1/*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements.  See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License.  You may obtain a copy of the License at
8 *
9 *      http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18package org.apache.commons.math.fraction;
19
20import java.io.Serializable;
21
22import org.apache.commons.math.Field;
23
24/**
25 * Representation of the fractional numbers  without any overflow field.
26 * <p>
27 * This class is a singleton.
28 * </p>
29 * @see Fraction
30 * @version $Revision: 811827 $ $Date: 2009-09-06 17:32:50 +0200 (dim. 06 sept. 2009) $
31 * @since 2.0
32 */
33public class BigFractionField implements Field<BigFraction>, Serializable  {
34
35    /** Serializable version identifier */
36    private static final long serialVersionUID = -1699294557189741703L;
37
38    /** Private constructor for the singleton.
39     */
40    private BigFractionField() {
41    }
42
43    /** Get the unique instance.
44     * @return the unique instance
45     */
46    public static BigFractionField getInstance() {
47        return LazyHolder.INSTANCE;
48    }
49
50    /** {@inheritDoc} */
51    public BigFraction getOne() {
52        return BigFraction.ONE;
53    }
54
55    /** {@inheritDoc} */
56    public BigFraction getZero() {
57        return BigFraction.ZERO;
58    }
59
60    // CHECKSTYLE: stop HideUtilityClassConstructor
61    /** Holder for the instance.
62     * <p>We use here the Initialization On Demand Holder Idiom.</p>
63     */
64    private static class LazyHolder {
65        /** Cached field instance. */
66        private static final BigFractionField INSTANCE = new BigFractionField();
67    }
68    // CHECKSTYLE: resume HideUtilityClassConstructor
69
70    /** Handle deserialization of the singleton.
71     * @return the singleton instance
72     */
73    private Object readResolve() {
74        // return the singleton instance
75        return LazyHolder.INSTANCE;
76    }
77
78}
79