Java tutorial
/* * Copyright (c) 2010, 2017, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code 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 * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javafx.scene.control; import java.util.HashMap; import java.util.List; import javafx.beans.property.ReadOnlyObjectProperty; import javafx.beans.property.ReadOnlyObjectWrapper; import javafx.collections.ListChangeListener.Change; import javafx.collections.FXCollections; import javafx.collections.ObservableList; import javafx.collections.ObservableMap; import com.sun.javafx.collections.VetoableListDecorator; import com.sun.javafx.collections.TrackableObservableList; /** * A class which contains a reference to all {@code Toggles} whose * {@code selected} variables should be managed such that only a single * <code>{@link Toggle}</code> within the {@code ToggleGroup} may be selected at * any one time. * <p> * Generally {@code ToggleGroups} are managed automatically simply by specifying * the name of a {@code ToggleGroup} on the <code>{@link Toggle}</code>, but in * some situations it is desirable to explicitly manage which * {@code ToggleGroup} is used by <code>{@link Toggle Toggles}</code>. * </p> * @since JavaFX 2.0 */ public class ToggleGroup { /** * Creates a default ToggleGroup instance. */ public ToggleGroup() { } /** * The list of toggles within the ToggleGroup. * @return the list of toggles within the ToggleGroup */ public final ObservableList<Toggle> getToggles() { return toggles; } private final ObservableList<Toggle> toggles = new VetoableListDecorator<Toggle>( new TrackableObservableList<Toggle>() { @Override protected void onChanged(Change<Toggle> c) { while (c.next()) { // Look through the removed toggles, and if any of them was the // one and only selected toggle, then we will clear the selected // toggle property. for (Toggle t : c.getRemoved()) { if (t.isSelected()) { selectToggle(null); } } // A Toggle can only be in one group at any one time. If the // group is changed, then the toggle is removed from the old group prior to // being added to the new group. for (Toggle t : c.getAddedSubList()) { if (!ToggleGroup.this.equals(t.getToggleGroup())) { if (t.getToggleGroup() != null) { t.getToggleGroup().getToggles().remove(t); } t.setToggleGroup(ToggleGroup.this); } } // Look through all the added toggles and the very first selected // toggle we encounter will become the one we make the selected // toggle for this group. for (Toggle t : c.getAddedSubList()) { if (t.isSelected()) { selectToggle(t); break; } } } } }) { @Override protected void onProposedChange(List<Toggle> toBeAdded, int... indexes) { for (Toggle t : toBeAdded) { if (indexes[0] == 0 && indexes[1] == size()) { // we don't need to check for duplicates because this is a setAll. break; } if (toggles.contains(t)) { throw new IllegalArgumentException("Duplicate toggles are not allow in a ToggleGroup."); } } } }; private final ReadOnlyObjectWrapper<Toggle> selectedToggle = new ReadOnlyObjectWrapper<Toggle>() { // Note: "set" is really what I want here. If the selectedToggle property // is bound, then this whole chunk of code is bypassed, which is exactly // what I want to do. @Override public void set(final Toggle newSelectedToggle) { if (isBound()) { throw new java.lang.RuntimeException("A bound value cannot be set."); } final Toggle old = get(); if (old == newSelectedToggle) { return; } if (setSelected(newSelectedToggle, true) || (newSelectedToggle != null && newSelectedToggle.getToggleGroup() == ToggleGroup.this) || (newSelectedToggle == null)) { if (old == null || old.getToggleGroup() == ToggleGroup.this || !old.isSelected()) { setSelected(old, false); } super.set(newSelectedToggle); } } }; /** * Selects the toggle. * * @param value The {@code Toggle} that is to be selected. */ // Note that since selectedToggle is a read-only property, the selectToggle method is some // other method than setSelectedToggle, even though it is in essence doing the same thing public final void selectToggle(Toggle value) { selectedToggle.set(value); } /** * Gets the selected {@code Toggle}. * @return Toggle The selected toggle. */ public final Toggle getSelectedToggle() { return selectedToggle.get(); } /** * The selected toggle. * @return the selected toggle */ public final ReadOnlyObjectProperty<Toggle> selectedToggleProperty() { return selectedToggle.getReadOnlyProperty(); } private boolean setSelected(Toggle toggle, boolean selected) { if (toggle != null && toggle.getToggleGroup() == this && !toggle.selectedProperty().isBound()) { toggle.setSelected(selected); return true; } return false; } // Clear the selected toggle only if there are no other toggles selected. final void clearSelectedToggle() { if (!selectedToggle.getValue().isSelected()) { for (Toggle toggle : getToggles()) { if (toggle.isSelected()) { return; } } } selectedToggle.set(null); } /************************************************************************* * * * * * * *************************************************************************/ private static final Object USER_DATA_KEY = new Object(); // A map containing a set of properties for this scene private ObservableMap<Object, Object> properties; /** * Returns an observable map of properties on this node for use primarily * by application developers. * * @return an observable map of properties on this node for use primarily * by application developers * * @since JavaFX 8u40 */ public final ObservableMap<Object, Object> getProperties() { if (properties == null) { properties = FXCollections.observableMap(new HashMap<Object, Object>()); } return properties; } /** * Tests if ToggleGroup has properties. * @return true if node has properties. * * @since JavaFX 8u40 */ public boolean hasProperties() { return properties != null && !properties.isEmpty(); } /** * Convenience method for setting a single Object property that can be * retrieved at a later date. This is functionally equivalent to calling * the getProperties().put(Object key, Object value) method. This can later * be retrieved by calling {@link ToggleGroup#getUserData()}. * * @param value The value to be stored - this can later be retrieved by calling * {@link ToggleGroup#getUserData()}. * * @since JavaFX 8u40 */ public void setUserData(Object value) { getProperties().put(USER_DATA_KEY, value); } /** * Returns a previously set Object property, or null if no such property * has been set using the {@link ToggleGroup#setUserData(java.lang.Object)} method. * * @return The Object that was previously set, or null if no property * has been set or if null was set. * * @since JavaFX 8u40 */ public Object getUserData() { return getProperties().get(USER_DATA_KEY); } }