Set<RelationFrame> rframes = inverse_parent_cache.get(child);
Set<RelationFrame> rframes = inverse_parent_cache.get(parent);
    private void decacheRelation(RelationFrame relationship) {	synchronized (relation_lock) {	    DataFrame child = child_cache.get(relationship);	    if (child != null) {		Set<RelationFrame> rframes = inverse_child_cache.get(child);		if (rframes != null) {		    rframes.remove(relationship);		}	    }	    DataFrame parent = parent_cache.get(relationship);	    if (parent != null) {		Set<RelationFrame> rframes = inverse_parent_cache.get(child);		if (rframes != null) {		    rframes.remove(relationship);		}	    }	    child_cache.remove(relationship);	    parent_cache.remove(relationship);		    pending_relations.remove(relationship);	}	if (isContainmentRelation(relationship)) {	    synchronized (containers) {		Frame child = getRelationshipChild(relationship);		if (child != null) containers.remove(child);	    }	}    }