/*$************************************************************************************************
 **
 ** $Id: Ring.java 831 2006-05-01 00:27:23Z Desruisseaux $
 **
 ** $URL: http://svn.code.sf.net/p/geoapi/code/branches/2.0.x/geoapi/src/main/java/org/opengis/spatialschema/geometry/primitive/Ring.java $
 **
 ** Copyright (C) 2003-2005 Open GIS Consortium, Inc.
 ** All Rights Reserved. http://www.opengis.org/legal/
 **
 *************************************************************************************************/
package org.opengis.spatialschema.geometry.primitive;

// OpenGIS direct dependencies
import org.opengis.spatialschema.geometry.complex.CompositeCurve;

// Annotations
import org.opengis.annotation.UML;
import static org.opengis.annotation.Obligation.*;
import static org.opengis.annotation.Specification.*;


/**
 * Represent a single connected component of a {@linkplain SurfaceBoundary surface boundary}.
 * It consists of a number of references to {@linkplain OrientableCurve orientable curves}
 * connected in a cycle (an object whose boundary is empty). A {@code Ring} is structurally
 * similar to a {@linkplain CompositeCurve composite curve} in that the end point of each
 * {@linkplain OrientableCurve orientable curve} in the sequence is the start point of the next
 * {@linkplain OrientableCurve orientable curve} in the sequence. Since the sequence is circular,
 * there is no exception to this rule. Each ring, like all boundaries is a cycle and each ring is
 * simple.
 * 

 * Even though each {@code Ring} is simple, the boundary need not be simple. The easiest
 * case of this is where one of the interior rings of a surface is tangent to its exterior ring.
 * Implementations may enforce stronger restrictions on the interaction of boundary elements.
 *
 * @version Abstract specification 5
 * @author Martin Desruisseaux (IRD)
 * @since GeoAPI 1.0
 *
 * @see SurfaceBoundary
 * @see Shell
 */
@UML(identifier="GM_Ring", specification=ISO_19107)
public interface Ring extends CompositeCurve {
    /**
     * Always returns {@code true} since ring objects are simples.
     *
     * @return Always {@code true}.
     */
    public boolean isSimple();
}