UrlSerializer.java

/*******************************************************************************
 * Copyright (c) 2006 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     IBM Research
 *******************************************************************************/
package com.ibm.research.tagging.url;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.net.MalformedURLException;
import java.net.URL;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import org.eclipse.core.runtime.IPath;
import org.eclipse.ui.IMemento;
import org.eclipse.ui.WorkbenchException;
import org.eclipse.ui.XMLMemento;

import com.ibm.research.tagging.core.ITag;
import com.ibm.research.tagging.core.ITagCore;
import com.ibm.research.tagging.core.IWaypoint;

/**
 * @author mdesmond
 */
public class UrlSerializer 
{	
	private static final String URL_FILE = "url.repository.xml";
	private static final String DOC_ROOT = "url-repository";

	private static final String NAME_ATTRIBUTE = "name";
	private static final String TAG = "tag";

	private static final String URL_WAYPOINT = "url-waypoint";
	private static final String URL_ATTRIBUTE = "url";
	private static final String DESCRIPTION_ATTRIBUTE = "description";
	private static final String AUTHOR_ATTRIBUTE = "author";
	private static final String DATE_ATTRIBUTE = "date";

	public void serialize(ITagCore model)
	{
		XMLMemento memento = XMLMemento.createWriteRoot(DOC_ROOT);
		writeMemento(model, memento);
		writeMementoToDisk(memento);
	}

	private void writeMemento(ITagCore model, IMemento memento)
	{
		IWaypoint[] waypoints = model.getWaypointModel().getWaypoints();

		for(IWaypoint waypoint : waypoints)
		{
			if(waypoint.getType().equals(UrlWaypoint.TYPE))
			{
				UrlWaypoint webWaypoint = (UrlWaypoint)waypoint;

				IMemento waypointMemento = memento.createChild(URL_WAYPOINT);

				waypointMemento.putString(URL_ATTRIBUTE, webWaypoint.getURL());
				waypointMemento.putString(AUTHOR_ATTRIBUTE, webWaypoint.getAuthor());

				if(webWaypoint.getDate()!=null )
				{
					SimpleDateFormat format = new SimpleDateFormat();
					String dateString = format.format(webWaypoint.getDate());
					waypointMemento.putString(DATE_ATTRIBUTE, dateString);
				}

				waypointMemento.putString(DESCRIPTION_ATTRIBUTE, webWaypoint.getDescription());

				ITag[] tags = webWaypoint.getTags();

				for(ITag tag : tags)
				{
					IMemento tagMemento = waypointMemento.createChild(TAG);
					tagMemento.putString(NAME_ATTRIBUTE, tag.getName());
				}

			}
		} 
	}

	private void writeMementoToDisk(XMLMemento memento) 
	{
		IPath path = UrlWaypointPlugin.getDefault().getStateLocation().append(URL_FILE);
		File mementoFile = path.toFile();
		mementoFile.getParentFile().mkdirs();

		try
		{		
			FileOutputStream stream = new FileOutputStream(mementoFile);
			OutputStreamWriter writer = new OutputStreamWriter(stream, "utf-8"); //$NON-NLS-1$
			memento.save(writer);
			writer.close();
		}
		catch (IOException e) 
		{
			e.printStackTrace();
		}
	}

	public void deSerialize(ITagCore model)
	{
		IPath path = UrlWaypointPlugin.getDefault().getStateLocation().append(URL_FILE);		
		File mementoFile = path.toFile();

		if(mementoFile.exists())
		{
			try 
			{
				FileInputStream input = new FileInputStream(mementoFile);
				BufferedReader reader = new BufferedReader(new InputStreamReader(input, "utf-8")); //$NON-NLS-1$
				IMemento memento = XMLMemento.createReadRoot(reader);			
				restoreStateFromMemento(model,memento);
			} 
			catch (FileNotFoundException e) 
			{
				e.printStackTrace();
			} 
			catch (UnsupportedEncodingException e) 
			{
				e.printStackTrace();
			} 
			catch (WorkbenchException e) 
			{
				e.printStackTrace();
			}
		}
	}

	private static void restoreStateFromMemento(ITagCore model, IMemento memento) 
	{	
		IMemento[] urlMementos = memento.getChildren(URL_WAYPOINT);

		for (IMemento urlMemento : urlMementos) 
		{
			String urlString = urlMemento.getString(URL_ATTRIBUTE);

			if(urlString!=null)
			{
				String author = urlMemento.getString(AUTHOR_ATTRIBUTE);
				String dateString = urlMemento.getString(DATE_ATTRIBUTE);
				String description = urlMemento.getString(DESCRIPTION_ATTRIBUTE);

				String[] tagNames = getTagNames(urlMemento);

				Date date = null;
				if(dateString!=null)
				{
					try 
					{
						date = SimpleDateFormat.getInstance().parse(dateString);
					} 
					catch (ParseException e) 
					{
						e.printStackTrace();
					}
				}
				
				UrlWaypoint waypoint = new UrlWaypoint(urlString,description,author,date);

				for(String tagName : tagNames)
				{
					ITag tag = model.getTagModel().addTag(tagName);
					waypoint.addTag(tag);
				}

				model.getWaypointModel().addWaypoint(waypoint);
			}
		}
	}

	private static String[] getTagNames(IMemento urlMemento) 
	{
		IMemento[] tagMementos = urlMemento.getChildren(TAG);
		List<String> tags = new ArrayList<String>();

		for(IMemento tagMemento : tagMementos)
		{
			String tagName = tagMemento.getString(NAME_ATTRIBUTE);

			if(tagName!=null)
				tags.add(tagName);
		}

		String[] array = new String[0];
		return tags.toArray(array);
	}
}