| /******************************************************************************* |
| * Copyright (c) 2005 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 |
| *******************************************************************************/ |
| package org.eclipse.core.runtime.preferences; |
| |
| /** |
| * This class provides a hook into the preference service before particular operations |
| * on the global preference tree. Preference modify listeners are registered with |
| * the preference service via XML and the <code>org.eclipse.core.runtime.preferences</code> |
| * extension point. |
| * <p> |
| * Clients may subclass this type. |
| * </p> |
| * |
| * @since 3.1 |
| */ |
| public abstract class PreferenceModifyListener { |
| |
| /** |
| * Clients are given the opportunity to modify the given tree before it is applied |
| * to the global preference tree. Clients should return the tree which should be |
| * applied globally. The tree passed in will not be <code>null</code> and clients |
| * <em>must not</em> return a <code>null</code> tree. |
| * <p> |
| * This method is called by the preference service from within calls to |
| * {@link IPreferencesService#applyPreferences(IExportedPreferences)} or |
| * {@link IPreferencesService#applyPreferences(IEclipsePreferences, IPreferenceFilter[])}. |
| * </p> |
| * <p> |
| * A typical action for clients to perform would be to intercept the incoming preference tree, |
| * migrate old preference values to new ones, and then return the new tree. |
| * </p> |
| * |
| * @param node the tree to modify |
| * @return the tree to apply to the global preferences |
| */ |
| public IEclipsePreferences preApply(IEclipsePreferences node) { |
| // default implementation makes no modifications |
| return node; |
| } |
| |
| } |
