    001    /*
    002     * Licensed to the Apache Software Foundation (ASF) under one or more
    003     * contributor license agreements.  See the NOTICE file distributed with
    004     * this work for additional information regarding copyright ownership.
    005     * The ASF licenses this file to You under the Apache License, Version 2.0
    006     * (the "License"); you may not use this file except in compliance with
    007     * the License.  You may obtain a copy of the License at
    008     *
    009     *      http://www.apache.org/licenses/LICENSE-2.0
    010     *
    011     * Unless required by applicable law or agreed to in writing, software
    012     * distributed under the License is distributed on an "AS IS" BASIS,
    013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014     * See the License for the specific language governing permissions and
    015     * limitations under the License.
    016     */
    017    package org.apache.commons.math3.geometry.euclidean.oned;
    018
    019    import org.apache.commons.math3.geometry.Vector;
    020    import org.apache.commons.math3.geometry.partitioning.Hyperplane;
    021
    022    /** This class represents a 1D oriented hyperplane.
    023     * <p>An hyperplane in 1D is a simple point, its orientation being a
    024     * boolean.</p>
    025     * <p>Instances of this class are guaranteed to be immutable.</p>
    026     * @version $Id: OrientedPoint.java 1416643 2012-12-03 19:37:14Z tn $
    027     * @since 3.0
    028     */
    029    public class OrientedPoint implements Hyperplane<Euclidean1D> {
    030
    031        /** Vector location. */
    032        private Vector1D location;
    033
    034        /** Orientation. */
    035        private boolean direct;
    036
    037        /** Simple constructor.
    038         * @param location location of the hyperplane
    039         * @param direct if true, the plus side of the hyperplane is towards
    040         * abscissas greater than {@code location}
    041         */
    042        public OrientedPoint(final Vector1D location, final boolean direct) {
    043            this.location = location;
    044            this.direct   = direct;
    045        }
    046
    047        /** Copy the instance.
    048         * <p>Since instances are immutable, this method directly returns
    049         * the instance.</p>
    050         * @return the instance itself
    051         */
    052        public OrientedPoint copySelf() {
    053            return this;
    054        }
    055
    056        /** {@inheritDoc} */
    057        public double getOffset(final Vector<Euclidean1D> point) {
    058            final double delta = ((Vector1D) point).getX() - location.getX();
    059            return direct ? delta : -delta;
    060        }
    061
    062        /** Build a region covering the whole hyperplane.
    063         * <p>Since this class represent zero dimension spaces which does
    064         * not have lower dimension sub-spaces, this method returns a dummy
    065         * implementation of a {@link
    066         * org.apache.commons.math3.geometry.partitioning.SubHyperplane SubHyperplane}.
    067         * This implementation is only used to allow the {@link
    068         * org.apache.commons.math3.geometry.partitioning.SubHyperplane
    069         * SubHyperplane} class implementation to work properly, it should
    070         * <em>not</em> be used otherwise.</p>
    071         * @return a dummy sub hyperplane
    072         */
    073        public SubOrientedPoint wholeHyperplane() {
    074            return new SubOrientedPoint(this, null);
    075        }
    076
    077        /** Build a region covering the whole space.
    078         * @return a region containing the instance (really an {@link
    079         * IntervalsSet IntervalsSet} instance)
    080         */
    081        public IntervalsSet wholeSpace() {
    082            return new IntervalsSet();
    083        }
    084
    085        /** {@inheritDoc} */
    086        public boolean sameOrientationAs(final Hyperplane<Euclidean1D> other) {
    087            return !(direct ^ ((OrientedPoint) other).direct);
    088        }
    089
    090        /** Get the hyperplane location on the real line.
    091         * @return the hyperplane location
    092         */
    093        public Vector1D getLocation() {
    094            return location;
    095        }
    096
    097        /** Check if the hyperplane orientation is direct.
    098         * @return true if the plus side of the hyperplane is towards
    099         * abscissae greater than hyperplane location
    100         */
    101        public boolean isDirect() {
    102            return direct;
    103        }
    104
    105        /** Revert the instance.
    106         */
    107        public void revertSelf() {
    108            direct = !direct;
    109        }
    110
    111    }