/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *
 *    (C) 2011, Open Source Geospatial Foundation (OSGeo)
 *    (C) 2003-2005, Open Geospatial Consortium Inc.
 *    
 *    All Rights Reserved. http://www.opengis.org/legal/
 */
package org.opengis.geometry.primitive;

import org.opengis.geometry.coordinate.GenericSurface;
import org.opengis.annotation.Association;
import org.opengis.annotation.UML;

import static org.opengis.annotation.Obligation.*;
import static org.opengis.annotation.Specification.*;


/**
 * Defines a homogeneous portion of a {@linkplain Surface surface}.
 * Each {@code SurfacePatch} shall be in at most one {@linkplain Surface surface}.
 *
 *
 * @source $URL: http://svn.osgeo.org/geotools/trunk/modules/library/opengis/src/main/java/org/opengis/geometry/primitive/SurfacePatch.java $
 * @version <A HREF="http://www.opengeospatial.org/standards/as">ISO 19107</A>
 * @author Martin Desruisseaux (IRD)
 * @since GeoAPI 1.0
 */
@UML(identifier="GM_SurfacePatch", specification=ISO_19107)
public interface SurfacePatch extends GenericSurface {
    /**
     * Returns the patch which own this surface patch. This method is <em>optional</em> since the
     * association in ISO 19107 is navigable only from {@code Surface} to {@code SurfacePatch},
     * not the other way.
     *
     * <blockquote><font size=2>
     * <strong>NOTE:</strong> In the specification, surface patches do not appear except in the
     * context of a surface, and therefore this method should never returns {@code null} which
     * would preclude the use of surface patches except in this manner. While this would not
     * affect the specification, allowing {@code null} owner allows other standards based on
     * ISO 19107 one to use surface patches in a more open-ended manner.
     * </font></blockquote>
     *
     * @return The owner of this surface patch, or {@code null} if the association is
     *         not available or not implemented that way.
     *
     * @see Surface#getPatches
     * @see CurveSegment#getCurve
     * @issue http://jira.codehaus.org/browse/GEO-63
     */
    @Association("Segmentation")
    @UML(identifier="surface", obligation=OPTIONAL, specification=ISO_19107)
    Surface getSurface();

    /**
     * Determines the surface interpolation mechanism used for this {@code SurfacePatch}.
     * This mechanism uses the control points and control parameters defined in the various
     * subclasses to determine the position of this {@code SurfacePatch}.
     *
     * @return The interpolation mechanism.
     */
    @UML(identifier="interpolation", obligation=MANDATORY, specification=ISO_19107)
    SurfaceInterpolation getInterpolation();

    /**
     * Specifies the type of continuity between this surface patch and its immediate neighbors
     * with which it shares a boundary curve. The sequence of values corresponds to the
     * {@linkplain Ring rings} in the {@linkplain SurfaceBoundary surface boundary} returned by
     * {@link #getBoundary} for this patch. The default value of "0" means simple continuity, which
     * is a mandatory minimum level of continuity. This level is referred to as "C<sup>0</sup>" in
     * mathematical texts. A value of 1 means that the functions are continuous and differentiable
     * at the appropriate end point: "C<sup>1</sup>" continuity. A value of "n" for any integer means
     * <var>n</var>-times differentiable: "C<sup>n</sup>" continuity.
     *
     * @return The type of continuity between this surface patch and its immediate neighbors.
     */
    @UML(identifier="numDerivativesOnBoundary", obligation=MANDATORY, specification=ISO_19107)
    int getNumDerivativesOnBoundary();

    /**
     * Returns the boundary of this {@code SurfacePatch} represented as a collection of
     * {@linkplain OrientableCurve orientable curves} organized into {@linkplain Ring rings}
     * by a {@linkplain SurfaceBoundary surface boundary}. The semantics of this operation is
     * the same as that of {@link Surface#getBoundary()}, except that the curves used here may
     * be not be persistent {@linkplain OrientableCurve orientable curve} instances. Transient
     * data type values of {@linkplain Curve curve} are also valid. In the normal case,
     * {@code SurfacePatch}es will share parts of their boundary with the aggregate
     * {@linkplain Surface surface}, and other parts with {@code SurfacePatch}es (not
     * necessarily distinct).
     *
     * @return The boundary of this {@code SurfacePatch}
     */
    @UML(identifier="boundary", obligation=MANDATORY, specification=ISO_19107)
    SurfaceBoundary getBoundary();
}