errorhandler.java

来自「google公司的用Java写的一个聊天软件的原代码」· Java 代码 · 共 108 行

/***************************************************************************
 *   Copyright 2006-2008 by Christian Ihle                                 *
 *   [e-mail]                                                  *
 *                                                                         *
 *   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 net.usikkert.kouchat.misc;

import java.util.ArrayList;
import java.util.List;

import net.usikkert.kouchat.event.ErrorListener;

/**
 * This is a singleton class for reporting errors to listeners.
 * These errors will be shown to the user of the application.
 *
 * @author Christian Ihle
 */
public final class ErrorHandler
{
	/**
	 * The single instance of this class.
	 */
	private static final ErrorHandler INSTANCE = new ErrorHandler();

	private final List<ErrorListener> listeners;

	/**
	 * Private constructor.
	 */
	private ErrorHandler()
	{
		listeners = new ArrayList<ErrorListener>();
	}

	/**
	 * Will return the only instance of this class.
	 *
	 * @return The only instance of ErrorHandler.
	 */
	public static ErrorHandler getErrorHandler()
	{
		return INSTANCE;
	}

	/**
	 * This method notifies the listeners that an error has occured.
	 *
	 * @param errorMsg The message to deliver to the listeners.
	 */
	public void showError( final String errorMsg )
	{
		for ( ErrorListener listener : listeners )
		{
			listener.errorReported( errorMsg );
		}
	}

	/**
	 * This method notifies the listeners that a critical error has occured.
	 *
	 * @param criticalErrorMsg The message to deliver to the listeners.
	 */
	public void showCriticalError( final String criticalErrorMsg )
	{
		for ( ErrorListener listener : listeners )
		{
			listener.criticalErrorReported( criticalErrorMsg );
		}
	}

	/**
	 * Adds a new error listener.
	 *
	 * @param listener The class to add as a listener.
	 */
	public void addErrorListener( final ErrorListener listener )
	{
		listeners.add( listener );
	}

	/**
	 * Removes an error listener.
	 *
	 * @param listener The class to remove as a listener.
	 */
	public void removeErrorListener( final ErrorListener listener )
	{
		listeners.remove( listener );
	}
}