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[MATH-749] Change the way the line segments are computed as they can not be serialized. Use the array only as cache and create them as needed. 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1566064 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Thomas Neidhart 2014-02-08 17:44:37 +00:00
parent c92f7d0c8f
commit 3c644cf87e
1 changed files with 52 additions and 36 deletions
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88
src/main/java/org/apache/commons/math3/geometry/euclidean/twod/hull/ConvexHull2D.java
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@ -18,7 +18,6 @@ package org.apache.commons.math3.geometry.euclidean.twod.hull;
import java.io.Serializable;
import java.util.Collection;
import java.util.Iterator;
import org.apache.commons.math3.exception.InsufficientDataException;
import org.apache.commons.math3.geometry.euclidean.twod.Euclidean2D;
@ -43,8 +42,14 @@ public class ConvexHull2D implements ConvexHull<Euclidean2D, Vector2D>, Serializ
/** Vertices of the hull. */
private final Vector2D[] vertices;
/** Line segments of the hull. */
private final Segment[] lineSegments;
/** Tolerance threshold used during creation of the hull vertices. */
private final double tolerance;
/**
* Line segments of the hull.
* The array is not serialized and will be created from the vertices on first access.
*/
private transient Segment[] lineSegments;
/**
* Simple constructor.
@ -53,35 +58,7 @@ public class ConvexHull2D implements ConvexHull<Euclidean2D, Vector2D>, Serializ
*/
ConvexHull2D(final Collection<Vector2D> vertices, final double tolerance) {
this.vertices = vertices.toArray(new Vector2D[vertices.size()]);
// construct the line segments - handle special cases of 1 or 2 points
final int size = vertices.size();
if (size <= 1) {
this.lineSegments = new Segment[0];
} else if (size == 2) {
this.lineSegments = new Segment[1];
final Iterator<Vector2D> it = vertices.iterator();
final Vector2D p1 = it.next();
final Vector2D p2 = it.next();
this.lineSegments[0] = new Segment(p1, p2, new Line(p1, p2, tolerance));
} else {
this.lineSegments = new Segment[size];
Vector2D firstPoint = null;
Vector2D lastPoint = null;
int index = 0;
for (Vector2D point : vertices) {
if (lastPoint == null) {
firstPoint = point;
lastPoint = point;
} else {
this.lineSegments[index++] =
new Segment(lastPoint, point, new Line(lastPoint, point, tolerance));
lastPoint = point;
}
}
this.lineSegments[index] =
new Segment(lastPoint, firstPoint, new Line(lastPoint, firstPoint, tolerance));
}
this.tolerance = tolerance;
}
/** {@inheritDoc} */
@ -94,7 +71,45 @@ public class ConvexHull2D implements ConvexHull<Euclidean2D, Vector2D>, Serializ
* @return the line segments of the convex hull
*/
public Segment[] getLineSegments() {
return lineSegments.clone();
return retrieveLineSegments().clone();
}
/**
* Retrieve the line segments from the cached array or create them if needed.
*
* @return the array of line segments
*/
private Segment[] retrieveLineSegments() {
if (lineSegments == null) {
// construct the line segments - handle special cases of 1 or 2 points
final int size = vertices.length;
if (size <= 1) {
this.lineSegments = new Segment[0];
} else if (size == 2) {
this.lineSegments = new Segment[1];
final Vector2D p1 = vertices[0];
final Vector2D p2 = vertices[1];
this.lineSegments[0] = new Segment(p1, p2, new Line(p1, p2, tolerance));
} else {
this.lineSegments = new Segment[size];
Vector2D firstPoint = null;
Vector2D lastPoint = null;
int index = 0;
for (Vector2D point : vertices) {
if (lastPoint == null) {
firstPoint = point;
lastPoint = point;
} else {
this.lineSegments[index++] =
new Segment(lastPoint, point, new Line(lastPoint, point, tolerance));
lastPoint = point;
}
}
this.lineSegments[index] =
new Segment(lastPoint, firstPoint, new Line(lastPoint, firstPoint, tolerance));
}
}
return lineSegments;
}
/** {@inheritDoc} */
@ -103,9 +118,10 @@ public class ConvexHull2D implements ConvexHull<Euclidean2D, Vector2D>, Serializ
throw new InsufficientDataException();
}
final RegionFactory<Euclidean2D> factory = new RegionFactory<Euclidean2D>();
final Line[] lineArray = new Line[lineSegments.length];
for (int i = 0; i < lineSegments.length; i++) {
lineArray[i] = lineSegments[i].getLine();
final Segment[] segments = retrieveLineSegments();
final Line[] lineArray = new Line[segments.length];
for (int i = 0; i < segments.length; i++) {
lineArray[i] = segments[i].getLine();
}
return factory.buildConvex(lineArray);
}