/*
* 文件名称: PageInfo.java
* 版权信息: Copyright 2001-2011 ZheJiang chunchen Data System Co., LTD. All right reserved.
* ----------------------------------------------------------------------------------------------
* 修改历史:
* ----------------------------------------------------------------------------------------------
* 修改原因: 新增
* 修改人员: LuoJingtian
* 修改日期: 2011-12-14
* 修改内容:
*/
package com.mfh.comn.bean;
/**
* 分页信息,注意第一页用1表示，不是0，这与服务器端一致。
* @author <a href="mailto:luojt@zjcds.com">LuoJingtian</a> created on 2011-12-14
*/
public class PageInfo {
public static final int FIRST_PAGE_NO = 1;
public static final int DEFAULT_PAGE_SIZE = 20;
public final static int TOTALCOUNT_NOTINIT = -1;
public final static int PAGENO_NOTINIT = 0;
public final static int PAGENO_LASTNO = 999999999;//代表最后一页，具体页数需要待定。
private boolean fromLast = false;
/** 当前页号，1代表第一页；0代表未初始化 */
private int pageNo = PAGENO_NOTINIT;
/** 每页记录条数 */
private int pageSize = DEFAULT_PAGE_SIZE;
/** 总页数*/
private int totalPage = 0;
/** 总记录数 */
private int totalCount = TOTALCOUNT_NOTINIT;
/** 默认构造函数 */
public PageInfo() {
pageSize = DEFAULT_PAGE_SIZE;
}
/**
* 翻页次序，是否从后往前
* @return
*/
public boolean isFromLast() {
return fromLast;
}
/**
* 构造函数
* @param pageSize
*/
public PageInfo(int pageSize) {
this.pageSize = pageSize;
}
/** 构造函数 */
public PageInfo(int pageNo, int pageSize) {
this.pageNo = pageNo;
if (pageNo == PAGENO_LASTNO)
fromLast = true;
else
fromLast = false;
this.pageSize = pageSize;
}
/**
* 构造函数
* @param fromLast 是否反向
* @param pageSize 页数
*/
public PageInfo(boolean fromLast, int pageSize) {
this.pageSize = pageSize;
this.fromLast = fromLast;
if (fromLast)
this.pageNo = PAGENO_LASTNO;
else
this.pageNo = PAGENO_NOTINIT;
}
/**
* 设置总数
* @param totalCount
*/
public void setTotalCount(int totalCount) {
this.totalCount = totalCount;
reCalcTotalCount(totalCount, pageSize);
}
/**
* 重置
* @author zhangyz created on 2013-4-11
*/
public void reset() {
totalPage = 0;
this.totalCount = TOTALCOUNT_NOTINIT;
if (fromLast)
this.pageNo = PAGENO_LASTNO;
else
this.pageNo = PAGENO_NOTINIT;
}
/**
* @param totalCount
* @author huangwb created on 2012-2-23
* @since
*/
private void reCalcTotalCount(int totalCount, int pageSize) {
if (pageSize != 0) {
totalPage = totalCount / pageSize;
if (totalCount % pageSize > 0) {
totalPage ++;
}
//如果指示从后向开始且未初始化，则直接跳到开始处（即最后一页）
if (pageNo == PAGENO_LASTNO)
this.moveToFirst();
else if (pageNo == PAGENO_LASTNO - 1) {//可能已经moveNext过一次了。
this.moveToFirst();
this.moveToNext();//补充move一下
}
}
}
public int getPageSize() {
return pageSize;
}
/**
* @return
* @author zhangyz created on 2013-4-11
*/
public int getPageNo() {
return pageNo;
}
/**
* 设置页号，1代表第一页。
* 建议用prePageNo和nextPageNo代替
* @param pageNo
* @author zhangyz created on 2013-4-11
*/
public void setPageNo(int pageNo) {
if (pageNo > 0) {
this.pageNo = pageNo;
if (pageNo == PAGENO_LASTNO)
fromLast = true;
else
fromLast = false;
}
}
public int getPageIndex() {
return pageNo - 1;
}
/**
* 是否还未初始化过，即没有读过总记录数
* @return
* @author zhangyz created on 2013-4-11
*/
public boolean isNotInit() {
if (this.totalCount == TOTALCOUNT_NOTINIT)
return true;
else
return false;
}
/**
* 是否还有下一页
* @return
* @author zhangyz created on 2013-4-11
*/
public boolean hasNextPage() {
if (fromLast) {
if (pageNo >= FIRST_PAGE_NO || isNotInit())
return true;
else
return false;
}
else {
if (pageNo < totalPage || isNotInit())
return true;
else
return false;
}
}
/**
* 翻到下一页
* @return 返回页号
* @author zhangyz created on 2013-4-11
*/
public int moveToNext() {
if (fromLast) {
if (hasNextPage())
pageNo--;
return pageNo - 1;
}
else {
if (hasNextPage())
pageNo++;
else
throw new RuntimeException("已经是最后一页!");
return pageNo - 1;
}
}
/**
* 翻到最后一页
* @return 返回上页
* @author zhangyz created on 2013-4-15
*/
public void moveToLast () {
if (fromLast)
pageNo = FIRST_PAGE_NO;
else
pageNo = this.totalPage;
}
/**
* 移到第一页
*
* @author zhangyz created on 2013-4-15
*/
public void moveToFirst() {
if (fromLast)
pageNo = this.totalPage;
else
pageNo = FIRST_PAGE_NO;
}
/**
* 是否还有上一页
* @return
* @author zhangyz created on 2013-4-13
*/
public boolean hasPrevPage() {
if (fromLast) {
if (pageNo < this.totalPage)
return true;
else
return false;
}
else {
if (pageNo <= FIRST_PAGE_NO)
return false;
else
return true;
}
}
/**
* 移到上一页
* @return 返回页号
* @author zhangyz created on 2013-4-11
*/
public int moveToPrev() {
if (fromLast) {
pageNo++;
return pageNo - 1;
}
else {
pageNo--;
return pageNo - 1;
}
}
public void setPageSize(int pageSize) {
if (pageSize > 0) {
this.pageSize = pageSize;
reCalcTotalCount(totalCount, pageSize);
}
}
public int getTotalCount() {
return totalCount;
}
/**
* 获取已经读取的个数。不是很精确。因为最后一页可能没有读满。
* @return 0:代表还未读取；>0,代表读取至的位置
* @author zhangyz created on 2013-5-7
*/
public int getHavedCount() {
int haveCount;
if (fromLast)
haveCount = (totalPage - pageNo) * pageSize;
else
haveCount = (pageNo) * pageSize;
if (haveCount < 0)
haveCount = 0;
if (haveCount > totalCount)
haveCount = totalCount;
return haveCount;
}
/**
* 获取上一次读取结束的位置，用于分页
* @return 0:代表还未读取；>0,代表读取至的位置
* @author zhangyz created on 2013-5-7
*/
public int getStartCount() {
int haveCount;
if (fromLast)
haveCount = pageNo * pageSize;
else
haveCount = (pageNo -1) * pageSize;
if (haveCount < 0)
haveCount = 0;
return haveCount;
}
public void setTotalPage(int totalPage) {
this.totalPage = totalPage;
}
public int getTotalPage() {
return totalPage;
}
/**
* 直接设置成一页
* @param totalCount
* @author zhangyz created on 2013-6-6
*/
public void setToOnePage(int totalCount) {
if (isNotInit()) {//一次性查出，无须分页。
setPageSize(totalCount + 1);
setTotalCount(totalCount);
}
}
}