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25 package javax.swing.text;
26 
27 import java.awt.event.ActionEvent;
28 import java.awt.KeyboardFocusManager;
29 import java.awt.Component;
30 import java.util.Hashtable;
31 import java.util.Enumeration;
32 import javax.swing.Action;
33 import javax.swing.AbstractAction;
34 import javax.swing.KeyStroke;
35 
36 /**
37  * An Action implementation useful for key bindings that are
38  * shared across a number of different text components.  Because
39  * the action is shared, it must have a way of getting it's
40  * target to act upon.  This class provides support to try and
41  * find a text component to operate on.  The preferred way of
42  * getting the component to act upon is through the ActionEvent
43  * that is received.  If the Object returned by getSource can
44  * be narrowed to a text component, it will be used.  If the
45  * action event is null or can't be narrowed, the last focused
46  * text component is tried.  This is determined by being
47  * used in conjunction with a JTextController which
48  * arranges to share that information with a TextAction.
49  * <p>
50  * <strong>Warning:</strong>
51  * Serialized objects of this class will not be compatible with
52  * future Swing releases. The current serialization support is
53  * appropriate for short term storage or RMI between applications running
54  * the same version of Swing.  As of 1.4, support for long term storage
55  * of all JavaBeans&trade;
56  * has been added to the <code>java.beans</code> package.
57  * Please see {@link java.beans.XMLEncoder}.
58  *
59  * @author  Timothy Prinzing
60  */
61 @SuppressWarnings("serial") // Same-version serialization only
62 public abstract class TextAction extends AbstractAction {
63 
64     /**
65      * Creates a new JTextAction object.
66      *
67      * @param name the name of the action
68      */
TextAction(String name)69     public TextAction(String name) {
70         super(name);
71     }
72 
73     /**
74      * Determines the component to use for the action.
75      * This if fetched from the source of the ActionEvent
76      * if it's not null and can be narrowed.  Otherwise,
77      * the last focused component is used.
78      *
79      * @param e the ActionEvent
80      * @return the component
81      */
getTextComponent(ActionEvent e)82     protected final JTextComponent getTextComponent(ActionEvent e) {
83         if (e != null) {
84             Object o = e.getSource();
85             if (o instanceof JTextComponent) {
86                 return (JTextComponent) o;
87             }
88         }
89         return getFocusedComponent();
90     }
91 
92     /**
93      * Takes one list of
94      * commands and augments it with another list
95      * of commands.  The second list takes precedence
96      * over the first list; that is, when both lists
97      * contain a command with the same name, the command
98      * from the second list is used.
99      *
100      * @param list1 the first list, may be empty but not
101      *              <code>null</code>
102      * @param list2 the second list, may be empty but not
103      *              <code>null</code>
104      * @return the augmented list
105      */
augmentList(Action[] list1, Action[] list2)106     public static final Action[] augmentList(Action[] list1, Action[] list2) {
107         Hashtable<String, Action> h = new Hashtable<String, Action>();
108         for (Action a : list1) {
109             String value = (String)a.getValue(Action.NAME);
110             h.put((value!=null ? value:""), a);
111         }
112         for (Action a : list2) {
113             String value = (String)a.getValue(Action.NAME);
114             h.put((value!=null ? value:""), a);
115         }
116         Action[] actions = new Action[h.size()];
117         int index = 0;
118         for (Enumeration<Action> e = h.elements() ; e.hasMoreElements() ;) {
119             actions[index++] = e.nextElement();
120         }
121         return actions;
122     }
123 
124     /**
125      * Fetches the text component that currently has focus.
126      * This allows actions to be shared across text components
127      * which is useful for key-bindings where a large set of
128      * actions are defined, but generally used the same way
129      * across many different components.
130      *
131      * @return the component
132      */
getFocusedComponent()133     protected final JTextComponent getFocusedComponent() {
134         return JTextComponent.getFocusedComponent();
135     }
136 }
137