package com.mshc.util;

import java.util.Arrays;

import java.util.Collections;

import java.util.List;

/**

 * @author svs:

 * @version 创建时间：2016-12-16 下午02:28:23

 * 类说明

 */

public class ListPageUtil<T> {

    /**原集合*/

    private List<T> data;

    /** 上一页 */

    private int lastPage;

    /** 当前页 */

    private int nowPage;

    /** 下一页 */

    private int nextPage;

//

    /** 每页条数 */

    private int pageSize;

    /** 总页数 */

    private int totalPage;

    /** 总数据条数 */

    private int totalCount;

    public ListPageUtil(List<T> data,int nowPage,int pageSize) {

        if (data == null || data.isEmpty()) {

            throw new IllegalArgumentException("data must be not empty!");

        }

        this.data = data;

        this.pageSize = pageSize;

        /*this.totalPage = data.size()/pageSize;

        if(data.size()%pageSize!=0){

            this.totalPage++;

        }*/

        this.nowPage = nowPage;

        this.totalCount = data.size();

        this.totalPage = (totalCount + pageSize - 1) / pageSize;

        this.lastPage = nowPage-1>1? nowPage-1:1;

        this.nextPage = nowPage>=totalPage? totalPage: nowPage + 1;

    }

    /**

     * 得到分页后的数据

     *

     * @param pageNum 页码

     * @return 分页后结果

     */

    public List<T> getPagedList() {

        int fromIndex = (nowPage - 1) * pageSize;

        if (fromIndex >= data.size()) {

            return Collections.emptyList();//空数组

        }

        if(fromIndex<0){

            return Collections.emptyList();//空数组

        }

        int toIndex = nowPage * pageSize;

        if (toIndex >= data.size()) {

            toIndex = data.size();

        }

        return data.subList(fromIndex, toIndex);

    }

    public int getPageSize() {

        return pageSize;

    }

    public List<T> getData() {

        return data;

    }

    public int getLastPage() {

        return lastPage;

    }

    public int getNowPage() {

        return nowPage;

    }

    public int getNextPage() {

        return nextPage;

    }

    public int getTotalPage() {

        return totalPage;

    }

    public int getTotalCount() {

        return totalCount;

    }

   public static void main(String[] args) {
        Integer[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12};
        List<Integer> list = Arrays.asList(array);
 
       // ListPageUtil<Integer> pager = new ListPageUtil<Integer>(list, 10);
        ListPageUtil<Integer> listPageUtil = new ListPageUtil<Integer>(list,4, 5);
        List<Integer> pagedList = listPageUtil.getPagedList();
        System.out.println(pagedList);
    }

}