fiore@0: /*  
fiore@0:  CCmI Editor - A Collaborative Cross-Modal Diagram Editing Tool
fiore@0: 	  
fiore@0:  Copyright (C) 2002 Cay S. Horstmann (http://horstmann.com)
fiore@0:  Copyright (C) 2011  Queen Mary University of London (http://ccmi.eecs.qmul.ac.uk/)
fiore@0: 
fiore@0:  This program is free software: you can redistribute it and/or modify
fiore@0:  it under the terms of the GNU General Public License as published by
fiore@0:  the Free Software Foundation, either version 3 of the License, or
fiore@0:  (at your option) any later version.
fiore@0: 
fiore@0:  This program is distributed in the hope that it will be useful,
fiore@0:  but WITHOUT ANY WARRANTY; without even the implied warranty of
fiore@0:  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
fiore@0:  GNU General Public License for more details.
fiore@0: 
fiore@0:  You should have received a copy of the GNU General Public License
fiore@0:  along with this program.  If not, see <http://www.gnu.org/licenses/>.
fiore@0: */
fiore@0: 
fiore@0: package uk.ac.qmul.eecs.ccmi.utils;
fiore@0: 
fiore@0: import java.util.prefs.Preferences;
fiore@0: 
fiore@0: /**
fiore@0:  * A service for storing and loading user preferences.
fiore@0:  */
fiore@0: public abstract class PreferencesService
fiore@0: {
fiore@0:    /**
fiore@0:     * Gets an instance of the service, suitable for the package of the given class.
fiore@0:     * @return an instance of the service
fiore@0:     */
fiore@0:    public static PreferencesService getInstance(){
fiore@0:       if (service != null) return service;
fiore@0:       try{
fiore@0:          service = new DefaultPreferencesService();
fiore@0:          return service;
fiore@0:       }
fiore@0:       catch (SecurityException exception){
fiore@5:          throw new RuntimeException(exception);      
fiore@0:       }
fiore@0:    }
fiore@0:    
fiore@0:    /**
fiore@0:     * Gets a previously stored string from the service.
fiore@0:     * @param key the key of the string
fiore@0:     * @param defval the value to return if no matching value was found
fiore@0:     * @return the value stored with the given key, or defval if none was found 
fiore@0:     */
fiore@0:    public abstract String get(String key, String defval);
fiore@0:    /**
fiore@0:     * Saves a key/value pair for later retrieval.
fiore@0:     * @param key the key of the string to be stored
fiore@0:     * @param value the value to to be stored
fiore@0:     */
fiore@0:    public abstract void put(String key, String value);
fiore@0:    
fiore@0:    private static PreferencesService service;
fiore@0: }
fiore@0: 
fiore@0: /**
fiore@0:  * The default preferences service that uses the java.util.prefs API. 
fiore@0:  */
fiore@0: class DefaultPreferencesService extends PreferencesService{   
fiore@0: 
fiore@5: 	public DefaultPreferencesService(){
fiore@5: 		prefs = Preferences.userNodeForPackage(this.getClass());   
fiore@5: 	}
fiore@5: 
fiore@5: 	@Override
fiore@5: 	public String get(String key, String defval) { return prefs.get(key, defval); }
fiore@5: 	@Override
fiore@5: 	public void put(String key, String defval) { prefs.put(key, defval); }
fiore@5: 
fiore@5: 	private Preferences prefs;
fiore@0: }