Java tutorial
/* * Copyright (c) 2002-2015 JGoodies Software GmbH. All Rights Reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * o Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * o Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * o Neither the name of JGoodies Software GmbH nor the names of * its contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ package com.jgoodies.binding.beans; import java.beans.PropertyChangeListener; import java.beans.PropertyChangeSupport; import java.beans.VetoableChangeListener; import java.beans.VetoableChangeSupport; import com.jgoodies.common.bean.Bean; /** * An abstract superclass that minimizes the effort required to provide * change support for bound and constrained Bean properties. * This class follows the conventions and recommendations as described * in the <a href="http://java.sun.com/products/javabeans/docs/spec.html" * >Java Bean Specification</a>.<p> * * Uses class {@link com.jgoodies.binding.beans.ExtendedPropertyChangeSupport}, * to enable the {@code ==} or {@code #equals} test when * changing values.<p> * * TODO: Consider adding a method {@code #fireChange} that invokes * {@code #firePropertyChange} if and only if * {@code new value != old value}. The background is, that * {@code #firePropertyChange} must fire an event * if {@code new value==null==old value}.<p> * * @author Karsten Lentzsch * @version $Revision: 1.22 $ * * @see Model * @see java.beans.PropertyChangeEvent * @see PropertyChangeListener * @see PropertyChangeSupport * @see ExtendedPropertyChangeSupport * @see VetoableChangeListener * @see VetoableChangeSupport */ public abstract class Model extends Bean { // Overriding Superclass Behavior **************************************** /** * Creates and returns a PropertyChangeSupport for the given bean. * Invoked by the first call to {@link #addPropertyChangeListener} * when lazily creating the sole change support instance used throughout * this bean.<p> * * This implementation creates an extended change support that allows * to configure whether the old and new value are compared with * {@code ==} or {@code equals}. * * @param bean the bean to create a change support for * @return the new change support */ @Override protected PropertyChangeSupport createPropertyChangeSupport(Object bean) { return new ExtendedPropertyChangeSupport(bean); } // Managing Property Change Listeners ********************************** /** * Support for reporting bound property changes for Object properties. * This method can be called when a bound property has changed and it will * send the appropriate PropertyChangeEvent to any registered * PropertyChangeListeners.<p> * * The boolean parameter specifies whether the old and new value are * compared with {@code ==} or {@code equals}. * * @param propertyName the property whose value has changed * @param oldValue the property's previous value * @param newValue the property's new value * @param checkIdentity true to check differences using {@code ==} * false to use {@code equals}. */ protected final void firePropertyChange(String propertyName, Object oldValue, Object newValue, boolean checkIdentity) { if (changeSupport == null) { return; } ((ExtendedPropertyChangeSupport) changeSupport).firePropertyChange(propertyName, oldValue, newValue, checkIdentity); } }