1 /*
2 *******************************************************************************
3 * Copyright (C) 2008, Google, International Business Machines Corporation and *
4 * others. All Rights Reserved. *
5 *******************************************************************************
6 */
7
8 #include "unicode/tmunit.h"
9
10 #if !UCONFIG_NO_FORMATTING
11
12 U_NAMESPACE_BEGIN
13
UOBJECT_DEFINE_RTTI_IMPLEMENTATION(TimeUnit)14 UOBJECT_DEFINE_RTTI_IMPLEMENTATION(TimeUnit)
15
16
17 /*
18 * There are only 7 time units.
19 * So, TimeUnit could be made as singleton
20 * (similar to uniset_props.cpp, or unorm.cpp,
21 * in which a static TimeUnit* array is created, and
22 * the creatInstance() returns a const TimeUnit*).
23 * But the constraint is TimeUnit is a data member of Measure.
24 * But Measure (which is an existing API) does not expect it's "unit" member
25 * as singleton. Meaure takes ownership of the "unit" member.
26 * In its constructor, it does not take a const "unit" pointer.
27 * Also, Measure can clone and destruct the "unit" pointer.
28 * In order to preserve the old behavior and let Measure handle singleton "unit",
29 * 1. a flag need to be added in Measure;
30 * 2. a new constructor which takes const "unit" as parameter need to be added,
31 * and this new constructor will set the flag on.
32 * 3. clone and destructor need to check upon this flag to distinguish on how
33 * to handle the "unit".
34 *
35 * Since TimeUnit is such a light weight object, comparing with the heavy weight
36 * format operation, we decided to avoid the above complication.
37 *
38 * So, both TimeUnit and CurrencyUnit (the 2 subclasses of MeasureUnit) are
39 * immutable and non-singleton.
40 *
41 * Currently, TimeUnitAmount and CurrencyAmount are immutable.
42 * If an application needs to create a long list of TimeUnitAmount on the same
43 * time unit but different number, for example,
44 * 1 hour, 2 hour, 3 hour, ................. 10,000 hour,
45 * there might be performance hit because 10,000 TimeUnit object,
46 * although all are the same time unit, will be created in heap and deleted.
47 *
48 * To address this performance issue, if there is any in the future,
49 * we should and need to change TimeUnitAmount and CurrencyAmount to be
50 * immutable by allowing a setter on the number.
51 * Or we need to add 2 parallel mutable classes in order to
52 * preserve the existing API.
53 * Or we can use freezable.
54 */
55 TimeUnit* U_EXPORT2
56 TimeUnit::createInstance(TimeUnit::UTimeUnitFields timeUnitField,
57 UErrorCode& status) {
58 if (U_FAILURE(status)) {
59 return NULL;
60 }
61 if (timeUnitField < 0 || timeUnitField >= UTIMEUNIT_FIELD_COUNT) {
62 status = U_ILLEGAL_ARGUMENT_ERROR;
63 return NULL;
64 }
65 return new TimeUnit(timeUnitField);
66 }
67
68
TimeUnit(TimeUnit::UTimeUnitFields timeUnitField)69 TimeUnit::TimeUnit(TimeUnit::UTimeUnitFields timeUnitField) {
70 fTimeUnitField = timeUnitField;
71 }
72
73
TimeUnit(const TimeUnit & other)74 TimeUnit::TimeUnit(const TimeUnit& other)
75 : MeasureUnit(other) {
76 *this = other;
77 }
78
79
80 UObject*
clone() const81 TimeUnit::clone() const {
82 return new TimeUnit(*this);
83 }
84
85
86 TimeUnit&
operator =(const TimeUnit & other)87 TimeUnit::operator=(const TimeUnit& other) {
88 if (this == &other) {
89 return *this;
90 }
91 fTimeUnitField = other.fTimeUnitField;
92 return *this;
93 }
94
95
96 UBool
operator ==(const UObject & other) const97 TimeUnit::operator==(const UObject& other) const {
98 return (other.getDynamicClassID() == TimeUnit::getStaticClassID()
99 && fTimeUnitField == ((TimeUnit*)&other)->fTimeUnitField);
100 }
101
102
103 TimeUnit::UTimeUnitFields
getTimeUnitField() const104 TimeUnit::getTimeUnitField() const {
105 return fTimeUnitField;
106 }
107
108
~TimeUnit()109 TimeUnit::~TimeUnit() {
110 }
111
112
113 U_NAMESPACE_END
114
115 #endif
116