1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * https://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 /*
19 * This is not the original file distributed by the Apache Software Foundation
20 * It has been modified by the Hipparchus project
21 */
22 package org.hipparchus.geometry.partitioning;
23
24 import org.hipparchus.geometry.Space;
25
26 /** This interface is used to visit {@link BSPTree BSP tree} nodes.
27
28 * <p>Navigation through {@link BSPTree BSP trees} can be done using
29 * two different point of views:</p>
30 * <ul>
31 * <li>
32 * the first one is in a node-oriented way using the {@link
33 * BSPTree#getPlus}, {@link BSPTree#getMinus} and {@link
34 * BSPTree#getParent} methods. Terminal nodes without associated
35 * {@link SubHyperplane sub-hyperplanes} can be visited this way,
36 * there is no constraint in the visit order, and it is possible
37 * to visit either all nodes or only a subset of the nodes
38 * </li>
39 * <li>
40 * the second one is in a sub-hyperplane-oriented way using
41 * classes implementing this interface which obeys the visitor
42 * design pattern. The visit order is provided by the visitor as
43 * each node is first encountered. Each node is visited exactly
44 * once.
45 * </li>
46 * </ul>
47
48 * @param <S> Type of the space.
49
50 * @see BSPTree
51 * @see SubHyperplane
52
53 */
54 public interface BSPTreeVisitor<S extends Space> {
55
56 /** Enumerate for visit order with respect to plus sub-tree, minus sub-tree and cut sub-hyperplane. */
57 enum Order {
58 /** Indicator for visit order plus sub-tree, then minus sub-tree,
59 * and last cut sub-hyperplane.
60 */
61 PLUS_MINUS_SUB,
62
63 /** Indicator for visit order plus sub-tree, then cut sub-hyperplane,
64 * and last minus sub-tree.
65 */
66 PLUS_SUB_MINUS,
67
68 /** Indicator for visit order minus sub-tree, then plus sub-tree,
69 * and last cut sub-hyperplane.
70 */
71 MINUS_PLUS_SUB,
72
73 /** Indicator for visit order minus sub-tree, then cut sub-hyperplane,
74 * and last plus sub-tree.
75 */
76 MINUS_SUB_PLUS,
77
78 /** Indicator for visit order cut sub-hyperplane, then plus sub-tree,
79 * and last minus sub-tree.
80 */
81 SUB_PLUS_MINUS,
82
83 /** Indicator for visit order cut sub-hyperplane, then minus sub-tree,
84 * and last plus sub-tree.
85 */
86 SUB_MINUS_PLUS;
87 }
88
89 /** Determine the visit order for this node.
90 * <p>Before attempting to visit an internal node, this method is
91 * called to determine the desired ordering of the visit. It is
92 * guaranteed that this method will be called before {@link
93 * #visitInternalNode visitInternalNode} for a given node, it will be
94 * called exactly once for each internal node.</p>
95 * @param node BSP node guaranteed to have a non null cut sub-hyperplane
96 * @return desired visit order, must be one of
97 * {@link Order#PLUS_MINUS_SUB}, {@link Order#PLUS_SUB_MINUS},
98 * {@link Order#MINUS_PLUS_SUB}, {@link Order#MINUS_SUB_PLUS},
99 * {@link Order#SUB_PLUS_MINUS}, {@link Order#SUB_MINUS_PLUS}
100 */
101 Order visitOrder(BSPTree<S> node);
102
103 /** Visit a BSP tree node node having a non-null sub-hyperplane.
104 * <p>It is guaranteed that this method will be called after {@link
105 * #visitOrder visitOrder} has been called for a given node,
106 * it wil be called exactly once for each internal node.</p>
107 * @param node BSP node guaranteed to have a non null cut sub-hyperplane
108 * @see #visitLeafNode
109 */
110 void visitInternalNode(BSPTree<S> node);
111
112 /** Visit a leaf BSP tree node node having a null sub-hyperplane.
113 * @param node leaf BSP node having a null sub-hyperplane
114 * @see #visitInternalNode
115 */
116 void visitLeafNode(BSPTree<S> node);
117
118 }