package net.sourceforge.squirrel_sql.client.session.mainpanel;
/*
 * Copyright (C) 2001-2003 Colin Bell
 * colbell@users.sourceforge.net
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser 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
 */
import net.sourceforge.squirrel_sql.fw.util.log.ILogger;
import net.sourceforge.squirrel_sql.fw.util.log.LoggerController;

import net.sourceforge.squirrel_sql.client.session.ISession;

import java.awt.*;

/**
 * Base class for tabs to the added to the main tabbed panel.
 *
 * @author <A HREF="mailto:colbell@users.sourceforge.net">Colin Bell</A>
 */
public abstract class BaseMainPanelTab implements IMainPanelTab
{
	/** Logger for this class. */
	private static ILogger s_log =
		LoggerController.createLogger(BaseMainPanelTab.class);

	/** Current session. */
	private ISession _session;

	/** Set to <TT>true</TT> once this tab has been displayed. */
	private boolean _hasBeenDisplayed;

	/**
	 * Set the current session.
	 *
	 * @param	session	Current session.
	 *
	 * @throws	IllegalArgumentException
	 *			Thrown if a <TT>null</TT> ISession</TT> passed.
	 */
	public void setSession(ISession session)
	{
		if (session == null)
		{
			throw new IllegalArgumentException("Null ISession passed");
		}
		_session = session;
	}

	/**
	 * The current session is closing.
	 *
	 * @param	session		Current session.
	 */
	public void sessionClosing(ISession session)
	{
		// Empty method.
	}

	/**
	 * Retrieve the current session.
	 *
	 * @return	Current session.
	 */
	public final ISession getSession()
	{
		return _session;
	}

	/**
	 * This tab has been selected. This will call <TT>refreshComponent()</TT>
	 * only if it hasn't been called.
	 */
	public synchronized void select()
	{
		if (!_hasBeenDisplayed)
		{
			s_log.debug("Refreshing " + getTitle() + " main tab.");
			refreshComponent();
			_hasBeenDisplayed = true;
		}
	}

   @Override
   public Component getTabComponent()
   {
      return null;
   }

   /**
	 * Refresh the component.
	 */
	protected abstract void refreshComponent();
    
    /**
     * When a session is ending, if it happens to be the one this class is using,
     * then set our reference to null to allow it to be GC'd.
     * 
     * @param session the session that is ending.
     */
    public void sessionEnding(ISession session) {
        if (_session == session) {
            _session = null;
        }
    }
}