/**
* Build an appropriate <code>Geometry</code>, <code>MultiGeometry</code>, or <code>
* GeometryCollection</code> to contain the <code>Geometry</code>s in it. For example:<br>
*
* <ul>
* <li>If <code>geomList</code> contains a single <code>Polygon</code>, the <code>Polygon</code>
* is returned.
* <li>If <code>geomList</code> contains several <code>Polygon</code>s, a <code>MultiPolygon
* </code> is returned.
* <li>If <code>geomList</code> contains some <code>Polygon</code>s and some <code>LineString
* </code>s, a <code>GeometryCollection</code> is returned.
* <li>If <code>geomList</code> is empty, an empty <code>GeometryCollection</code> is returned
* </ul>
*
* Note that this method does not "flatten" Geometries in the input, and hence if any
* MultiGeometries are contained in the input a GeometryCollection containing them will be
* returned.
*
* @param geomList the <code>Geometry</code>s to combine
* @return a <code>Geometry</code> of the "smallest", "most type-specific" class that can contain
* the elements of <code>geomList</code> .
*/
public Geometry buildGeometry(Collection geomList) {
/** Determine some facts about the geometries in the list */
Class geomClass = null;
boolean isHeterogeneous = false;
boolean hasGeometryCollection = false;
for (Iterator i = geomList.iterator(); i.hasNext(); ) {
Geometry geom = (Geometry) i.next();
Class partClass = geom.getClass();
if (geomClass == null) {
geomClass = partClass;
}
if (partClass != geomClass) {
isHeterogeneous = true;
}
if (geom instanceof GeometryCollection) hasGeometryCollection = true;
}
/** Now construct an appropriate geometry to return */
// for the empty geometry, return an empty GeometryCollection
if (geomClass == null) {
return createGeometryCollection(null);
}
if (isHeterogeneous || hasGeometryCollection) {
return createGeometryCollection(toGeometryArray(geomList));
}
// at this point we know the collection is hetereogenous.
// Determine the type of the result from the first Geometry in the list
// this should always return a geometry, since otherwise an empty collection would have already
// been returned
Geometry geom0 = (Geometry) geomList.iterator().next();
boolean isCollection = geomList.size() > 1;
if (isCollection) {
if (geom0 instanceof Polygon) {
return createMultiPolygon(toPolygonArray(geomList));
} else if (geom0 instanceof LineString) {
return createMultiLineString(toLineStringArray(geomList));
} else if (geom0 instanceof Point) {
return createMultiPoint(toPointArray(geomList));
}
Assert.shouldNeverReachHere("Unhandled class: " + geom0.getClass().getName());
}
return geom0;
}
/**
* Converts the <code>List</code> to an array.
*
* @param multiLineStrings the <code>List</code> of MultiLineStrings to convert
* @return the <code>List</code> in array format
*/
public static MultiLineString[] toMultiLineStringArray(Collection multiLineStrings) {
MultiLineString[] multiLineStringArray = new MultiLineString[multiLineStrings.size()];
return (MultiLineString[]) multiLineStrings.toArray(multiLineStringArray);
}
/**
* Converts the <code>List</code> to an array.
*
* @param multiPoints the <code>List</code> of MultiPoints to convert
* @return the <code>List</code> in array format
*/
public static MultiPoint[] toMultiPointArray(Collection multiPoints) {
MultiPoint[] multiPointArray = new MultiPoint[multiPoints.size()];
return (MultiPoint[]) multiPoints.toArray(multiPointArray);
}
/**
* Converts the <code>List</code> to an array.
*
* @param multiPolygons the <code>List</code> of MultiPolygons to convert
* @return the <code>List</code> in array format
*/
public static MultiPolygon[] toMultiPolygonArray(Collection multiPolygons) {
MultiPolygon[] multiPolygonArray = new MultiPolygon[multiPolygons.size()];
return (MultiPolygon[]) multiPolygons.toArray(multiPolygonArray);
}
/**
* Converts the <code>List</code> to an array.
*
* @param polygons the <code>List</code> of Polygons to convert
* @return the <code>List</code> in array format
*/
public static Polygon[] toPolygonArray(Collection polygons) {
Polygon[] polygonArray = new Polygon[polygons.size()];
return (Polygon[]) polygons.toArray(polygonArray);
}
/**
* Converts the <code>List</code> to an array.
*
* @param lineStrings the <code>List</code> of LineStrings to convert
* @return the <code>List</code> in array format
*/
public static LineString[] toLineStringArray(Collection lineStrings) {
LineString[] lineStringArray = new LineString[lineStrings.size()];
return (LineString[]) lineStrings.toArray(lineStringArray);
}
/**
* Converts the <code>List</code> to an array.
*
* @param geometries the list of <code>Geometry's</code> to convert
* @return the <code>List</code> in array format
*/
public static Geometry[] toGeometryArray(Collection geometries) {
if (geometries == null) return null;
Geometry[] geometryArray = new Geometry[geometries.size()];
return (Geometry[]) geometries.toArray(geometryArray);
}
/**
* Converts the <code>List</code> to an array.
*
* @param points the <code>List</code> of Points to convert
* @return the <code>List</code> in array format
*/
public static Point[] toPointArray(Collection points) {
Point[] pointArray = new Point[points.size()];
return (Point[]) points.toArray(pointArray);
}