1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
package common
import "sync"
func NewPagination(data []interface{}, size int) *Pagination {
p := &Pagination{
data: data,
lock: new(sync.RWMutex),
}
p.SetPageSize(size)
return p
}
type Pagination struct {
data []interface{}
currentPage int
pageSize int
totalPage int
lock *sync.RWMutex
}
func (p *Pagination) GetNextPageData() []interface{} {
if !p.HasNext() {
return []interface{}{}
}
p.lock.Lock()
p.currentPage++
p.lock.Unlock()
return p.GetPageData(p.currentPage)
}
func (p *Pagination) GetPrevPageData() []interface{} {
if !p.HasPrev() {
return []interface{}{}
}
p.lock.Lock()
p.currentPage--
p.lock.Unlock()
return p.GetPageData(p.currentPage)
}
func (p *Pagination) GetPageData(pageIndex int) []interface{} {
p.lock.RLock()
defer p.lock.RUnlock()
var (
endIndex int
startIndex int
)
endIndex = p.pageSize * pageIndex
startIndex = endIndex - p.pageSize
if endIndex > len(p.data) {
endIndex = len(p.data)
}
return p.data[startIndex:endIndex]
}
func (p *Pagination) CurrentPage() int {
p.lock.RLock()
defer p.lock.RUnlock()
return p.currentPage
}
func (p *Pagination) TotalCount() int {
p.lock.RLock()
defer p.lock.RUnlock()
return len(p.data)
}
func (p *Pagination) TotalPage() int {
p.lock.RLock()
defer p.lock.RUnlock()
return p.totalPage
}
func (p *Pagination) SetPageSize(size int) {
if size <= 0 {
panic("Pagination size should be larger than zero")
}
p.lock.Lock()
defer p.lock.Unlock()
if p.pageSize == size {
return
}
p.pageSize = size
if len(p.data)%size == 0 {
p.totalPage = len(p.data) / size
} else {
p.totalPage = len(p.data)/size + 1
}
p.currentPage = 1
}
func (p *Pagination) PageSize() int {
p.lock.RLock()
defer p.lock.RUnlock()
return p.pageSize
}
func (p *Pagination) HasNext() bool {
p.lock.RLock()
defer p.lock.RUnlock()
return p.currentPage < p.totalPage
}
func (p *Pagination) HasPrev() bool {
p.lock.RLock()
defer p.lock.RUnlock()
return p.currentPage > 1
}