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Java > Open Source Codes > org > joda > time > field > SkipDateTimeField


1 /*
2  * Copyright 2001-2005 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 import org.joda.time.DateTimeFieldType;
21 import org.joda.time.IllegalFieldValueException;
22
23 /**
24  * Wraps another field such that a certain value is skipped.
25  * <p>
26  * This is most useful for years where you want to skip zero, so the
27  * sequence runs ...,2,1,-1,-2,...
28  * <p>
29  * SkipDateTimeField is thread-safe and immutable.
30  *
31  * @author Brian S O'Neill
32  * @author Stephen Colebourne
33  * @since 1.0
34  */
35 public final class SkipDateTimeField extends DelegatedDateTimeField {
36
37     /** Serialization version. */
38     private static final long serialVersionUID = -8869148464118507846L;
39
40     /** The chronology to wrap. */
41     private final Chronology iChronology;
42     /** The value to skip. */
43     private final int iSkip;
44     /** The calculated minimum value. */
45     private transient int iMinValue;
46
47     /**
48      * Constructor that skips zero.
49      *
50      * @param chronology the chronoogy to use
51      * @param field the field to skip zero on
52      */
53     public SkipDateTimeField(Chronology chronology, DateTimeField field) {
54         this(chronology, field, 0);
55     }
56
57     /**
58      * Constructor.
59      *
60      * @param chronology the chronoogy to use
61      * @param field the field to skip zero on
62      * @param skip the value to skip
63      */
64     public SkipDateTimeField(Chronology chronology, DateTimeField field, int skip) {
65         super(field);
66         iChronology = chronology;
67         int min = super.getMinimumValue();
68         if (min < skip) {
69             iMinValue = min - 1;
70         } else if (min == skip) {
71             iMinValue = skip + 1;
72         } else {
73             iMinValue = min;
74         }
75         iSkip = skip;
76     }
77
78     //-----------------------------------------------------------------------
79 public int get(long millis) {
80         int value = super.get(millis);
81         if (value <= iSkip) {
82             value--;
83         }
84         return value;
85     }
86
87     public long set(long millis, int value) {
88         FieldUtils.verifyValueBounds(this, value, iMinValue, getMaximumValue());
89         if (value <= iSkip) {
90             if (value == iSkip) {
91                 throw new IllegalFieldValueException
92                     (DateTimeFieldType.year(), new Integer JavaDoc(value), null, null);
93             }
94             value++;
95         }
96         return super.set(millis, value);
97     }
98
99     public int getMinimumValue() {
100         return iMinValue;
101     }
102
103     private Object JavaDoc readResolve() {
104         return getType().getField(iChronology);
105     }
106
107 }
108
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