errormessages.java

我在加拿大学习的一个比较复杂的在线银行程序.

package com.ebusiness.ebank.exception;

/**
 * <p>Title: </p>
 * <p>Description: This class defines Message keys and provides a static method
 *                  to get langauge-based message</p>
 * <p>Copyright: Copyright (c) 2005</p>
 * <p>Company: eBusiness Inc., All right reserved</p>
 * @author unascribed
 * @version 1.0
 */

import java.util.Map;
import java.util.HashMap;
import java.util.Set;
import java.util.HashSet;
import java.util.Properties;
import java.util.Enumeration;
import java.util.Locale;
import java.io.InputStream;

import org.apache.log4j.Logger;
import org.apache.log4j.MDC;

public class ErrorMessages
{
    //Business Error Message key Definition
        //Please note: The actual message descriptions are defined in errorMessage properties files

    //common message keys
    public final static String RECORD_CHANGED =     "common.RecordChanged";
    public final static String RECORD_DELETED =     "common.RecordDeleted";
    public final static String NO_RECORD_FOUND =    "common.NoRecordFound";
    public final static String INVALID_FLAG =       "common.InvalidFlag";
    public final static String INVALID_LANGUAGE =   "common.InvalidLanguage";
    public final static String NOT_ENOUGH_DATA =    "common.NotEnoughData";

    public final static String INVALID_EXPIRY_DATE= "common.InvalidExpiryDate";

    //common message keys specific for Security
    public final static String NO_SAVE_AUTHORIZED =         "security.NoSaveAuthorized";
    public final static String NO_UPDATE_AUTHORIZED =       "security.NoUpdateAuthorized";
    public final static String NO_DELETE_AUTHORIZED =       "security.NoDeleteAuthorized";
    public final static String NO_VIEW_AUTHORIZED =         "security.NoViewAuthorized";

    public final static String NO_TRANSFER_AUTHORIZED =     "security.NoTransferAuthorized";
    public final static String NO_DEPOSIT_AUTHORIZED =       "security.NoDepositAuthorized";
    public final static String NO_WITHDRAWAL_AUTHORIZED =    "security.NoWithdrawalAuthorized";
    public final static String NO_PAYBILL_AUTHORIZED =       "security.NoPayBillAuthorized";

    //ClientCard related message keys
    public final static String WRONG_PASSWORD       =   "clientcard.WrongPassword";
    public final static String MISSING_NEWPASSWORD  =   "clientcard.MissingNewPassword";
    public final static String PASSWORD_NOT_MATCH   =   "clientcard.PasswordNotMatch";
    public final static String PASSWORD_DUPLICATE   =   "clientcard.PasswordDuplicate";
    public final static String NO_CLIENTCARD_FOUND   =  "clientcard.NoClientCardFound";

    //Cardholder related message keys
    public final static String INVALID_SIN          = "cardholder.InvalidSIN";
    public final static String NO_CARDHOLDER_FOUND  = "cardholder.NoCardholderFound";

    //Address related message keys
    public final static String CANNOT_DELETE_ADDRESS =      "address.CannotDeleteAddress";
    public final static String INVALID_ADDRESS_TYPE =       "address.InvalidAddressType";
    public final static String COUNTRY_NOT_EXIST =          "address.CountryNotExist";
    public final static String STATE_NOT_EXIST =            "address.StateNotExist";

    public final static String INCORRECT_POSTAL_CODE_FORMAT = "address.IncorrectPostalCodeFormat";

    //Account related message keys
    public final static String INVALID_ACCOUNT = "account.InvalidAccount";
    public final static String EXCEED_LIMIT = "account.ExceedLimit";
    public final static String WITHDRAWAL_RESTRICTED = "account.WithdrawalRestricted";
    public final static String CANNOT_TRANSFER_TO_ITSELF = "account.CannotTransferToItself";
    public final static String NO_ACCOUNT_FOUND = "account.NoAccountFound";

    //Below Defines System Error Messages
    public final static String FAIL_TO_CREATE_DATABASE_CONNECTION = "Fail to establish database connection";
    public final static String FAIL_TO_CLOSE_DATABASE_STATEMENT = "Fail to close database statement";
    public final static String FAIL_TO_CLOSE_DATABASE_CONNECTION = "Fail to close database connection";
    public final static String FAIL_TO_ROLL_BACK = "Fail to roll back database changes";
    public final static String OTHER_DATABASE_ERROR = "Database Error";

    public final static String FAIL_TO_INSTANTIATE_SERVICELOCATOR = "Fail to instantiate ServiceLocator";
    public final static String FAIL_TO_LOOKUP_LOCALHOME = "Fail to lookup LocalHome";
    public final static String FAIL_TO_LOOKUP_REMOTEHOME = "Fail to lookup RemoteHome";
    public final static String FAIL_TO_LOOKUP_DATASOURCE = "Fail to lookup DataSource";

    public final static String CLASS_CAST = "Class Cast Exception";

    public final static String EJB_CREATE_ERROR = "Fail to Create EJB";
    public final static String EJB_LOCALEXCEPTION_ERROR = "EJB LocalException error";
    public final static String EJB_REMOTEEXCEPTION_ERROR = "EJB RemoteException error";
    public final static String EJB_FINDEREXCEPTION_ERROR = "EJB FinderException error";

    public final static String NO_VALUE = "No current value available";

    //Hold message key and message description (value)
    private static Map messages;
    private static Map messagesByKey;

    //Hold all language codes which are available for the application
    private static String languages[];

    private static Logger log = Logger.getLogger("com.ebusiness.ebank.exception.ErrorMessages");

    //load error message properties and store them to HashMap
    static
    {
        messages = new HashMap();
        messagesByKey = new HashMap();
        initMessages();
    }

    //return message descriptions in all languages for the specified message key
    public static Map getMessages(String key)
    {
        Map map = (Map)messagesByKey.get(key);
        if (map != null)
            return map;
        map = new HashMap();
        for (int i = 0; i < languages.length; i++)
        {
            map.put(languages[i], ((Map)messages.get(languages[i])).get(key));
        }
        messagesByKey.put(key, map); //put the messages to messagesByKey for future access
        return map;
    }

    /**
     * <p>Description: Read and load all error messages from properties files(one file for each language)
     *      to HashMap for reuse.
     *
     *      The English properties file will be errorMessages.properties. All other language
     *      properties files format is errorMessages_ concatenating with ISO languageCode
     *      and concatenating with .properties. For example:
     *          errorMessages_fr.properties is French errorMessages properties file
     * </p>
     *
     */
    private static void initMessages()
    {
        Class clazz = null;
        try
        {
            clazz = Class.forName("com.ebusiness.ebank.exception.ErrorMessages");
        }
        catch (Exception e)
        {
            log.error("Cannot find ErrorMessages class: ");
        }
        InputStream inStream;
        String[] lCodes = Locale.getISOLanguages();
        Properties prop;
        Enumeration props;
        Map mesgsWithSameLang;
        String fileName;
        String key;

        for (int i = 0; i < lCodes.length; i++)
        {
            if ("en".equals(lCodes[i]))
                fileName = "errorMessage.properties";
            else
                fileName = "errorMessage_" + lCodes[i] + ".properties";
            try
            {
                inStream = clazz.getResourceAsStream(fileName);
                if (inStream != null)
                {
                    prop = new Properties();
                    prop.load(inStream);

                    props = prop.propertyNames();
                    mesgsWithSameLang = new HashMap();
                    while(props.hasMoreElements())
                    {
                        key = (String)props.nextElement();
                        mesgsWithSameLang.put(key, prop.getProperty(key));
                    }
                    //If messages in this languages is not empty, then put them to messages
                    if (!mesgsWithSameLang.isEmpty())
                        messages.put(lCodes[i], mesgsWithSameLang);
                }
            }
            catch (Exception e)
            {
                log.error("Cannot load file: " + fileName);
            }
        }
        languages = (String[])messages.keySet().toArray(new String[messages.size()]);
    }
}