog.showAndWait().orElse(null);
    });

    editor.getEngine().load(getClass().getResource(CODEMIRROR_EDITOR).toExternalForm());
}