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.complex;
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 the complex numbers field.
027 * <p>
028 * This class is a singleton.
029 * </p>
030 * @see Complex
031 * @version $Id: ComplexField.java 1416643 2012-12-03 19:37:14Z tn $
032 * @since 2.0
033 */
034 public class ComplexField implements Field<Complex>, Serializable {
035
036 /** Serializable version identifier. */
037 private static final long serialVersionUID = -6130362688700788798L;
038
039 /** Private constructor for the singleton.
040 */
041 private ComplexField() {
042 }
043
044 /** Get the unique instance.
045 * @return the unique instance
046 */
047 public static ComplexField getInstance() {
048 return LazyHolder.INSTANCE;
049 }
050
051 /** {@inheritDoc} */
052 public Complex getOne() {
053 return Complex.ONE;
054 }
055
056 /** {@inheritDoc} */
057 public Complex getZero() {
058 return Complex.ZERO;
059 }
060
061 /** {@inheritDoc} */
062 public Class<? extends FieldElement<Complex>> getRuntimeClass() {
063 return Complex.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 ComplexField INSTANCE = new ComplexField();
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 }