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.util;
019    
020    import java.io.Serializable;
021    
022    import org.apache.commons.math3.Field;
023    import org.apache.commons.math3.FieldElement;
024    
025    /**
026     * Representation of real numbers with arbitrary precision field.
027     * <p>
028     * This class is a singleton.
029     * </p>
030     * @see BigReal
031     * @version $Id: BigRealField.java 1416643 2012-12-03 19:37:14Z tn $
032     * @since 2.0
033     */
034    public class BigRealField implements Field<BigReal>, Serializable  {
035    
036        /** Serializable version identifier */
037        private static final long serialVersionUID = 4756431066541037559L;
038    
039        /** Private constructor for the singleton.
040         */
041        private BigRealField() {
042        }
043    
044        /** Get the unique instance.
045         * @return the unique instance
046         */
047        public static BigRealField getInstance() {
048            return LazyHolder.INSTANCE;
049        }
050    
051        /** {@inheritDoc} */
052        public BigReal getOne() {
053            return BigReal.ONE;
054        }
055    
056        /** {@inheritDoc} */
057        public BigReal getZero() {
058            return BigReal.ZERO;
059        }
060    
061        /** {@inheritDoc} */
062        public Class<? extends FieldElement<BigReal>> getRuntimeClass() {
063            return BigReal.class;
064        }
065    
066        // CHECKSTYLE: stop HideUtilityClassConstructor
067        /** Holder for the instance.
068         * <p>We use here the Initialization On Demand Holder Idiom.</p>
069         */
070        private static class LazyHolder {
071            /** Cached field instance. */
072            private static final BigRealField INSTANCE = new BigRealField();
073        }
074        // CHECKSTYLE: resume HideUtilityClassConstructor
075    
076        /** Handle deserialization of the singleton.
077         * @return the singleton instance
078         */
079        private Object readResolve() {
080            // return the singleton instance
081            return LazyHolder.INSTANCE;
082        }
083    
084    }