package util;
import java.util.List;
public class PageManager
{
private List allRecords = null;//collection储存同一类型的对象的集合
private int currentPage = 0;//当前页码
private int totalPage = 0;//总页数
private int recordPerPage = -1;//每页的对象数
private int totalCount=0;//总的对象数
//初始化
public PageManager(List allRecords, int recordPerPage)
{
if (allRecords == null || recordPerPage < 1) return;
this.allRecords = allRecords;
this.recordPerPage = recordPerPage;
this.totalCount=allRecords.size();
if (allRecords.size() % recordPerPage == 0)
this.totalPage = allRecords.size() / recordPerPage;
else
this.totalPage = allRecords.size() / recordPerPage + 1;
this.currentPage = 0;
}
//获取所有对象集合
public List getAllRecords()
{
return this.allRecords;
}
//获取当前页的的对象集合
public List getCurrentPage()
{
return getPage(currentPage);
}
//根据序号获取该对象所在的页的对象集合
public List getThePage(int recordno)
{
if (this.allRecords == null || this.allRecords.size() == 0)
{
this.currentPage = 0;
return null;
}
int pageNo=1;
if (recordno < 1) pageNo = 1;
else if (recordno > this.allRecords.size())
pageNo = this.totalPage;
else
{
pageNo=recordno/this.recordPerPage+1;
}
this.currentPage = pageNo;
int pageStart = (pageNo - 1) * this.recordPerPage;
int pageEnd = pageStart + this.recordPerPage - 1;
if (pageEnd > this.allRecords.size() - 1) pageEnd = this.allRecords.size() - 1;
List result =this.allRecords.subList(pageStart, pageEnd+1);
return result;
}
//根据页码获取改页的对象集合
public List getPage(int pageNo)
{
if (this.allRecords == null || this.allRecords.size() == 0)
{
this.currentPage = 0;
return null;
}
if (pageNo < 1) pageNo = 1;
if (pageNo > this.totalPage) pageNo = this.totalPage;
this.currentPage = pageNo;
int pageStart = (pageNo - 1) * this.recordPerPage;
int pageEnd = pageStart + this.recordPerPage - 1;
if (pageEnd > this.allRecords.size() - 1) pageEnd = this.allRecords.size() - 1;
List result =this.allRecords.subList(pageStart, pageEnd+1);
return result;
}
//获取下一页的对象集合
public List getNextPage()
{
return getPage(this.currentPage + 1);
}
//获取上一页的对象集合
public List getPreviousPage()
{
return getPage(this.currentPage - 1);
}
//获取第一页的对象集合
public List getFirstPage()
{
return getPage(1);
}
//获取最后一页的对象集合
public List getLastPage()
{
return getPage(this.totalPage);
}
//获取总页数
public int getTotalPage() {
return totalPage;
}
//获取当前页码
public int getCurrentPageCount()
{
return this.currentPage;
}
//获取对象总数
public int getTotalCount() {
return totalCount;
}
}
Let life be beautiful like summer flowers and death like autumn leaves.