Java tutorial
/* * Copyright (c) 2008, SQL Power Group Inc. * * This file is part of SQL Power Library. * * SQL Power Library 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 3 of the License, or * (at your option) any later version. * * SQL Power Library 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, see <http://www.gnu.org/licenses/>. */ package ca.sqlpower.object.undo; import java.beans.PropertyChangeEvent; import java.beans.PropertyDescriptor; import java.lang.reflect.Method; import javax.swing.undo.AbstractUndoableEdit; import javax.swing.undo.CannotRedoException; import javax.swing.undo.CannotUndoException; import org.apache.commons.beanutils.PropertyUtils; import org.apache.log4j.Logger; /** * This is the generic edit class that dynamically modifies bean properties * according to the PropertyChangeEvent source and the property name. * * @author kaiyi * */ public class PropertyChangeEdit extends AbstractUndoableEdit { private static final Logger logger = Logger.getLogger(PropertyChangeEdit.class); private final PropertyChangeEvent sourceEvent; public PropertyChangeEdit(PropertyChangeEvent e) { this.sourceEvent = e; } /** * Sets the value of the property to be the old value */ @Override public void undo() throws CannotUndoException { logger.debug("Undoing Property change: Setting " + sourceEvent.getPropertyName() + " from " + sourceEvent.getNewValue() + " to " + sourceEvent.getOldValue()); super.undo(); try { final PropertyDescriptor propertyDescriptor = PropertyUtils .getPropertyDescriptor(sourceEvent.getSource(), sourceEvent.getPropertyName()); logger.debug("Found property descriptor " + propertyDescriptor); if (logger.isDebugEnabled()) { PropertyDescriptor[] propertyDescriptors = PropertyUtils .getPropertyDescriptors(sourceEvent.getSource()); logger.debug("Descriptor has write method " + propertyDescriptor.getWriteMethod()); } Method setter = PropertyUtils.getWriteMethod(propertyDescriptor); logger.info("Found setter: " + setter.getName()); setter.invoke(sourceEvent.getSource(), sourceEvent.getOldValue()); } catch (Exception ex) { CannotUndoException wrapper = new CannotUndoException(); wrapper.initCause(ex); throw wrapper; } } /** * Sets the value of the property to be the new value */ @Override public void redo() throws CannotRedoException { logger.debug("Undoing Property change: Setting " + sourceEvent.getPropertyName() + " from " + sourceEvent.getOldValue() + " to " + sourceEvent.getNewValue()); super.redo(); try { Method setter = PropertyUtils.getWriteMethod( PropertyUtils.getPropertyDescriptor(sourceEvent.getSource(), sourceEvent.getPropertyName())); logger.info("Found setter: " + setter.getName()); setter.invoke(sourceEvent.getSource(), sourceEvent.getNewValue()); } catch (Exception ex) { CannotRedoException wrapper = new CannotRedoException(); wrapper.initCause(ex); throw wrapper; } } @Override public String getPresentationName() { return "property change edit"; } /** * Returns the name of the property that this edit represents a change to. */ public String getPropertyName() { return sourceEvent.getPropertyName(); } /** * Returns the property's new value. This is the value that this edit will redo to. */ public Object getNewValue() { return sourceEvent.getNewValue(); } /** * Returns the property's old value. This is the value that this edit will undo to. */ public Object getOldValue() { return sourceEvent.getOldValue(); } /** * Returns the object whose property changed. * @return */ public Object getSource() { return sourceEvent.getSource(); } @Override public String toString() { return "Changing property: \"" + sourceEvent.getPropertyName() + "\" by " + sourceEvent; } }