dbmapping.java

EasyDBO是一个超轻量级对象-关系映射（Object/Relation Mapping

package com.easyjf.dbo;

import org.apache.log4j.*;

import java.util.*;

/**
 * 
 * <p>
 * Title:类及数据表的应射表
 * </p>
 * 
 * <p>
 * Description: 存放类及数据表的映射信息
 * </p>
 * 
 * <p>
 * 
 * @copyright: Copyright (c) 2006
 *             </p>
 * 
 * <p>
 * @company: EasyJF开源团队-EasyDBO项目组
 *           </p>
 * 
 * @author 大峡
 * @version 1.0
 */
public class DBMapping {
	private final static Logger logger = Logger.getLogger(DBMapping.class);

	private final static DBMapping dbmapping = new DBMapping();

	private final static Map map = new HashMap();

	// ~--- methods ------------------------------------------------------------
	/**
	 * 增加DBMapping
	 * 
	 * @param className
	 *            String 类
	 * @param table
	 *            DBTable 表
	 */
	public void add(Class clz, DBTable table) {
		map.put(clz, table);
	}

	/**
	 * 查找
	 * 
	 * @param tableName
	 *            String
	 * @return String
	 */
	public String findClass(String tableName) {
		String className = DBObject.class.toString();
		Iterator it = map.keySet().iterator();

		while (it.hasNext()) {
			String cls = (String) it.next();
			DBTable table = (DBTable) map.get(cls);

			if (table.getName().equals(tableName)) {
				className = cls;

				break;
			}
		}

		// System.out.println(className);
		return className;
	}

	/**
	 * 根据Class查找DBTable对象
	 * 
	 * @param cls
	 *            Class
	 * @return DBTable
	 */
	public DBTable findTable(Class cls) {
		if(DBObject.class==cls)return null;
		DBTable table = (DBTable) map.get(cls);
		if (table == null) {
			logger.info("找不到数据库映射" + cls.toString() + ",试着从子类中查找！");
			table = findTableByClass(cls);
			if (table == null) {
				logger.info("找不到数据库映射" + cls.toString() + ",试着从注解或IObject对象查找！");
				table = TableMappingParse.parseDomain(cls);
			}
			if (table != null)
				this.add(cls, table);
		}
		// System.out.println("字段数："+table.getPoperty("cid")+table.getFields().size());
		if (table == null) {
			logger.error("无法找到类" + cls.toString()
					+ "所映射的关系表，请通确保配置文件中具有该类的配置信息或者" + cls.toString()
					+ "实现IObject接口");
		}
		return table;
	}

	private DBTable findTableByClass(Class cls) {
		DBTable table = null;
		java.util.Iterator it = this.map.entrySet().iterator();
		while (it.hasNext()) {
			java.util.Map.Entry en = (java.util.Map.Entry) it.next();
			Class clz = (Class) en.getKey();
			if (clz.isAssignableFrom(cls))
				table = (DBTable) en.getValue();
		}
		return table;
	}

	/**
	 * 根据从MAP删除class
	 * 
	 * @param className
	 *            String
	 */
	public void remove(String className) {
		map.remove(className);
	}

	// ~--- get methods --------------------------------------------------------
	/**
	 * 获取当前接口
	 * 
	 * @return DBMapping
	 */
	public static DBMapping getInstance() {
		return dbmapping;
	}

	/**
	 * 
	 * @return Map
	 */
	public Map getMap() {
		return map;
	}
}