    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
    018    package org.apache.commons.math3.geometry.euclidean.oned;
    019
    020    import java.io.Serializable;
    021
    022    import org.apache.commons.math3.exception.MathUnsupportedOperationException;
    023    import org.apache.commons.math3.exception.util.LocalizedFormats;
    024    import org.apache.commons.math3.geometry.Space;
    025
    026    /**
    027     * This class implements a one-dimensional space.
    028     * @version $Id: Euclidean1D.java 1416643 2012-12-03 19:37:14Z tn $
    029     * @since 3.0
    030     */
    031    public class Euclidean1D implements Serializable, Space {
    032
    033        /** Serializable version identifier. */
    034        private static final long serialVersionUID = -1178039568877797126L;
    035
    036        /** Private constructor for the singleton.
    037         */
    038        private Euclidean1D() {
    039        }
    040
    041        /** Get the unique instance.
    042         * @return the unique instance
    043         */
    044        public static Euclidean1D getInstance() {
    045            return LazyHolder.INSTANCE;
    046        }
    047
    048        /** {@inheritDoc} */
    049        public int getDimension() {
    050            return 1;
    051        }
    052
    053        /** {@inheritDoc}
    054         * <p>
    055         * As the 1-dimension Euclidean space does not have proper sub-spaces,
    056         * this method always throws a {@link MathUnsupportedOperationException}
    057         * </p>
    058         * @return nothing
    059         * @throws MathUnsupportedOperationException in all cases
    060         */
    061        public Space getSubSpace() throws MathUnsupportedOperationException {
    062            throw new MathUnsupportedOperationException(LocalizedFormats.NOT_SUPPORTED_IN_DIMENSION_N, 1);
    063        }
    064
    065        // CHECKSTYLE: stop HideUtilityClassConstructor
    066        /** Holder for the instance.
    067         * <p>We use here the Initialization On Demand Holder Idiom.</p>
    068         */
    069        private static class LazyHolder {
    070            /** Cached field instance. */
    071            private static final Euclidean1D INSTANCE = new Euclidean1D();
    072        }
    073        // CHECKSTYLE: resume HideUtilityClassConstructor
    074
    075        /** Handle deserialization of the singleton.
    076         * @return the singleton instance
    077         */
    078        private Object readResolve() {
    079            // return the singleton instance
    080            return LazyHolder.INSTANCE;
    081        }
    082
    083    }