package com.mossle.core.page;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Locale;
/**
* 分页参数与分页结果.
*
* @author Lingo
*/
public class Page {
// ==========================================
// static fields...
/** 正序. */
public static final String ASC = "ASC";
/** 倒序. */
public static final String DESC = "DESC";
/** 默认每页显示10条数据. */
public static final int DEFAULT_PAGE_SIZE = 10;
// ==========================================
// fields...
/** 当前第几页，默认值为1，既第一页. */
private int pageNo = 1;
/** 每页最大记录数，默认值为10. */
private int pageSize = DEFAULT_PAGE_SIZE;
/** 排序字段名. */
private List<String> orderBys = new ArrayList<String>();
/** 使用正序还是倒序. */
private List<String> orders = new ArrayList<String>();
/** 查询结果. */
private Object result;
/** 总记录数，默认值为-1，表示totalCount不可用. */
private long totalCount = -1L;
/** 是否计算数据库中的记录总数. */
private boolean autoCount;
/** 当前页第一条记录的索引，默认值为0，既第一页第一条记录. */
private long start;
/** 总页数，默认值为-1，表示pageCount不可用. */
private long pageCount = -1;
// ==========================================
// constructor...
/** 构造方法. */
public Page() {
totalCount = 0;
result = new ArrayList();
}
/**
* 构造方法.
*
* @param result
* Object
* @param totalCount
* int
*/
public Page(Object result, int totalCount) {
this.result = result;
this.totalCount = totalCount;
}
/**
* 构造方法.
*
* @param pageNo
* int
* @param pageSize
* int
* @param orderBy
* String
* @param order
* String
*/
public Page(int pageNo, int pageSize, String orderBy, String order) {
this.pageNo = pageNo;
this.pageSize = pageSize;
this.setOrderBy(orderBy);
this.checkAndSetOrder(order);
this.calculateStart();
}
// ==========================================
// 工具方法
/**
* 是否为正序排序.
*
* @return boolean
*/
public boolean isAsc() {
return !DESC.equalsIgnoreCase(this.getOrder());
}
/**
* 取得倒转的排序方向.
*
* @return 如果dir=='ASC'就返回'DESC'，如果dir='DESC'就返回'ASC'
*/
public String getInverseOrder() {
if (DESC.equalsIgnoreCase(this.getOrder())) {
return ASC;
} else {
return DESC;
}
}
/**
* 页面显示最大记录数是否可用.
*
* @return pageSize > 0
*/
public boolean isPageSizeEnabled() {
return pageSize > 0;
}
/**
* 页面第一条记录的索引是否可用.
*
* @return start
*/
public boolean isStartEnabled() {
return start >= 0;
}
/**
* 排序是否可用.
*
* @return orderBy是否非空
*/
public boolean isOrderEnabled() {
return ((!orderBys.isEmpty()) && (!orders.isEmpty()));
}
/**
* 是否有前一页.
*
* @return boolean
*/
public boolean isPreviousEnabled() {
return pageNo > 1;
}
/**
* 是否有后一页.
*
* @return boolean
*/
public boolean isNextEnabled() {
return pageNo < pageCount;
}
/**
* 总页数是否可用.
*
* @return boolean
*/
public boolean isPageCountEnabled() {
return pageCount >= 0;
}
/** 计算本页第一条记录的索引. */
private void calculateStart() {
if ((pageNo < 1) || (pageSize < 1)) {
start = -1;
} else {
start = (pageNo - 1) * pageSize;
}
}
/** 计算最大页数. */
private void calculatePageCount() {
if ((totalCount < 0) || (pageSize < 1)) {
pageCount = -1;
} else {
pageCount = ((totalCount - 1) / pageSize) + 1;
}
}
// ==========================================
// getter and setter method...
/** @return pageNo. */
public int getPageNo() {
return pageNo;
}
/**
* @param pageNo
* int.
*/
public void setPageNo(int pageNo) {
this.pageNo = pageNo;
this.calculateStart();
}
/** @return pageSize. */
public int getPageSize() {
return pageSize;
}
/**
* @param pageSize
* int.
*/
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
this.calculateStart();
this.calculatePageCount();
}
/** @return orderBy. */
public String getOrderBy() {
if (!this.orderBys.isEmpty()) {
return this.orderBys.get(0);
}
return null;
}
/**
* @param orderBy
* String.
*/
public void setOrderBy(String orderBy) {
if ((orderBy == null) || (orderBy.trim().length() == 0)) {
throw new IllegalArgumentException("orderBy should be blank");
}
this.orderBys.clear();
this.orderBys.add(orderBy);
if (this.getOrders().size() != 1) {
this.setOrder(ASC);
}
}
/** @return order. */
public String getOrder() {
if (!this.orders.isEmpty()) {
return this.orders.get(0);
}
return ASC;
}
/**
* @param order
* String.
*/
public void setOrder(String order) {
this.checkAndSetOrder(order);
}
/** @return result. */
public Object getResult() {
return result;
}
/**
* @param result
* Object.
*/
public void setResult(Object result) {
this.result = result;
}
/** @return totalCount. */
public long getTotalCount() {
return totalCount;
}
/**
* @param totalCount
* int.
*/
public void setTotalCount(long totalCount) {
this.totalCount = totalCount;
this.calculatePageCount();
}
/** @return autoCount. */
public boolean isAutoCount() {
return autoCount;
}
/**
* @param autoCount
* boolean.
*/
public void setAutoCount(boolean autoCount) {
this.autoCount = autoCount;
}
/** @return start. */
public long getStart() {
return start;
}
/** @return pageCount. */
public long getPageCount() {
return pageCount;
}
/** @return result size. */
public int getResultSize() {
if (result instanceof Collection) {
return ((Collection) result).size();
} else {
return 0;
}
}
/**
* chck and set order.
*
* @param text
* String
*/
private void checkAndSetOrder(String text) {
if (ASC.equalsIgnoreCase(text) || DESC.equalsIgnoreCase(text)) {
text = text.toUpperCase(Locale.CHINA);
this.orders.clear();
this.orders.add(text);
} else {
throw new IllegalArgumentException(
"order should be 'DESC' or 'ASC'");
}
}
public void setDefaultOrder(String orderBy, String order) {
if (!this.isOrderEnabled()) {
this.setOrderBy(orderBy);
this.setOrder(order);
}
}
public void addOrder(String orderBy, String order) {
if (this.orderBys.size() != this.orders.size()) {
this.orderBys.clear();
this.orders.clear();
}
this.orderBys.add(orderBy);
if (ASC.equalsIgnoreCase(order) || DESC.equalsIgnoreCase(order)) {
order = order.toUpperCase(Locale.CHINA);
this.orders.add(order);
} else {
throw new IllegalArgumentException(
"order should be 'DESC' or 'ASC'");
}
}
public List<String> getOrderBys() {
return this.orderBys;
}
public void setOrderBys(List<String> orderBys) {
this.orderBys = orderBys;
}
public List<String> getOrders() {
return this.orders;
}
public void setOrders(List<String> orders) {
this.orders = orders;
}
}