public boolean setNameFilter(final String nameFilter, final boolean forceChange) {
            final String filter = NullSafe.get(
                    nameFilter,
                    String::trim,
                    str -> str.length() == 0
                            ? null
                            : str);

            if (!forceChange && ((NullSafe.allNull(filter, this.nameFilter))
                    || (filter != null && filter.equals(this.nameFilter)))) {
                return false;
            } else {
                this.nameFilter = filter;
                this.nameFilterChange = true;

                return true;
            }
        }
This sets the name filter to be used when fetching items. This method
returns false is the filter is set to the same value that is already set.
stroom-core-shared/src/main/java/stroom/explorer/shared/ExplorerTreeFilter.java