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13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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25 
26 package javax.swing.plaf.metal;
27 
28 import javax.swing.*;
29 import javax.swing.event.*;
30 import javax.swing.border.*;
31 import javax.swing.plaf.*;
32 import javax.swing.plaf.basic.*;
33 
34 import java.awt.*;
35 import java.beans.*;
36 import java.awt.event.*;
37 
38 
39 /**
40  * A Metal L&F implementation of ScrollPaneUI.
41  * <p>
42  * <strong>Warning:</strong>
43  * Serialized objects of this class will not be compatible with
44  * future Swing releases. The current serialization support is
45  * appropriate for short term storage or RMI between applications running
46  * the same version of Swing.  As of 1.4, support for long term storage
47  * of all JavaBeans&trade;
48  * has been added to the <code>java.beans</code> package.
49  * Please see {@link java.beans.XMLEncoder}.
50  *
51  * @author Steve Wilson
52  */
53 @SuppressWarnings("serial") // Same-version serialization only
54 public class MetalScrollPaneUI extends BasicScrollPaneUI
55 {
56 
57     private PropertyChangeListener scrollBarSwapListener;
58 
59     /**
60      * Constructs a new {@code MetalScrollPaneUI}.
61      *
62      * @param x a component
63      * @return a new {@code MetalScrollPaneUI}
64      */
createUI(JComponent x)65     public static ComponentUI createUI(JComponent x) {
66         return new MetalScrollPaneUI();
67     }
68 
installUI(JComponent c)69     public void installUI(JComponent c) {
70 
71         super.installUI(c);
72 
73         JScrollPane sp = (JScrollPane)c;
74         updateScrollbarsFreeStanding();
75     }
76 
uninstallUI(JComponent c)77     public void uninstallUI(JComponent c) {
78         super.uninstallUI(c);
79 
80         JScrollPane sp = (JScrollPane)c;
81         JScrollBar hsb = sp.getHorizontalScrollBar();
82         JScrollBar vsb = sp.getVerticalScrollBar();
83         if (hsb != null) {
84             hsb.putClientProperty( MetalScrollBarUI.FREE_STANDING_PROP, null);
85         }
86         if (vsb != null) {
87             vsb.putClientProperty( MetalScrollBarUI.FREE_STANDING_PROP, null);
88         }
89     }
90 
installListeners(JScrollPane scrollPane)91     public void installListeners(JScrollPane scrollPane) {
92         super.installListeners(scrollPane);
93         scrollBarSwapListener = createScrollBarSwapListener();
94         scrollPane.addPropertyChangeListener(scrollBarSwapListener);
95     }
96 
97     /**
98      * {@inheritDoc}
99      */
uninstallListeners(JComponent c)100     protected void uninstallListeners(JComponent c) {
101         super.uninstallListeners(c);
102         c.removePropertyChangeListener(scrollBarSwapListener);
103     }
104 
105     /**
106      * @param scrollPane an instance of the {@code JScrollPane}
107      * @deprecated - Replaced by {@link #uninstallListeners(JComponent)}
108      */
109     @Deprecated
uninstallListeners(JScrollPane scrollPane)110     public void uninstallListeners(JScrollPane scrollPane) {
111         super.uninstallListeners(scrollPane);
112         scrollPane.removePropertyChangeListener(scrollBarSwapListener);
113     }
114 
115     /**
116      * If the border of the scrollpane is an instance of
117      * <code>MetalBorders.ScrollPaneBorder</code>, the client property
118      * <code>FREE_STANDING_PROP</code> of the scrollbars
119      * is set to false, otherwise it is set to true.
120      */
updateScrollbarsFreeStanding()121     private void updateScrollbarsFreeStanding() {
122         if (scrollpane == null) {
123             return;
124         }
125         Border border = scrollpane.getBorder();
126         Object value;
127 
128         if (border instanceof MetalBorders.ScrollPaneBorder) {
129             value = Boolean.FALSE;
130         }
131         else {
132             value = Boolean.TRUE;
133         }
134         JScrollBar sb = scrollpane.getHorizontalScrollBar();
135         if (sb != null) {
136             sb.putClientProperty
137                    (MetalScrollBarUI.FREE_STANDING_PROP, value);
138         }
139         sb = scrollpane.getVerticalScrollBar();
140         if (sb != null) {
141             sb.putClientProperty
142                    (MetalScrollBarUI.FREE_STANDING_PROP, value);
143         }
144     }
145 
146     /**
147      * Returns a new {@code PropertyChangeListener} for scroll bar swap events.
148      *
149      * @return a new {@code PropertyChangeListener} for scroll bar swap events.
150      */
createScrollBarSwapListener()151     protected PropertyChangeListener createScrollBarSwapListener() {
152         return new PropertyChangeListener() {
153             public void propertyChange(PropertyChangeEvent e) {
154                   String propertyName = e.getPropertyName();
155                   if (propertyName.equals("verticalScrollBar") ||
156                       propertyName.equals("horizontalScrollBar")) {
157                       JScrollBar oldSB = (JScrollBar)e.getOldValue();
158                       if (oldSB != null) {
159                           oldSB.putClientProperty(
160                               MetalScrollBarUI.FREE_STANDING_PROP, null);
161                       }
162                       JScrollBar newSB = (JScrollBar)e.getNewValue();
163                       if (newSB != null) {
164                           newSB.putClientProperty(
165                               MetalScrollBarUI.FREE_STANDING_PROP,
166                               Boolean.FALSE);
167                       }
168                   }
169                   else if ("border".equals(propertyName)) {
170                       updateScrollbarsFreeStanding();
171                   }
172         }};
173     }
174 
175 }
176