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/*
* 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.commons.math3.geometry.partitioning;
import org.apache.commons.math3.geometry.Space;
/** This interface represents the remaining parts of an hyperplane after
* other parts have been chopped off.
* sub-hyperplanes are obtained when parts of an {@link
* Hyperplane hyperplane} are chopped off by other hyperplanes that
* intersect it. The remaining part is a convex region. Such objects
* appear in {@link BSPTree BSP trees} as the intersection of a cut
* hyperplane with the convex region which it splits, the chopping
* hyperplanes are the cut hyperplanes closer to the tree root.
*
* Note that this interface is not intended to be implemented
* by Apache Commons Math users, it is only intended to be implemented
* within the library itself. New methods may be added even for minor
* versions, which breaks compatibility for external implementations.
*
* @param Type of the embedding space.
* @since 3.0
*/
public interface SubHyperplane {
/** Copy the instance.
* The instance created is completely independent of the original
* one. A deep copy is used, none of the underlying objects are
* shared (except for the nodes attributes and immutable
* objects).
* @return a new sub-hyperplane, copy of the instance
*/
SubHyperplane copySelf();
/** Get the underlying hyperplane.
* @return underlying hyperplane
*/
Hyperplane getHyperplane();
/** Check if the instance is empty.
* @return true if the instance is empty
*/
boolean isEmpty();
/** Get the size of the instance.
* @return the size of the instance (this is a length in 1D, an area
* in 2D, a volume in 3D ...)
*/
double getSize();
/** Compute the relative position of the instance with respect
* to an hyperplane.
* @param hyperplane hyperplane to check instance against
* @return one of {@link Side#PLUS}, {@link Side#MINUS}, {@link Side#BOTH},
* {@link Side#HYPER}
* @deprecated as of 3.6, replaced with {@link #split(Hyperplane)}.{@link SplitSubHyperplane#getSide()}
*/
@Deprecated
Side side(Hyperplane hyperplane);
/** Split the instance in two parts by an hyperplane.
* @param hyperplane splitting hyperplane
* @return an object containing both the part of the instance
* on the plus side of the hyperplane and the part of the
* instance on the minus side of the hyperplane
*/
SplitSubHyperplane split(Hyperplane hyperplane);
/** Compute the union of the instance and another sub-hyperplane.
* @param other other sub-hyperplane to union (must be in the
* same hyperplane as the instance)
* @return a new sub-hyperplane, union of the instance and other
*/
SubHyperplane reunite(SubHyperplane other);
/** Class holding the results of the {@link #split split} method.
* @param Type of the embedding space.
*/
class SplitSubHyperplane {
/** Part of the sub-hyperplane on the plus side of the splitting hyperplane. */
private final SubHyperplane plus;
/** Part of the sub-hyperplane on the minus side of the splitting hyperplane. */
private final SubHyperplane minus;
/** Build a SplitSubHyperplane from its parts.
* @param plus part of the sub-hyperplane on the plus side of the
* splitting hyperplane
* @param minus part of the sub-hyperplane on the minus side of the
* splitting hyperplane
*/
public SplitSubHyperplane(final SubHyperplane plus,
final SubHyperplane minus) {
this.plus = plus;
this.minus = minus;
}
/** Get the part of the sub-hyperplane on the plus side of the splitting hyperplane.
* @return part of the sub-hyperplane on the plus side of the splitting hyperplane
*/
public SubHyperplane getPlus() {
return plus;
}
/** Get the part of the sub-hyperplane on the minus side of the splitting hyperplane.
* @return part of the sub-hyperplane on the minus side of the splitting hyperplane
*/
public SubHyperplane getMinus() {
return minus;
}
/** Get the side of the split sub-hyperplane with respect to its splitter.
* @return {@link Side#PLUS} if only {@link #getPlus()} is neither null nor empty,
* {@link Side#MINUS} if only {@link #getMinus()} is neither null nor empty,
* {@link Side#BOTH} if both {@link #getPlus()} and {@link #getMinus()}
* are neither null nor empty or {@link Side#HYPER} if both {@link #getPlus()} and
* {@link #getMinus()} are either null or empty
* @since 3.6
*/
public Side getSide() {
if (plus != null && !plus.isEmpty()) {
if (minus != null && !minus.isEmpty()) {
return Side.BOTH;
} else {
return Side.PLUS;
}
} else if (minus != null && !minus.isEmpty()) {
return Side.MINUS;
} else {
return Side.HYPER;
}
}
}
}