org.eclipse.osbp.preferences/src/org/eclipse/osbp/preferences/ProductInstanceScope.java

/**
 *                                                                            
 * Copyright (c) 2011, 2016 - Loetz GmbH&Co.KG (69115 Heidelberg, Germany)
 *                                                                            
 * 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:   
 * Christophe Loetz (Loetz GmbH&Co.KG) - initial implementation 
 */
package org.eclipse.osbp.preferences;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import org.eclipse.core.internal.preferences.AbstractScope;
import org.eclipse.core.internal.preferences.InstancePreferences;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.preferences.IEclipsePreferences;
import org.eclipse.core.runtime.preferences.InstanceScope;
import org.osgi.service.prefs.BackingStoreException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public final class ProductInstanceScope extends AbstractScope {

	private static final Logger LOGGER = LoggerFactory.getLogger(ProductInstanceScope.class);
	
	public static final String SCOPE = InstanceScope.SCOPE;
	
	private static final String DEFAULT_FILE = "DEFAULTFILE";
	
	private final String productConfigurationFile;
	
	/**
	 * Create and return a new project scope for the given project. The given
	 * project must not be <code>null</code>.
	 * 
	 * @exception IllegalArgumentException if the project is <code>null</code>
	 */
	public ProductInstanceScope() {
		String property = System.getProperty("productConfigurationFile");
		productConfigurationFile = property == null ? null : property.replaceAll(DEFAULT_FILE, ProductConfigurationPrefs.PREFERENCES_FULL_PATH);
	}

	/*
	 * @see org.eclipse.core.runtime.preferences.IScopeContext#getLocation()
	 */
	@Override
	public IPath getLocation() {
		return productConfigurationFile == null ? null : new Path(productConfigurationFile);
	}

	/*
	 * @see org.eclipse.core.runtime.IScopeContext#getNode(java.lang.String)
	 */
	@Override
	public IEclipsePreferences getNode(String qualifier) {
		if (qualifier == null)
			throw new IllegalArgumentException();
		IEclipsePreferences preference = super.getNode(qualifier);
		if	(productConfigurationFile != null) {
		    try {
			    Class<?> preferenceClass = preference.getClass();
			    Method getLoadLevel = preferenceClass.getDeclaredMethod("getLoadLevel");
			    getLoadLevel.setAccessible(true);
			    InstancePreferences loadLevelInstance = (InstancePreferences) getLoadLevel.invoke(preference);
			    Class<?>loadLevelClass = loadLevelInstance.getClass();
			    Field locationField = loadLevelClass.getDeclaredField("location");
			    locationField.setAccessible(true);
			    IPath activeLocation = (IPath) locationField.get(loadLevelInstance);
			    if	((activeLocation == null) || !activeLocation.toOSString().equals(getLocation().toOSString())) {
			    	locationField.set(loadLevelInstance, getLocation());
			    	preference.sync();
			    	LOGGER.info("set preference file to: "+getLocation().toOSString());
			    }
		    	preference.sync();
			}
		    catch (NoSuchFieldException | IllegalArgumentException | IllegalAccessException | BackingStoreException | NoSuchMethodException | SecurityException | InvocationTargetException x) {
		    	LOGGER.error("exception while trying to check and set preference file", x);
			}
		}
		return preference;
	}

	/*
	 * @see org.eclipse.core.runtime.preferences.IScopeContext#getName()
	 */
	@Override
	public String getName() {
		return SCOPE;
	}
}