difficultyenum.java

老外的在线考试

/*
 * SchoolEJB - CyberDemia's library of EJBs for educational related services.
 * Copyright (C) 2003 CyberDemia Research and Services
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA  02111-1307, USA.
 *
 * See the COPYING file located in the top-level-directory of
 * the archive of this library for complete text of license.
 */
package com.cyberdemia.school;

import com.cyberdemia.generic.AbstractEnum;
import java.util.*;

/**
 * 
 * DifficultyEnum represents an enumerated type to 
 * indicate the difficulty level of a question.
 * 
 * @author Alexander Yap
 */
public final class DifficultyEnum extends AbstractEnum
{
	// Name strings. Used for display in GUIs, output, etc
	private static final String TRIVIAL_NAME = "Trivial";
	private static final String EASY_NAME = "Easy";
	private static final String INTERMEDIATE_NAME = "Intermediate";
	private static final String HARD_NAME = "Hard";
	private static final String EXTREME_NAME = "Extreme";

	// Enum strings. This is the same as the programatic name.
	private static final String TRIVIAL_STR = "TRIVIAL";
	private static final String EASY_STR = "EASY";
	private static final String INTERMEDIATE_STR = "INTERMEDIATE";
	private static final String HARD_STR = "HARD";
	private static final String EXTREME_STR = "EXTREME";

	// Enums
	public static final DifficultyEnum TRIVIAL = new DifficultyEnum(new Integer(1),TRIVIAL_STR,TRIVIAL_NAME);
	public static final DifficultyEnum EASY = new DifficultyEnum(new Integer(2),EASY_STR,EASY_NAME);
	public static final DifficultyEnum INTERMEDIATE = new DifficultyEnum(new Integer(3),INTERMEDIATE_STR,INTERMEDIATE_NAME);
	public static final DifficultyEnum HARD = new DifficultyEnum(new Integer(4),HARD_STR,HARD_NAME);
	public static final DifficultyEnum EXTREME = new DifficultyEnum(new Integer(5),EXTREME_STR,EXTREME_NAME);

	// Map of enum string to Integer.
	private static Map s_strToEnumMap = new HashMap();
	// Map of Integer code to AbstractEnum instance.
	private static Map s_codeToEnumMap = new HashMap();

	static
	{
		s_strToEnumMap.put(TRIVIAL_STR,TRIVIAL);
		s_codeToEnumMap.put(TRIVIAL.getCode(),TRIVIAL);
		s_strToEnumMap.put(EASY_STR,EASY);
		s_codeToEnumMap.put(EASY.getCode(),EASY);
		s_strToEnumMap.put(INTERMEDIATE_STR,INTERMEDIATE);
		s_codeToEnumMap.put(INTERMEDIATE.getCode(),INTERMEDIATE);
		s_strToEnumMap.put(HARD_STR,HARD);
		s_codeToEnumMap.put(HARD.getCode(),HARD);
		s_strToEnumMap.put(EXTREME_STR,EXTREME);
		s_codeToEnumMap.put(EXTREME.getCode(),EXTREME);
	}

	/**
	* Returns enumerate from the string representation of the enumerate.
	* @param enumStr  String to search for.
	* @return Enumerate specified by the string if it exists, otherwise null.
	*/
	public static DifficultyEnum getEnumFromString(String enumStr)
	{
		if (!s_strToEnumMap.containsKey(enumStr))
			return null;
		return (DifficultyEnum)s_strToEnumMap.get(enumStr);
	}

	/**
	* Returns enumerate that matches specified code.
	* @param code  Code to search for.
	* @return Enumerate specified by the code if it exists, otherwise null.
	*/
	public static DifficultyEnum getEnumFromCode(Integer code)
	{
		if (!s_codeToEnumMap.containsKey(code))
			return null;
		return (DifficultyEnum)s_codeToEnumMap.get(code);
	}

	/**
	* Returns array of all defined DifficultyEnum objects, sorted by their codes in ascending order.
	* This method creates a new array.
	* @return Array of all defined enumerates.
	*/
	public static DifficultyEnum[] getEnums()
	{
		LinkedList enumList = new LinkedList( s_codeToEnumMap.values() );
		Collections.sort( enumList );
		DifficultyEnum[] enumArray = new DifficultyEnum[enumList.size()];
		return (DifficultyEnum[])enumList.toArray(enumArray);
	}

	// ctor protected to prevent user instantiation

	protected DifficultyEnum(Integer code, String str, String name)
	{
		super(code, str, name);
	}

	protected DifficultyEnum()  { super(); }  // Not used.
}