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
018package org.apache.commons.math3.complex;
019
020import java.io.Serializable;
021
022import org.apache.commons.math3.Field;
023import org.apache.commons.math3.FieldElement;
024
025/**
026 * Representation of the complex numbers field.
027 * <p>
028 * This class is a singleton.
029 * </p>
030 * @see Complex
031 * @since 2.0
032 */
033public class ComplexField implements Field<Complex>, Serializable  {
034
035    /** Serializable version identifier. */
036    private static final long serialVersionUID = -6130362688700788798L;
037
038    /** Private constructor for the singleton.
039     */
040    private ComplexField() {
041    }
042
043    /** Get the unique instance.
044     * @return the unique instance
045     */
046    public static ComplexField getInstance() {
047        return LazyHolder.INSTANCE;
048    }
049
050    /** {@inheritDoc} */
051    public Complex getOne() {
052        return Complex.ONE;
053    }
054
055    /** {@inheritDoc} */
056    public Complex getZero() {
057        return Complex.ZERO;
058    }
059
060    /** {@inheritDoc} */
061    public Class<? extends FieldElement<Complex>> getRuntimeClass() {
062        return Complex.class;
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 ComplexField INSTANCE = new ComplexField();
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}