Curve.java example

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geotools-old-master
/*
 *    OSGeom -- Geometry Collab
 *
 *    (C) 2009, Open Source Geospatial Foundation (OSGeo)
 *    (C) 2001-2009 Department of Geography, University of Bonn
 *    (C) 2001-2009 lat/lon GmbH
 *
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License as published by the Free Software Foundation;
 *    version 2.1 of the License.
 *
 *    This library is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *    Lesser General Public License for more details.
 */
package org.osgeo.geometry.primitive;

import java.util.List;

import org.osgeo.geometry.composite.CompositeCurve;
import org.osgeo.geometry.points.Points;
import org.osgeo.geometry.primitive.segments.CurveSegment;
import org.osgeo.geometry.primitive.segments.LineStringSegment;

/**
 * <code>Curve</code> instances are 1D-geometries that consist of an arbitrary number of curve segments.
 * 
 * @see CompositeCurve
 * @see LineString
 * @see OrientableCurve
 * @see Ring
 * 
 * @author <a href="mailto:poth@lat-lon.de">Andreas Poth</a>
 * @author last edited by: $Author$
 * 
 * @version. $Revision$, $Date$
 */
public interface Curve extends GeometricPrimitive {

    /**
     * Convenience enum type for discriminating the different curve variants.
     */
    public enum CurveType {
        /** Generic curve that consists of an arbitrary number of segments. */
        Curve,
        /** Curve that consists of a single segment with linear interpolation. */
        LineString,
        /** Curve that wraps a base curve with additional orientation flag. */
        OrientableCurve,
        /** Curve composited from multiple base curves. */
        CompositeCurve,
        /** A Ring consists of a sequence of curves connected in a cycle */
        Ring
    }

    /**
     * Must always return {@link GeometricPrimitive.PrimitiveType#Curve}.
     * 
     * @return {@link GeometricPrimitive.PrimitiveType#Curve}
     */
    public PrimitiveType getPrimitiveType();

    /**
     * Returns the type of curve.
     * 
     * @return the type of curve
     */
    public CurveType getCurveType();

    /**
     * Returns whether the curve forms a closed loop.
     * 
     * @return true, if the curve forms a closed loop, false otherwise
     */
    public boolean isClosed();

    /**
     * Returns the start point of the curve.
     * 
     * @return the start point of the curve
     */
    public Point getStartPoint();

    /**
     * Returns the end point of the curve.
     * 
     * @return the end point of the curve
     */
    public Point getEndPoint();

    /**
     * Returns the segments that constitute this curve.
     * 
     * @return the segments that constitute this curve
     */
    public List<CurveSegment> getCurveSegments();

    /**
     * Convenience method for accessing the control points of linear interpolated curves.
     * <p>
     * NOTE: This method is only safe to use when the curve is a {@link LineString} or {@link LinearRing} or it only
     * consists of {@link LineStringSegment}s. In any other case it will fail.
     * </p>
     * 
     * @return the control points
     * @throws IllegalArgumentException
     *             if the curve is not linear interpolated
     */
    public Points getControlPoints();

    /**
     * Returns a linear interpolated representation of the curve.
     * <p>
     * Please note that this operation returns an approximated version if the curve uses non-linear curve segments.
     * 
     * @return a linear interpolated representation of the curve
     */
    public LineString getAsLineString();
}