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
18 package org.apache.commons.math4.legacy.linear;
19
20 import java.io.Serializable;
21
22 import org.apache.commons.math4.legacy.core.Field;
23 import org.apache.commons.math4.legacy.core.FieldElement;
24
25 /**
26 * Representation of real numbers with arbitrary precision field.
27 * <p>
28 * This class is a singleton.
29 * </p>
30 * @see BigReal
31 * @since 2.0
32 */
33 public final class BigRealField implements Field<BigReal>, Serializable {
34
35 /** Serializable version identifier. */
36 private static final long serialVersionUID = 4756431066541037559L;
37
38 /** Private constructor for the singleton.
39 */
40 private BigRealField() {
41 }
42
43 /** Get the unique instance.
44 * @return the unique instance
45 */
46 public static BigRealField getInstance() {
47 return LazyHolder.INSTANCE;
48 }
49
50 /** {@inheritDoc} */
51 @Override
52 public BigReal getOne() {
53 return BigReal.ONE;
54 }
55
56 /** {@inheritDoc} */
57 @Override
58 public BigReal getZero() {
59 return BigReal.ZERO;
60 }
61
62 /** {@inheritDoc} */
63 @Override
64 public Class<? extends FieldElement<BigReal>> getRuntimeClass() {
65 return BigReal.class;
66 }
67
68 // CHECKSTYLE: stop HideUtilityClassConstructor
69 /** Holder for the instance.
70 * <p>We use here the Initialization On Demand Holder Idiom.</p>
71 */
72 private static final class LazyHolder {
73 /** Cached field instance. */
74 private static final BigRealField INSTANCE = new BigRealField();
75 }
76 // CHECKSTYLE: resume HideUtilityClassConstructor
77
78 /** Handle deserialization of the singleton.
79 * @return the singleton instance
80 */
81 private Object readResolve() {
82 // return the singleton instance
83 return LazyHolder.INSTANCE;
84 }
85 }