| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.apache.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: |
| * <p/> |
| * <pre> |
| * gremlin--knows-->rexster |
| * </pre> |
| * 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) |
| * @author Stephen Mallette (http://stephen.genoprime.com) |
| */ |
| public enum Direction { |
| |
| /** |
| * Refers to an outgoing direction. |
| */ |
| OUT, |
| |
| /** |
| * Refers to an incoming direction. |
| */ |
| IN, |
| |
| /** |
| * Refers to either direction ({@link #IN} or {@link #OUT}). |
| */ |
| BOTH; |
| |
| /** |
| * The actual direction of an {@link Edge} may only be {@link #IN} or {@link #OUT}, as defined in this array. |
| */ |
| public static final Direction[] proper = new Direction[]{OUT, IN}; |
| |
| /** |
| * Produce the opposite representation of the current {@code Direction} enum. |
| */ |
| public Direction opposite() { |
| if (this.equals(OUT)) |
| return IN; |
| else if (this.equals(IN)) |
| return OUT; |
| else |
| return BOTH; |
| } |
| } |