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.adapter; import static com.jgoodies.common.base.Preconditions.checkArgument; import static com.jgoodies.common.base.Preconditions.checkNotNull; import static com.jgoodies.common.internal.Messages.MUST_NOT_BE_NULL; import java.beans.PropertyChangeEvent; import java.beans.PropertyChangeListener; import javax.swing.JToggleButton; import com.jgoodies.binding.value.ValueModel; import com.jgoodies.common.base.Objects; /** * Converts ValueModels to the ToggleButtonModel interface. Useful to bind * JToggleButton, JCheckBox and JCheckBoxMenuItem to a ValueModel.<p> * * This adapter holds two values that represent the selected and the deselected * state. These are used to determine the selection state if the underlying * subject ValueModel changes its value. If the selection is set, the * corresponding representant is written to the underlying ValueModel.<p> * * <strong>Constraints:</strong> The subject ValueModel must allow * read-access to its value. Also, it is strongly recommended (though not * required) that the underlying ValueModel provides only two values, for * example Boolean.TRUE and Boolean.FALSE. This is so because the toggle button * component may behave "strangely" when it is used with ValueModels that * provide more than two elements.<p> * * <strong>Examples:</strong><pre> * // Recommended binding style using a factory * ValueModel model = presentationModel.getModel(MyBean.PROPERTY_VISIBLE); * JCheckBox visibleBox = BasicComponentFactory.createCheckBox(model, "Visible"); * * // Binding using the Bindings class * ValueModel model = presentationModel.getModel(MyBean.PROPERTY_VISIBLE); * JCheckBox visibleBox = new JCheckBox("Visible"); * Bindings.bind(visibleBox, model); * * // Hand-made binding * ValueModel model = presentationModel.getModel(MyBean.PROPERTY_VISIBLE); * JCheckBox visibleBox = new JCheckBox("Visible"); * visibleBox.setModel(new ToggleButtonAdapter(model)); * </pre> * * @author Karsten Lentzsch * @version $Revision: 1.12 $ * * @see javax.swing.ButtonModel * @see javax.swing.JCheckBox * @see javax.swing.JCheckBoxMenuItem */ public final class ToggleButtonAdapter extends JToggleButton.ToggleButtonModel { /** * Refers to the underlying ValueModel that is used to read and write values. */ private final ValueModel subject; /** * The value that represents the selected state. */ private final Object selectedValue; /** * The value that represents the deselected state. */ private final Object deselectedValue; // Instance Creation ***************************************************** /** * Constructs a ToggleButtonAdapter on the given subject ValueModel. * The created adapter will be selected if and only if the * subject's initial value is {@code Boolean.TRUE}. * * @param subject the subject that holds the value * @throws NullPointerException if the subject is {@code null}. */ public ToggleButtonAdapter(ValueModel subject) { this(subject, Boolean.TRUE, Boolean.FALSE); } /** * Constructs a ToggleButtonAdapter on the given subject ValueModel * using the specified values for the selected and deselected state. * The created adapter will be selected if and only if the * subject's initial value equals the given {@code selectedValue}. * * @param subject the subject that holds the value * @param selectedValue the value that will be set if this is selected * @param deselectedValue the value that will be set if this is deselected * * @throws NullPointerException if the subject is {@code null}. * @throws IllegalArgumentException if the selected and deselected values * are equal */ public ToggleButtonAdapter(ValueModel subject, Object selectedValue, Object deselectedValue) { this.subject = checkNotNull(subject, MUST_NOT_BE_NULL, "subject"); checkArgument(!Objects.equals(selectedValue, deselectedValue), "The selected value must not equal the deselected value."); this.selectedValue = selectedValue; this.deselectedValue = deselectedValue; subject.addValueChangeListener(new SubjectValueChangeHandler()); updateSelectedState(); } // ToggleButtonModel Implementation *********************************** /** * First, the subject value is set to this adapter's selected value if * the argument is {@code true}, to the deselected value otherwise. * Second, this adapter's state is set to the then current subject value. * This ensures that the selected state is synchronized with the subject * - even if the subject rejects the change. * * @param b {@code true} sets the selected value as subject value, * {@code false} sets the deselected value as subject value */ @Override public void setSelected(boolean b) { subject.setValue(b ? selectedValue : deselectedValue); updateSelectedState(); } /** * Updates this adapter's selected state to reflect * whether the subject holds the selected value or not. * Does not modify the subject value. */ private void updateSelectedState() { boolean subjectHoldsChoiceValue = Objects.equals(selectedValue, subject.getValue()); super.setSelected(subjectHoldsChoiceValue); } // Event Handling ********************************************************* /** * Handles changes in the subject's value. */ private final class SubjectValueChangeHandler implements PropertyChangeListener { /** * The subject value has changed. Updates this adapter's selected * state to reflect whether the subject holds the selected value or not. * * @param evt the property change event fired by the subject */ @Override public void propertyChange(PropertyChangeEvent evt) { updateSelectedState(); } } }