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本文次要钻研一下gost的Pager

Pager

gost/hash/page/pager.go

// Pager is the abstraction for pagination usage.type Pager interface {    // GetOffset will return the offset    GetOffset() int    // GetPageSize will return the page size    GetPageSize() int    // GetTotalPages will return the number of total pages    GetTotalPages() int    // GetData will return the data    GetData() []interface{}    // GetDataSize will return the size of data.    // Usually it's len(GetData())    GetDataSize() int    // HasNext will return whether has next page    HasNext() bool    // HasData will return whether this page has data.    HasData() bool}
Pager接口定义了GetOffset、GetPageSize、GetTotalPages、GetData、GetDataSize、HasNext、HasData办法

Page

gost/hash/page/page.go

// Page is the default implementation of Pager interfacetype Page struct {    requestOffset int    pageSize      int    totalSize     int    data          []interface{}    totalPages    int    hasNext       bool}// GetOffSet will return the offsetfunc (d *Page) GetOffset() int {    return d.requestOffset}// GetPageSize will return the page sizefunc (d *Page) GetPageSize() int {    return d.pageSize}// GetTotalPages will return the number of total pagesfunc (d *Page) GetTotalPages() int {    return d.totalPages}// GetData will return the datafunc (d *Page) GetData() []interface{} {    return d.data}// GetDataSize will return the size of data.// it's len(GetData())func (d *Page) GetDataSize() int {    return len(d.GetData())}// HasNext will return whether has next pagefunc (d *Page) HasNext() bool {    return d.hasNext}// HasData will return whether this page has data.func (d *Page) HasData() bool {    return d.GetDataSize() > 0}
Page定义了requestOffset、pageSize、totalSize、data、totalPages、hasNext属性；它实现了Pager接口，其GetDataSize办法返回的是len(d.GetData())；其HasData办法应用d.GetDataSize() > 0来判断

NewPage

gost/hash/page/page.go

// NewPage will create an instancefunc NewPage(requestOffset int, pageSize int,    data []interface{}, totalSize int) *Page {    remain := totalSize % pageSize    totalPages := totalSize / pageSize    if remain > 0 {        totalPages++    }    hasNext := totalSize-requestOffset-pageSize > 0    return &Page{        requestOffset: requestOffset,        pageSize:      pageSize,        data:          data,        totalSize:     totalSize,        totalPages:    totalPages,        hasNext:       hasNext,    }}
NewPage办法依据requestOffset、pageSize、data、totalSize来结构Page；它会计算totalPages、hasNext

实例

gost/hash/page/page_test.go

func TestNewDefaultPage(t *testing.T) {    data := make([]interface{}, 10)    page := NewPage(121, 10, data, 499)    assert.Equal(t, 10, page.GetDataSize())    assert.Equal(t, 121, page.GetOffset())    assert.Equal(t, 10, page.GetPageSize())    assert.Equal(t, 50, page.GetTotalPages())    assert.Equal(t, data, page.GetData())    assert.True(t, page.HasNext())    assert.True(t, page.HasData())    page = NewPage(492, 10, data, 499)    assert.False(t, page.HasNext())}

小结

gost的Pager接口定义了GetOffset、GetPageSize、GetTotalPages、GetData、GetDataSize、HasNext、HasData办法；Page定义了requestOffset、pageSize、totalSize、data、totalPages、hasNext属性；它实现了Pager接口。

doc

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