public Builder parent(final Meta parent) {
            // Set effective time from the parent data.
            if (parent != null) {
                parentId = parent.getId();
                if (effectiveMs == null) {
                    if (parent.getEffectiveMs() != null) {
                        effectiveMs = parent.getEffectiveMs();
                    } else {
                        effectiveMs = parent.getCreateMs();
                    }
                }
            } else {
                parentId = null;
            }

            return this;
        }
This is a utility method to perform common parent association behaviour, e.g.
setting the effective time from the parent.

@param parent The parent to set.
@return The builder.
stroom-meta/stroom-meta-api/src/main/java/stroom/meta/api/MetaProperties.java