com.github.dennisit.vplus.data.page.Pagination Maven / Gradle / Ivy

Go to download
/*--------------------------------------------------------------------------
 *  Copyright (c) 2010-2020, Elon.su All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * Neither the name of the elon developer nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * Author: Elon.su, you can also mail [email protected]
 *--------------------------------------------------------------------------
*/
package com.github.dennisit.vplus.data.page;

import com.alibaba.fastjson.JSON;
import com.google.common.collect.Lists;
import lombok.Data;

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

/**
 * Created by Elon.su on 17/9/30.
 */
@Data
public class Pagination {

    /**
     * 页码数
     */
    private int page;

    /**
     * 每页大小
     */
    private int size;

    /**
     * 总共页码数
     */
    private int pageTotal;

    /**
     * 库表行数
     */
    private long rowTotal;

    /**
     * 当前页数据集
     */
    private List items = Lists.newArrayList();

    /**
     * 默认每页数据大小
     */
    public static final Integer DEFAULT_PAGE_SIZE = 20;

    /**
     * 查询参数(用于透传)
     */
    private Map query;


    public static Pagination empty(){
        return new Pagination<>();
    }

    /**
     * 无参构造
     */
    public Pagination() {
        this(new ArrayList(), 0, 1);
    }

    public Pagination(List list, long rowTotal, int page) {
        setPage(list, rowTotal, page, DEFAULT_PAGE_SIZE);
    }

    public Pagination(List list, long rowTotal, int page, int size) {
        setPage(list, rowTotal, page, size);
    }


    private void setPage(List list, long rowTotal, int page, int size) {
        page = Math.abs(page);
        size = Math.abs(size);
        int pageCount = (int)(rowTotal - 1) / size + 1;
        if(page >= pageCount){
            page = pageCount;
        }
        this.setItems(list);
        this.setPageTotal(pageCount);
        this.setPage(page);
        this.setSize(size);
        this.setRowTotal(rowTotal);
    }

    public long getPageTotal() {
        if (this.getSize() > 0) {
            return ((this.getRowTotal() - 1) / this.getSize() + 1);
        }
        return 0;
    }

    public boolean isFirstPage(){
        return 1 == this.getPage();
    }

    public boolean isLastPage(){
        return this.getPage() == this.getPageTotal();
    }

    public boolean isNextPage() {
        return ((this.getPageTotal() > 1) && (this.getPage() < this.getPageTotal()));
    }

    public boolean isPrePage() {
        return ((this.getPageTotal() > 1) && (this.getPage() > 1));
    }

    @Override
    public String toString(){
        return JSON.toJSONString(this);
    }
}