public PropertyPath merge(final String... parts) {
        if (parts == null || parts.length == 0) {
            return this;
        } else {
            return new PropertyPath(this.getParts(), Arrays.asList(parts));
        }
    }
Merge parts onto the end of this and return a new {@link PropertyPath}
stroom-util-shared/src/main/java/stroom/util/shared/PropertyPath.java