coursetransactionmanager.java

一个在线学习系统的服务端SERVLET程序

package eols.logic.course;

import java.util.Map;
import eols.bean.course.*;
import eols.logic.base.ITransaction;
import eols.storage.base.IStorage;
import eols.storage.course.CourseStorageManager;

public class CourseTransactionManager implements ITransaction {

	/* The storage manager used in this transaction manager */
	private IStorage iSQL = new CourseStorageManager();

	/**
	 * Return the storage manager used by this
	 * transaction manager.
	 *
	 * @return The used storage manager
	 */
	public IStorage getStorageManager(){
		return iSQL;
	}

	/**
	 * Process the specified transaction. All necessary parameters are
	 * wrapped in a map which is provided by specific caller.
	 *
	 * <p>
	 * A runtime exception may be thrown out, according to specific
	 * transactions.
	 * </p>
	 *
	 * <p>
	 * In this subsystem, the parameters contains the type of the transaction,
	 * the necessary parameters of the transaction.
	 * </p>
	 *
	 * @param parameters Parameters to pass
	 * @return The handling result object
	 */
	public Object process(Map parameters){
		// Get the transaction type
		String type = (String)parameters.get("type");
		if (type == null) {
			throw new RuntimeException("The transaction type shall be specified.");
		}
		if (type.equals("CREATENEWCATEGORY")) { /** Create a new category */
			Category newC = (Category)parameters.get("category");
			if (iSQL.addRecord(newC)) {
				return new Boolean(true);
			}
			return new Boolean(false);
		}
		if (type.equals("CREATENEWCOURSE")) { /** Create a new course */
			Course newC = (Course)parameters.get("course");
			if (iSQL.addRecord(newC)) {
				return new Boolean(true);
			}
			return new Boolean(false);
		}
		if (type.equals("CREATENEWCHAPTER")) { /** Create a new chapter */
			Chapter newC = (Chapter)parameters.get("chapter");
			if (iSQL.addRecord(newC)) {
				return new Boolean(true);
			}
			return new Boolean(false);
		}
		if (type.equals("CREATENEWCONTENT")) { /** Create a new content */
			Content newC = (Content)parameters.get("content");
			if (iSQL.addRecord(newC)) {
				return new Boolean(true);
			}
			return new Boolean(false);
		}
		if (type.equals("CREATENEWWORD")) { /** Create a new word */
			Word newC = (Word)parameters.get("word");
			if (iSQL.addRecord(newC)) {
				return new Boolean(true);
			}
			return new Boolean(false);
		}
		if (type.equals("UPDATECATEGORY")) { /** Update the existing category */
			Category newC = (Category)parameters.get("category");
			if (iSQL.updateRecord(null, newC)) {
				return new Boolean(true);
			}
			return new Boolean(false);
		}
		if (type.equals("UPDATECOURSE")) { /** Update the existing course */
			Course newC = (Course)parameters.get("course");
			if (iSQL.updateRecord(null, newC)) {
				return new Boolean(true);
			}
			return new Boolean(false);
		}
		if (type.equals("UPDATECHAPTER")) { /** Update the existing chapter */
			Chapter newC = (Chapter)parameters.get("chapter");
			if (iSQL.updateRecord(null, newC)) {
				return new Boolean(true);
			}
			return new Boolean(false);
		}
		if (type.equals("UPDATECONTENT")) { /** Update the existing content */
			Content newC = (Content)parameters.get("content");
			if (iSQL.updateRecord(null, newC)) {
				return new Boolean(true);
			}
			return new Boolean(false);
		}
		if (type.equals("UPDATEWORD")) { /** Update the existing word */
			Word newC = (Word)parameters.get("word");
			if (iSQL.updateRecord(null, newC)) {
				return new Boolean(true);
			}
			return new Boolean(false);
		}
		return null;
	}

}