usererror.java

著名的开源仿真软件yale

/*
 *  YALE - Yet Another Learning Environment
 *  Copyright (C) 2002, 2003
 *      Simon Fischer, Ralf Klinkenberg, Ingo Mierswa, 
 *          Katharina Morik, Oliver Ritthoff
 *      Artificial Intelligence Unit
 *      Computer Science Department
 *      University of Dortmund
 *      44221 Dortmund,  Germany
 *  email: [e-mail]
 *  web:   http://yale.cs.uni-dortmund.de/
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License as 
 *  published by the Free Software Foundation; either version 2 of the
 *  License, or (at your option) any later version. 
 *
 *  This program 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
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 *  USA.
 */
package edu.udo.cs.yale.operator;

import java.util.ResourceBundle;
import java.text.MessageFormat;

/** Exception class whose instances are thrown due to a user error, for example missing files or wrong 
 *  operator architecture.
 *  <br>
 *  In order to create a UserError, do the following:
 *  <ul>
 *    <li>Open the file <code>UserErrorMessages.properties</code> in the <code>resources</code> directory.
 *        Look for an appropriate messsage. If you find one, remember its id number. If not, create a new
 *        one in the correct group</li>
 *    <li>The entry must include name, short message and long message. The name and long message will
 *        be presented to the user litarally. The short message will be parsed by 
 *        <code>java.text.MessageFormat</code>. Especially, any ocurrence of curly brackets will be
 *        replaced. Be careful with quotes; it might be a good idea to read the ducumentation of
 *        MessageFormat first.</li>
 *    <li>Create a UserError by using this id. If the UserError is created because 
 *        of another exception, e.g. a FileNotFoundException, this exception should be passed
 *        to the UserError in the constructor.</li>
 *  </ul>
 *
 *  @version $Id: UserError.java,v 2.6 2003/07/30 12:38:14 fischer Exp $
 */
public class UserError extends OperatorException {

    private static ResourceBundle messages = null;
    private static final MessageFormat formatter = new MessageFormat("");

    static {
	try {
	    messages = ResourceBundle.getBundle("edu.udo.cs.yale.resources.UserErrorMessages");	
	} catch (Throwable t) {
	    t.printStackTrace();
	}
    }

    private int code;
    private Operator operator;

    /** Creates a new UserError. 
     *  @param operator The {@link Operator} in which the exception occured
     *  @param cause The exception that caused the user error. May be null. Using this
     *         makes debugging a lot easier.
     *  @param code The error code referring to a message in the file 
     *         <code>UserErrorMessages.properties</code>
     *  @param arguments Arguments for the short message.
     */
    public UserError(Operator operator, Throwable cause, int code, Object[] arguments) { 
	super(getErrorMessage(code, arguments), cause);
	this.code = code;
	this.operator = operator;
    }

    /** Convenience constructor for messages with no arguments and cause. */
    public UserError(Operator operator, Throwable cause, int code) { 
	this(operator, code, new Object[0], cause);
    }

    public UserError(Operator operator, int code, Object[] arguments) {
	this(operator, null, code, arguments);
    }

    /** Convenience constructor for messages with exactly one argument. */
    public UserError(Operator operator, int code, Object argument1) {
	this(operator, null, code, new Object[] {argument1});
    }

    /** Convenience constructor for messages with exactly two arguments and cause. */
    public UserError(Operator operator, Throwable cause, int code, Object argument1) {
	this(operator, cause, code, new Object[] {argument1});
    }

    /** Convenience constructor for messages with exactly two arguments. */
    public UserError(Operator operator, int code, Object argument1, Object argument2) { 
	this(operator, null, code, new Object[] {argument1, argument2} );
    }

    public String getDetails() {
	return getResourceString(code, "long", "Description missing.");
    }

    public String getErrorName() {
	return getResourceString(code, "name", "Unnamed error.");
    }

    public int getCode() {
	return code;
    }

    public Operator getOperator() {
	return operator;
    }

    private static String getErrorMessage(int code, Object[] arguments) {
	String message = getResourceString(code, "short", "No message.");
	try {
	    formatter.applyPattern(message);
	    String formatted = formatter.format(arguments);
	    return formatted;
	} catch (Throwable t) {
	    return message;
	}
    }

    private static String getResourceString(int code, String key, String deflt) {
	if (messages == null) return deflt;
	try {
	    return messages.getString("error."+code+"."+key);
	} catch (java.util.MissingResourceException e) {
	    return deflt;
	}
    }
}