1 /*
2 * Copyright 2001-2007 Stephen Colebourne
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 package org.joda.time.field;
17
18 import org.joda.time.Chronology;
19 import org.joda.time.DateTimeField;
20
21 /**
22 * Converts a strict DateTimeField into a lenient one. By being lenient, the
23 * set method accepts out of bounds values, performing an addition instead.
24 * <p>
25 * LenientDateTimeField is thread-safe and immutable.
26 *
27 * @author Brian S O'Neill
28 * @see org.joda.time.chrono.LenientChronology
29 * @see StrictDateTimeField
30 * @since 1.0
31 */
32 public class LenientDateTimeField extends DelegatedDateTimeField {
33
34 private static final long serialVersionUID = 8714085824173290599L;
35
36 private final Chronology iBase;
37
38 /**
39 * Returns a lenient version of the given field. If it is already lenient,
40 * then it is returned as-is. Otherwise, a new LenientDateTimeField is
41 * returned.
42 */
43 public static DateTimeField getInstance(DateTimeField field, Chronology base) {
44 if (field == null) {
45 return null;
46 }
47 if (field instanceof StrictDateTimeField) {
48 field = ((StrictDateTimeField)field).getWrappedField();
49 }
50 if (field.isLenient()) {
51 return field;
52 }
53 return new LenientDateTimeField(field, base);
54 }
55
56 protected LenientDateTimeField(DateTimeField field, Chronology base) {
57 super(field);
58 iBase = base;
59 }
60
61 public final boolean isLenient() {
62 return true;
63 }
64
65 /**
66 * Set values which may be out of bounds by adding the difference between
67 * the new value and the current value.
68 */
69 public long set(long instant, int value) {
70 // lenient needs to handle time zone chronologies
71 // so we do the calculation using local milliseconds
72 long localInstant = iBase.getZone().convertUTCToLocal(instant);
73 long difference = FieldUtils.safeSubtract(value, get(instant));
74 localInstant = getType().getField(iBase.withUTC()).add(localInstant, difference);
75 return iBase.getZone().convertLocalToUTC(localInstant, false, instant);
76 }
77 }