cataloglisttag.java

来自「一个免费wap站」· Java 代码 · 共 160 行

package com.eline.wap.catalog.taglib;

import java.util.Collection;

import javax.servlet.http.HttpServletRequest;

import com.eline.wap.catalog.client.CatalogHelper;
import com.eline.wap.catalog.model.ItemCondition;
import com.eline.wap.common.model.Page;
import com.eline.wap.common.taglib.ListTag;
import com.eline.wap.common.util.StringUtils;

public class CatalogListTag extends ListTag {

	/**
	 * 
	 */
	private static final long serialVersionUID = 7563556938979707441L;

	private String prefix;
	private boolean hasNext = false;
	
	private int pageItems;			// 页面大小
	private int pageNum		= 0;	// 页号
	private int parentId	= -1;
	private boolean isActiveOnly	= false;

	private String searchKey	= null;
	private int type	= -1;	// 所有类型

	/**
	 * 缺省构造函数
	 *
	 */
	public CatalogListTag() {
		prefix = "CatalogList_";
	}

	/**
	 * 确定是否具有下页
	 * @return boolean-真时为有
	 */
	protected boolean needsNextForm() {
		return hasNext;
	}

	/**
	 * 设置列表标记前缀,用于避免与其它标记混
	 */
	protected void initParamPrefix() {
		super.paramPrefix = this.prefix;
	}

	/**
	 * 重载基类方法,在该方法中求出查询条件,查询数据库,并返回规定的查询结果
	 * @return Collection-符合条件的查询结果
	 * @throws Exception: 因为其为页面级调用,因此不返回异常 
	 */
	protected Collection findCollection() throws Exception {
		Collection coll = null;
		Page page = null;
		
		HttpServletRequest request = (HttpServletRequest) pageContext.getRequest();
		
		// 保证每次调用该列表页面时总显示第一页
		if(request.getParameter(prefix + "pageIndex") == null || request.getParameter(prefix + "pageIndex").equals("")
				|| request.getParameter(prefix + "pageIndex").equalsIgnoreCase("null"))
			pageIndex = 0;

		// 根据页面中查询条件形成查询值对象
		ItemCondition condition = fillQueryCondition();
		
		// 查询结果
		CatalogHelper ch = new CatalogHelper();
		int start = pageIndex * pageSize;
		page = ch.searchItems(condition, start, pageSize);
		coll = page.getItems();
		
		// 为基类相应属性赋值,写共几条记录,共几页第几页用
		totalRecords = page.getTotalRecords();	// 共有多少条记录
		totalPages = (totalRecords + pageSize - 1) / pageSize;	// 共有多少页
		
		// 是否有下页
		hasNext = ((pageIndex + 1) < totalRecords) ? true : false;

		return coll;
	}

    /**
     * 根据JSP页面所传来的参数形成查询条件值对象
     * @return ItemCondition 目录查询条件值对象
     */
	private ItemCondition fillQueryCondition() {
		ItemCondition condition = new ItemCondition();
		boolean hasCondition = false;
		
		if (parentId >= 0) {
			condition.setParentId(parentId);
			hasCondition = true;
		}
		if (isActiveOnly == false) {
			condition.setActiveOnly(false);
			hasCondition = true;
		}
		// 目录搜索
		if (searchKey != null && searchKey.length() > 0) {
			condition.setSearchKeywords(searchKey);
			hasCondition = true;
		}
		if (type != -1) {
			condition.setType(type);
			hasCondition = true;
		}
		
		return hasCondition ? condition : null;
	}

	/**
	 * 标签库参数: 由jsp页面进行赋值,指定父目录
	 * @param parentId : int 父目录ID号
	 */
	public void setParentId(int parentId) {
		this.parentId = parentId;
	}

    /**
     * 标签库参数: 由JSP页面设置每页记录数,初始化基类对应属性pageSize
     * @param pageNum: int-每页记录数
     */
	public void setPageItems(String pageItems) {
		this.pageItems = StringUtils.getInt(pageItems, 10);
		super.pageSize = this.pageItems;
	}

    /**
     * 标签库参数: 由JSP页面设置页号,初始化基类对应属性pageIndex
     * @param pageNum: String-页号
     */
	public void setPageNum(String pageNum) {
		this.pageNum = StringUtils.getInt(pageNum, 0);
		super.pageIndex = this.pageNum;
	}

	/**
	 * 标签库参数: 由JSP页面设置显示级别
	 * @param activeOnly: boolean 显示活跃的元素/非活跃元素
	 */
	public void setActiveOnly(boolean isActiveOnly) {
		this.isActiveOnly = isActiveOnly;
	}
	
	public void setSearchKey(String searchKey) {
		this.searchKey = searchKey;
	}

	public void setType(int type) {
		this.type = type;
	}
}