| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.apache.commons.math.fraction; |
| |
| import java.io.Serializable; |
| |
| import org.apache.commons.math.Field; |
| |
| /** |
| * Representation of the fractional numbers field. |
| * <p> |
| * This class is a singleton. |
| * </p> |
| * @see Fraction |
| * @version $Revision: 811827 $ $Date: 2009-09-06 17:32:50 +0200 (dim. 06 sept. 2009) $ |
| * @since 2.0 |
| */ |
| public class FractionField implements Field<Fraction>, Serializable { |
| |
| /** Serializable version identifier */ |
| private static final long serialVersionUID = -1257768487499119313L; |
| |
| /** Private constructor for the singleton. |
| */ |
| private FractionField() { |
| } |
| |
| /** Get the unique instance. |
| * @return the unique instance |
| */ |
| public static FractionField getInstance() { |
| return LazyHolder.INSTANCE; |
| } |
| |
| /** {@inheritDoc} */ |
| public Fraction getOne() { |
| return Fraction.ONE; |
| } |
| |
| /** {@inheritDoc} */ |
| public Fraction getZero() { |
| return Fraction.ZERO; |
| } |
| |
| // CHECKSTYLE: stop HideUtilityClassConstructor |
| /** Holder for the instance. |
| * <p>We use here the Initialization On Demand Holder Idiom.</p> |
| */ |
| private static class LazyHolder { |
| /** Cached field instance. */ |
| private static final FractionField INSTANCE = new FractionField(); |
| } |
| // CHECKSTYLE: resume HideUtilityClassConstructor |
| |
| /** Handle deserialization of the singleton. |
| * @return the singleton instance |
| */ |
| private Object readResolve() { |
| // return the singleton instance |
| return LazyHolder.INSTANCE; |
| } |
| |
| } |