SphericalPolygonsSetTransferObject.java
/* Copyright 2002-2019 CS Systèmes d'Information
* Licensed to CS Systèmes d'Information (CS) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* CS 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.orekit.utils;
import java.io.Serializable;
import org.hipparchus.geometry.euclidean.threed.Vector3D;
import org.hipparchus.geometry.partitioning.BSPTree;
import org.hipparchus.geometry.partitioning.BSPTreeVisitor;
import org.hipparchus.geometry.spherical.twod.Circle;
import org.hipparchus.geometry.spherical.twod.Sphere2D;
import org.hipparchus.geometry.spherical.twod.SphericalPolygonsSet;
/** Transfer object for serializing {@link SphericalPolygonsSet} instances.
* <p>
* This object is intended to be used when {@link SphericalPolygonsSet} instances
* needs to be serialized. Instead of serializing the zone, an instance of
* this class is created from the zone and serialized. Then upon de-serialization,
* the zone can be rebuilt, typically from a {@code readResolve} method.
* </p>
* @author Luc Maisonobe
* @since 7.1
*/
public class SphericalPolygonsSetTransferObject implements Serializable {
/** Serializable UID. */
private static final long serialVersionUID = 20150112L;
/** Tolerance for the zone. */
private final double tolerance;
/** Zone cut hyperplanes. */
private final double[] cuts;
/** Leaf nodes indices. */
private final int[] leafs;
/** Zone interior/exterior indicators. */
private final boolean[] flags;
/** Internal nodes counter. */
private transient int internalNodes;
/** Leaf nodes counter. */
private transient int leafNodes;
/** Node index. */
private transient int nodeIndex;
/** Index in cut hyperplanes array. */
private transient int cutIndex;
/** Index in interior/exterior flags array. */
private transient int flagIndex;
/** Simple constructor.
* @param zone zone to serialize
*/
public SphericalPolygonsSetTransferObject(final SphericalPolygonsSet zone) {
this.tolerance = zone.getTolerance();
// count the nodes
internalNodes = 0;
leafNodes = 0;
zone.getTree(false).visit(new BSPTreeVisitor<Sphere2D>() {
/** {@inheritDoc} */
public Order visitOrder(final BSPTree<Sphere2D> node) {
return Order.SUB_MINUS_PLUS;
}
/** {@inheritDoc} */
public void visitInternalNode(final BSPTree<Sphere2D> node) {
++internalNodes;
}
/** {@inheritDoc} */
public void visitLeafNode(final BSPTree<Sphere2D> node) {
++leafNodes;
}
});
// allocate the arrays for flattened tree
cuts = new double[3 * internalNodes];
leafs = new int[leafNodes];
flags = new boolean[leafNodes];
nodeIndex = 0;
cutIndex = 0;
flagIndex = 0;
zone.getTree(false).visit(new BSPTreeVisitor<Sphere2D>() {
/** {@inheritDoc} */
public Order visitOrder(final BSPTree<Sphere2D> node) {
return Order.SUB_MINUS_PLUS;
}
/** {@inheritDoc} */
public void visitInternalNode(final BSPTree<Sphere2D> node) {
final Vector3D cutPole = ((Circle) node.getCut().getHyperplane()).getPole();
cuts[cutIndex++] = cutPole.getX();
cuts[cutIndex++] = cutPole.getY();
cuts[cutIndex++] = cutPole.getZ();
nodeIndex++;
}
/** {@inheritDoc} */
public void visitLeafNode(final BSPTree<Sphere2D> node) {
leafs[flagIndex] = nodeIndex++;
flags[flagIndex++] = (Boolean) node.getAttribute();
}
});
}
/** Rebuild the zone from saved data.
* @return rebuilt zone
*/
public SphericalPolygonsSet rebuildZone() {
// rebuild the tree from the flattened arrays
BSPTree<Sphere2D> node = new BSPTree<Sphere2D>();
final int nbNodes = cuts.length / 3 + leafs.length;
cutIndex = 0;
flagIndex = 0;
for (nodeIndex = 0; nodeIndex < nbNodes; ++nodeIndex) {
if (leafs[flagIndex] == nodeIndex) {
// this is a leaf node
node.setAttribute(Boolean.valueOf(flags[flagIndex++]));
while (node.getParent() != null) {
final BSPTree<Sphere2D> parent = node.getParent();
if (node == parent.getMinus()) {
node = parent.getPlus();
break;
} else {
node = parent;
}
}
} else {
// this is an internal node
final double x = cuts[cutIndex++];
final double y = cuts[cutIndex++];
final double z = cuts[cutIndex++];
node.insertCut(new Circle(new Vector3D(x, y, z), tolerance));
node = node.getMinus();
}
}
return new SphericalPolygonsSet(node, tolerance);
}
}