public Legal checkEdgeLegality(final Direction direction, final String label) {
        if (null == this.edgeFilter)
            return Legal.YES;
        if (this.checkEdgeLegality(direction).negative())
            return Legal.NO;
        final Map<String, Legal> legalMap = this.edgeLegality.get(direction);
        if (legalMap.containsKey(label))
            return legalMap.get(label);
        else if (legalMap.containsKey(null))
            return legalMap.get(null);
        else
            return Legal.NO;
    }
Get the legality of a particular edge direction and label.

@param direction the direction of the edge.
@param label     the label of the edge.
@return the {@link Legal} of the arguments.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/computer/GraphFilter.java