/*
 *------------------------------------------------------------------------------
 *  Copyright (C) 2006-2008 University of Dundee. All rights reserved.
 *
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 *  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.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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package org.openmicroscopy.shoola.agents.metadata;

import org.openmicroscopy.shoola.agents.metadata.editor.Editor;
import org.openmicroscopy.shoola.env.config.Registry;
import org.openmicroscopy.shoola.env.data.events.DSCallAdapter;
import omero.gateway.SecurityContext;
import org.openmicroscopy.shoola.env.data.views.AdminView;
import org.openmicroscopy.shoola.env.data.views.DataManagerView;
import org.openmicroscopy.shoola.env.data.views.ImageDataView;
import org.openmicroscopy.shoola.env.data.views.MetadataHandlerView;
import omero.log.LogMessage;

import omero.gateway.model.ExperimenterData;
import omero.gateway.model.GroupData;

/** 
 * Parent of all classes that load data asynchronously for a {@link Editor}.
 * All these classes invoke methods of the {@link DataManagerView} or
 * {@link MetadataHandlerView} which this class makes available through a 
 * <code>protected</code> field.
 * Also, this class extends {@link DSCallAdapter} so that subclasses
 * automatically become observers to an asynchronous call.  This class provides
 * default implementations of some of the callbacks to notify the 
 * {@link Editor} of the progress and the user in the case of errors. 
 * Subclasses should at least implement the <code>handleResult</code> method 
 * to feed the {@link Editor} back with the results.
 *
 * @author  Jean-Marie Burel     
 * <a href="mailto:j.burel@dundee.ac.uk">j.burel@dundee.ac.uk</a>
 * @author Donald MacDonald     
 * <a href="mailto:donald@lifesci.dundee.ac.uk">donald@lifesci.dundee.ac.uk</a>
 * @version 3.0
 * <small>
 * (<b>Internal version:</b> $Revision: $Date: $)
 * </small>
 * @since OME3.0
 */
public abstract class EditorLoader
	extends DSCallAdapter
{

	/** The viewer this data loader is for. */
    protected final Editor viewer;
    
	/** Convenience reference for subclasses. */
    protected final Registry registry;
    
    /** Convenience reference for subclasses. */
    protected final MetadataHandlerView mhView;
    
    /** Convenience reference for subclasses. */
    protected final DataManagerView dmView;
    
    /** Convenience reference for subclasses. */
    protected final ImageDataView imView;
    
    /** Convenience reference for subclasses. */
    protected final AdminView adminView;
    
    /** The security context.*/
    protected final SecurityContext ctx;
    
    /**
     * Creates a new instance.
     * 
     * @param viewer The viewer this data loader is for.
     *               Mustn't be <code>null</code>.
     * @param ctx The security context.
     */
    public EditorLoader(Editor viewer, SecurityContext ctx)
    {
    	if (viewer == null) throw new NullPointerException("No viewer.");
    	if (ctx == null)
    		throw new NullPointerException("No security context.");
    	this.ctx = ctx;
    	this.viewer = viewer;
    	registry = MetadataViewerAgent.getRegistry();
    	mhView = (MetadataHandlerView) 
    	registry.getDataServicesView(MetadataHandlerView.class);
    	dmView = (DataManagerView) 
    	registry.getDataServicesView(DataManagerView.class);
    	imView = (ImageDataView) 
    	registry.getDataServicesView(ImageDataView.class);
    	adminView = (AdminView) registry.getDataServicesView(AdminView.class);
    }
    
    /**
     * Returns the id of the user currently logged in.
     * 
     * @return See above.
     */
    protected long getCurrentUser()
    {
    	return MetadataViewerAgent.getUserDetails().getId();
    }
    
    /**
     * Notifies the user that it wasn't possible to retrieve the data.
     */
    public void handleNullResult() 
    {
    	viewer.setStatus(false);
    	LogMessage msg = new LogMessage();
        msg.print("No data returned.");
        registry.getLogger().error(this, msg);
        //handleException(new Exception("No data available."));
    }
    
    /** Notifies the user that the data retrieval has been canceled. */
    public void handleCancellation() 
    {
        String info = "The data retrieval has been cancelled.";
        registry.getLogger().info(this, info);
        //registry.getUserNotifier().notifyInfo("Data Retrieval Cancellation", 
        //info);
    }
    
    /**
     * Notifies the user that an error has occurred and discards the 
     * {@link #viewer}.
     * @see DSCallAdapter#handleException(Throwable)
     */
    public void handleException(Throwable exc) 
    {
    	viewer.setStatus(false);
    	String s = "Data Retrieval Failure: ";
        LogMessage msg = new LogMessage();
        msg.print(s);
        msg.print(exc);
        registry.getLogger().error(this, msg);
        registry.getUserNotifier().notifyError("Data Retrieval Failure", 
                                               s, exc);
    }
    
    /** Fires an asynchronous data loading. */
    public abstract void load();
    
    /** Cancels any ongoing data loading. */
    public abstract void cancel(); 
    
}