public void addAll(final Indicator indicator) {
        if (indicator != null) {
            for (final Entry<Severity, Set<StoredError>> entry : indicator.errorMap.entrySet()) {
                if (entry.getValue() != null && entry.getValue().size() > 0) {
                    Set<StoredError> messages = errorMap.get(entry.getKey());
                    if (messages == null) {
                        messages = new HashSet<>(entry.getValue().size());
                    }

                    if (entry.getValue() != null) {
                        messages.addAll(entry.getValue());
                    }
                }
            }
        }
    }
Stores details of warnings, errors and fatal errors.
stroom-core-client-widget/src/main/java/stroom/editor/client/view/Indicator.java