com.simple.orm.domain.PageImpl Maven / Gradle / Ivy

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package com.simple.orm.domain;

import java.util.ArrayList;
import java.util.List;

/**
 * 分页内容实现类
 * @param  M 数据的实体对象
 */
public class PageImpl implements Page {
    private final Pageable pageable;
    private final long total;
    private List contents = new ArrayList();
    private static final int MAX_DISPLAY_PAGE_NUM = 5;  //一页最大显示页码数

    //总页数
    private int pages=0;
    
    /**
     * 分页构造
     * @param contents 页面中的内容
     * @param pageable 页码分页构造器
     * @param total    总条数
     */
    public PageImpl(List contents, Pageable pageable, long total) {
        this.pageable = pageable;
        this.total = total;
        this.contents = contents;
        this.pages=(int) Math.ceil((double) total / (double) pageable.getPageSize());
    }

    /**
     * 获取下一页页码
     * @return 返回下一页页码
     */
    public Integer getNextPageNum() {
        return getCurrentPageNum() < getPages() ? getCurrentPageNum() + 1 : -1;
    }

    /**
     * 上一页页码
     * @return 上一页页码
     */
    public Integer getPrevPageNum() {
        return getCurrentPageNum() > 1 ? getCurrentPageNum() - 1 : -1;
    }

    /**
     * 获取当前的页码
     * @return 返回当前的页码数
     */
    public Integer getCurrentPageNum() {
        return pageable.getCurrentPageNum();
    }

    /**
     * 获取页码列表
     * @return 返回页码列表
     */
	public int[] getPageNums() {
		int start;
		int end;
		int mid = (int) Math.ceil((double) MAX_DISPLAY_PAGE_NUM / 2);
		if (getCurrentPageNum() <= mid) {
			start = 1;
			end = getPages() > MAX_DISPLAY_PAGE_NUM ? MAX_DISPLAY_PAGE_NUM : getPages();
		} else if (getCurrentPageNum() >= getPages() - mid) {
			start = getPages() - MAX_DISPLAY_PAGE_NUM + 1;
			end = getPages();
		} else {
			start = getCurrentPageNum() - 2;
			int temp = getCurrentPageNum() + 2;
			end = temp > getPages() ? getPages() : temp;
		}
		int[] pageNums = new int[end - start + 1];
		for (int i = 0; start <= end; start++, i++) {
			pageNums[i] = start;
		}
		return pageNums;
	}

    /**
     * 获取总条数
     * @return 返回总条数
     */
    public long getTotal() {
        return this.total;
    }

    /**
     * 获取页码总数
     * @return 返回总页数
     */
    public int getPages() {
        return this.pages;
    }

    /**
     * 返回页码里面的元素
     *
     * @return 返回页码里面的元素
     */
    public List getContents() {
        return this.contents;
    }

}