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 java.math;
19 
20 /**
21  * Specifies the rounding behavior for operations whose results cannot be
22  * represented exactly.
23  */
24 public enum RoundingMode {
25 
26     /**
27      * Rounding mode where positive values are rounded towards positive infinity
28      * and negative values towards negative infinity.
29      * <br>
30      * Rule: {@code x.round().abs() >= x.abs()}
31      */
32     UP(BigDecimal.ROUND_UP),
33 
34     /**
35      * Rounding mode where the values are rounded towards zero.
36      * <br>
37      * Rule: {@code x.round().abs() <= x.abs()}
38      */
39     DOWN(BigDecimal.ROUND_DOWN),
40 
41     /**
42      * Rounding mode to round towards positive infinity. For positive values
43      * this rounding mode behaves as {@link #UP}, for negative values as
44      * {@link #DOWN}.
45      * <br>
46      * Rule: {@code x.round() >= x}
47      */
48     CEILING(BigDecimal.ROUND_CEILING),
49 
50     /**
51      * Rounding mode to round towards negative infinity. For positive values
52      * this rounding mode behaves as {@link #DOWN}, for negative values as
53      * {@link #UP}.
54      * <br>
55      * Rule: {@code x.round() <= x}
56      */
57     FLOOR(BigDecimal.ROUND_FLOOR),
58 
59     /**
60      * Rounding mode where values are rounded towards the nearest neighbor. Ties
61      * are broken by rounding up.
62      */
63     HALF_UP(BigDecimal.ROUND_HALF_UP),
64 
65     /**
66      * Rounding mode where values are rounded towards the nearest neighbor. Ties
67      * are broken by rounding down.
68      */
69     HALF_DOWN(BigDecimal.ROUND_HALF_DOWN),
70 
71     /**
72      * Rounding mode where values are rounded towards the nearest neighbor. Ties
73      * are broken by rounding to the even neighbor.
74      */
75     HALF_EVEN(BigDecimal.ROUND_HALF_EVEN),
76 
77     /**
78      * Rounding mode where the rounding operations throws an ArithmeticException
79      * for the case that rounding is necessary, i.e. for the case that the value
80      * cannot be represented exactly.
81      */
82     UNNECESSARY(BigDecimal.ROUND_UNNECESSARY);
83 
84     /** The old constant of <code>BigDecimal</code>. */
85     private final int bigDecimalRM;
86 
87     /** It sets the old constant. */
RoundingMode(int rm)88     RoundingMode(int rm) {
89         bigDecimalRM = rm;
90     }
91 
92     /**
93      * Converts rounding mode constants from class {@code BigDecimal} into
94      * {@code RoundingMode} values.
95      *
96      * @param mode
97      *            rounding mode constant as defined in class {@code BigDecimal}
98      * @return corresponding rounding mode object
99      */
valueOf(int mode)100     public static RoundingMode valueOf(int mode) {
101         switch (mode) {
102             case BigDecimal.ROUND_CEILING:
103                 return CEILING;
104             case BigDecimal.ROUND_DOWN:
105                 return DOWN;
106             case BigDecimal.ROUND_FLOOR:
107                 return FLOOR;
108             case BigDecimal.ROUND_HALF_DOWN:
109                 return HALF_DOWN;
110             case BigDecimal.ROUND_HALF_EVEN:
111                 return HALF_EVEN;
112             case BigDecimal.ROUND_HALF_UP:
113                 return HALF_UP;
114             case BigDecimal.ROUND_UNNECESSARY:
115                 return UNNECESSARY;
116             case BigDecimal.ROUND_UP:
117                 return UP;
118             default:
119                 throw new IllegalArgumentException("Invalid rounding mode");
120         }
121     }
122 }
123