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.threed; 019 020 import java.io.Serializable; 021 022 import org.apache.commons.math3.geometry.Space; 023 import org.apache.commons.math3.geometry.euclidean.twod.Euclidean2D; 024 025 /** 026 * This class implements a three-dimensional space. 027 * @version $Id: Euclidean3D.java 1416643 2012-12-03 19:37:14Z tn $ 028 * @since 3.0 029 */ 030 public class Euclidean3D implements Serializable, Space { 031 032 /** Serializable version identifier. */ 033 private static final long serialVersionUID = 6249091865814886817L; 034 035 /** Private constructor for the singleton. 036 */ 037 private Euclidean3D() { 038 } 039 040 /** Get the unique instance. 041 * @return the unique instance 042 */ 043 public static Euclidean3D getInstance() { 044 return LazyHolder.INSTANCE; 045 } 046 047 /** {@inheritDoc} */ 048 public int getDimension() { 049 return 3; 050 } 051 052 /** {@inheritDoc} */ 053 public Euclidean2D getSubSpace() { 054 return Euclidean2D.getInstance(); 055 } 056 057 // CHECKSTYLE: stop HideUtilityClassConstructor 058 /** Holder for the instance. 059 * <p>We use here the Initialization On Demand Holder Idiom.</p> 060 */ 061 private static class LazyHolder { 062 /** Cached field instance. */ 063 private static final Euclidean3D INSTANCE = new Euclidean3D(); 064 } 065 // CHECKSTYLE: resume HideUtilityClassConstructor 066 067 /** Handle deserialization of the singleton. 068 * @return the singleton instance 069 */ 070 private Object readResolve() { 071 // return the singleton instance 072 return LazyHolder.INSTANCE; 073 } 074 075 }