com.tinkerpop.gremlin.structure.Direction Maven / Gradle / Ivy

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package com.tinkerpop.gremlin.structure;

/**
 * {@link Direction} is used to denote the direction of an {@link Edge} or location of a {@link Vertex} on an
 * {@link Edge}. For example:
 * 
 * 
 * gremlin--knows-->rexster
 * 
 * is an {@link Direction#OUT} {@link Edge} for Gremlin and an {@link Direction#IN} edge for Rexster. Moreover, given
 * that {@link Edge}, Gremlin is the {@link Direction#OUT} {@link Vertex} and Rexster is the {@link Direction#IN}
 * {@link Vertex}.
 *
 * @author Marko A. Rodriguez (http://markorodriguez.com)
 */
public enum Direction {

    OUT, IN, BOTH;

    public static final Direction[] proper = new Direction[]{OUT, IN};

    /**
     * Produce the opposite representation of the current {@code Contains} object.
     */
    public Direction opposite() {
        if (this.equals(OUT))
            return IN;
        else if (this.equals(IN))
            return OUT;
        else
            return BOTH;
    }
}