/* |
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* Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Oracle designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Oracle in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* questions. |
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*/ |
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package javax.swing; |
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import java.awt.*; |
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import java.awt.event.*; |
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import java.beans.*; |
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/** |
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* The <code>Action</code> interface provides a useful extension to the |
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* <code>ActionListener</code> |
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* interface in cases where the same functionality may be accessed by |
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* several controls. |
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* <p> |
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* In addition to the <code>actionPerformed</code> method defined by the |
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* <code>ActionListener</code> interface, this interface allows the |
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* application to define, in a single place: |
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* <ul> |
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* <li>One or more text strings that describe the function. These strings |
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* can be used, for example, to display the flyover text for a button |
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* or to set the text in a menu item. |
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* <li>One or more icons that depict the function. These icons can be used |
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* for the images in a menu control, or for composite entries in a more |
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* sophisticated user interface. |
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* <li>The enabled/disabled state of the functionality. Instead of having |
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* to separately disable the menu item and the toolbar button, the |
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* application can disable the function that implements this interface. |
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* All components which are registered as listeners for the state change |
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* then know to disable event generation for that item and to modify the |
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* display accordingly. |
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* </ul> |
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* <p> |
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* This interface can be added to an existing class or used to create an |
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* adapter (typically, by subclassing <code>AbstractAction</code>). |
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* The <code>Action</code> object |
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* can then be added to multiple <code>Action</code>-aware containers |
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* and connected to <code>Action</code>-capable |
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* components. The GUI controls can then be activated or |
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* deactivated all at once by invoking the <code>Action</code> object's |
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* <code>setEnabled</code> method. |
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* <p> |
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* Note that <code>Action</code> implementations tend to be more expensive |
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* in terms of storage than a typical <code>ActionListener</code>, |
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* which does not offer the benefits of centralized control of |
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* functionality and broadcast of property changes. For this reason, |
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* you should take care to only use <code>Action</code>s where their benefits |
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* are desired, and use simple <code>ActionListener</code>s elsewhere. |
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* <br> |
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* |
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* <h3><a name="buttonActions"></a>Swing Components Supporting <code>Action</code></h3> |
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* <p> |
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* Many of Swing's components have an <code>Action</code> property. When |
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* an <code>Action</code> is set on a component, the following things |
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* happen: |
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* <ul> |
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* <li>The <code>Action</code> is added as an <code>ActionListener</code> to |
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* the component. |
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* <li>The component configures some of its properties to match the |
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* <code>Action</code>. |
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* <li>The component installs a <code>PropertyChangeListener</code> on the |
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* <code>Action</code> so that the component can change its properties |
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* to reflect changes in the <code>Action</code>'s properties. |
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* </ul> |
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* <p> |
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* The following table describes the properties used by |
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* <code>Swing</code> components that support <code>Actions</code>. |
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* In the table, <em>button</em> refers to any |
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* <code>AbstractButton</code> subclass, which includes not only |
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* <code>JButton</code> but also classes such as |
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* <code>JMenuItem</code>. Unless otherwise stated, a |
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* <code>null</code> property value in an <code>Action</code> (or a |
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* <code>Action</code> that is <code>null</code>) results in the |
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* button's corresponding property being set to <code>null</code>. |
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* |
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* <table border="1" cellpadding="1" cellspacing="0" |
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* summary="Supported Action properties"> |
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* <tr valign="top" align="left"> |
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* <th style="background-color:#CCCCFF" align="left">Component Property |
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* <th style="background-color:#CCCCFF" align="left">Components |
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* <th style="background-color:#CCCCFF" align="left">Action Key |
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* <th style="background-color:#CCCCFF" align="left">Notes |
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* <tr valign="top" align="left"> |
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* <td><b><code>enabled</code></b> |
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* <td>All |
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* <td>The <code>isEnabled</code> method |
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* <td> |
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* <tr valign="top" align="left"> |
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* <td><b><code>toolTipText</code></b> |
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* <td>All |
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* <td><code>SHORT_DESCRIPTION</code> |
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* <td> |
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* <tr valign="top" align="left"> |
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* <td><b><code>actionCommand</code></b> |
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* <td>All |
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* <td><code>ACTION_COMMAND_KEY</code> |
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* <td> |
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* <tr valign="top" align="left"> |
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* <td><b><code>mnemonic</code></b> |
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* <td>All buttons |
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* <td><code>MNEMONIC_KEY</code> |
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* <td>A <code>null</code> value or <code>Action</code> results in the |
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* button's <code>mnemonic</code> property being set to |
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* <code>'\0'</code>. |
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* <tr valign="top" align="left"> |
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* <td><b><code>text</code></b> |
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* <td>All buttons |
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* <td><code>NAME</code> |
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* <td>If you do not want the text of the button to mirror that |
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* of the <code>Action</code>, set the property |
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* <code>hideActionText</code> to <code>true</code>. If |
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* <code>hideActionText</code> is <code>true</code>, setting the |
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* <code>Action</code> changes the text of the button to |
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* <code>null</code> and any changes to <code>NAME</code> |
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* are ignored. <code>hideActionText</code> is useful for |
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* tool bar buttons that typically only show an <code>Icon</code>. |
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* <code>JToolBar.add(Action)</code> sets the property to |
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* <code>true</code> if the <code>Action</code> has a |
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* non-<code>null</code> value for <code>LARGE_ICON_KEY</code> or |
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* <code>SMALL_ICON</code>. |
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* <tr valign="top" align="left"> |
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* <td><b><code>displayedMnemonicIndex</code></b> |
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* <td>All buttons |
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* <td><code>DISPLAYED_MNEMONIC_INDEX_KEY</code> |
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* <td>If the value of <code>DISPLAYED_MNEMONIC_INDEX_KEY</code> is |
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* beyond the bounds of the text, it is ignored. When |
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* <code>setAction</code> is called, if the value from the |
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* <code>Action</code> is <code>null</code>, the displayed |
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* mnemonic index is not updated. In any subsequent changes to |
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* <code>DISPLAYED_MNEMONIC_INDEX_KEY</code>, <code>null</code> |
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* is treated as -1. |
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* <tr valign="top" align="left"> |
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* <td><b><code>icon</code></b> |
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* <td>All buttons except of <code>JCheckBox</code>, |
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* <code>JToggleButton</code> and <code>JRadioButton</code>. |
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* <td>either <code>LARGE_ICON_KEY</code> or |
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* <code>SMALL_ICON</code> |
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* <td>The <code>JMenuItem</code> subclasses only use |
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* <code>SMALL_ICON</code>. All other buttons will use |
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* <code>LARGE_ICON_KEY</code>; if the value is <code>null</code> they |
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* use <code>SMALL_ICON</code>. |
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* <tr valign="top" align="left"> |
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* <td><b><code>accelerator</code></b> |
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* <td>All <code>JMenuItem</code> subclasses, with the exception of |
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* <code>JMenu</code>. |
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* <td><code>ACCELERATOR_KEY</code> |
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* <td> |
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* <tr valign="top" align="left"> |
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* <td><b><code>selected</code></b> |
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* <td><code>JToggleButton</code>, <code>JCheckBox</code>, |
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* <code>JRadioButton</code>, <code>JCheckBoxMenuItem</code> and |
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* <code>JRadioButtonMenuItem</code> |
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* <td><code>SELECTED_KEY</code> |
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* <td>Components that honor this property only use |
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* the value if it is {@code non-null}. For example, if |
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* you set an {@code Action} that has a {@code null} |
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* value for {@code SELECTED_KEY} on a {@code JToggleButton}, the |
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* {@code JToggleButton} will not update it's selected state in |
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* any way. Similarly, any time the {@code JToggleButton}'s |
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* selected state changes it will only set the value back on |
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* the {@code Action} if the {@code Action} has a {@code non-null} |
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* value for {@code SELECTED_KEY}. |
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* <br> |
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* Components that honor this property keep their selected state |
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* in sync with this property. When the same {@code Action} is used |
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* with multiple components, all the components keep their selected |
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* state in sync with this property. Mutually exclusive |
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* buttons, such as {@code JToggleButton}s in a {@code ButtonGroup}, |
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* force only one of the buttons to be selected. As such, do not |
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* use the same {@code Action} that defines a value for the |
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* {@code SELECTED_KEY} property with multiple mutually |
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* exclusive buttons. |
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* </table> |
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* <p> |
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* <code>JPopupMenu</code>, <code>JToolBar</code> and <code>JMenu</code> |
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* all provide convenience methods for creating a component and setting the |
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* <code>Action</code> on the corresponding component. Refer to each of |
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* these classes for more information. |
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* <p> |
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* <code>Action</code> uses <code>PropertyChangeListener</code> to |
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* inform listeners the <code>Action</code> has changed. The beans |
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* specification indicates that a <code>null</code> property name can |
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* be used to indicate multiple values have changed. By default Swing |
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* components that take an <code>Action</code> do not handle such a |
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* change. To indicate that Swing should treat <code>null</code> |
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* according to the beans specification set the system property |
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* <code>swing.actions.reconfigureOnNull</code> to the <code>String</code> |
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* value <code>true</code>. |
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* |
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* @author Georges Saab |
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* @see AbstractAction |
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*/ |
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public interface Action extends ActionListener { |
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/** |
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* Useful constants that can be used as the storage-retrieval key |
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* when setting or getting one of this object's properties (text |
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* or icon). |
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*/ |
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/** |
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* Not currently used. |
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*/ |
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public static final String DEFAULT = "Default"; |
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/** |
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* The key used for storing the <code>String</code> name |
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* for the action, used for a menu or button. |
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*/ |
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public static final String NAME = "Name"; |
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/** |
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* The key used for storing a short <code>String</code> |
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* description for the action, used for tooltip text. |
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*/ |
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public static final String SHORT_DESCRIPTION = "ShortDescription"; |
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/** |
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* The key used for storing a longer <code>String</code> |
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* description for the action, could be used for context-sensitive help. |
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*/ |
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public static final String LONG_DESCRIPTION = "LongDescription"; |
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/** |
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* The key used for storing a small <code>Icon</code>, such |
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* as <code>ImageIcon</code>. This is typically used with |
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* menus such as <code>JMenuItem</code>. |
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* <p> |
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* If the same <code>Action</code> is used with menus and buttons you'll |
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* typically specify both a <code>SMALL_ICON</code> and a |
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* <code>LARGE_ICON_KEY</code>. The menu will use the |
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* <code>SMALL_ICON</code> and the button will use the |
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* <code>LARGE_ICON_KEY</code>. |
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*/ |
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public static final String SMALL_ICON = "SmallIcon"; |
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/** |
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* The key used to determine the command <code>String</code> for the |
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* <code>ActionEvent</code> that will be created when an |
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* <code>Action</code> is going to be notified as the result of |
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* residing in a <code>Keymap</code> associated with a |
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* <code>JComponent</code>. |
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*/ |
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public static final String ACTION_COMMAND_KEY = "ActionCommandKey"; |
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/** |
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* The key used for storing a <code>KeyStroke</code> to be used as the |
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* accelerator for the action. |
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* |
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* @since 1.3 |
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*/ |
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public static final String ACCELERATOR_KEY="AcceleratorKey"; |
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/** |
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* The key used for storing an <code>Integer</code> that corresponds to |
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* one of the <code>KeyEvent</code> key codes. The value is |
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* commonly used to specify a mnemonic. For example: |
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* <code>myAction.putValue(Action.MNEMONIC_KEY, KeyEvent.VK_A)</code> |
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* sets the mnemonic of <code>myAction</code> to 'a', while |
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* <code>myAction.putValue(Action.MNEMONIC_KEY, KeyEvent.getExtendedKeyCodeForChar('\u0444'))</code> |
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* sets the mnemonic of <code>myAction</code> to Cyrillic letter "Ef". |
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* |
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* @since 1.3 |
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*/ |
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public static final String MNEMONIC_KEY="MnemonicKey"; |
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/** |
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* The key used for storing a <code>Boolean</code> that corresponds |
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* to the selected state. This is typically used only for components |
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* that have a meaningful selection state. For example, |
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* <code>JRadioButton</code> and <code>JCheckBox</code> make use of |
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* this but instances of <code>JMenu</code> don't. |
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* <p> |
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* This property differs from the others in that it is both read |
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* by the component and set by the component. For example, |
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* if an <code>Action</code> is attached to a <code>JCheckBox</code> |
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* the selected state of the <code>JCheckBox</code> will be set from |
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* that of the <code>Action</code>. If the user clicks on the |
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* <code>JCheckBox</code> the selected state of the <code>JCheckBox</code> |
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* <b>and</b> the <code>Action</code> will <b>both</b> be updated. |
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* <p> |
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* Note: the value of this field is prefixed with 'Swing' to |
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* avoid possible collisions with existing <code>Actions</code>. |
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* |
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* @since 1.6 |
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*/ |
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public static final String SELECTED_KEY = "SwingSelectedKey"; |
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/** |
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* The key used for storing an <code>Integer</code> that corresponds |
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* to the index in the text (identified by the <code>NAME</code> |
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* property) that the decoration for a mnemonic should be rendered at. If |
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* the value of this property is greater than or equal to the length of |
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* the text, it will treated as -1. |
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* <p> |
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* Note: the value of this field is prefixed with 'Swing' to |
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* avoid possible collisions with existing <code>Actions</code>. |
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* |
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* @see AbstractButton#setDisplayedMnemonicIndex |
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* @since 1.6 |
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*/ |
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public static final String DISPLAYED_MNEMONIC_INDEX_KEY = |
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"SwingDisplayedMnemonicIndexKey"; |
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/** |
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* The key used for storing an <code>Icon</code>. This is typically |
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* used by buttons, such as <code>JButton</code> and |
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* <code>JToggleButton</code>. |
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* <p> |
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* If the same <code>Action</code> is used with menus and buttons you'll |
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* typically specify both a <code>SMALL_ICON</code> and a |
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* <code>LARGE_ICON_KEY</code>. The menu will use the |
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* <code>SMALL_ICON</code> and the button the <code>LARGE_ICON_KEY</code>. |
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* <p> |
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* Note: the value of this field is prefixed with 'Swing' to |
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* avoid possible collisions with existing <code>Actions</code>. |
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* |
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* @since 1.6 |
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*/ |
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public static final String LARGE_ICON_KEY = "SwingLargeIconKey"; |
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/** |
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* Gets one of this object's properties |
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* using the associated key. |
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* @see #putValue |
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*/ |
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public Object getValue(String key); |
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/** |
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* Sets one of this object's properties |
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* using the associated key. If the value has |
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* changed, a <code>PropertyChangeEvent</code> is sent |
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* to listeners. |
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* |
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* @param key a <code>String</code> containing the key |
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* @param value an <code>Object</code> value |
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*/ |
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public void putValue(String key, Object value); |
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/** |
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* Sets the enabled state of the <code>Action</code>. When enabled, |
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* any component associated with this object is active and |
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* able to fire this object's <code>actionPerformed</code> method. |
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* If the value has changed, a <code>PropertyChangeEvent</code> is sent |
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* to listeners. |
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* |
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* @param b true to enable this <code>Action</code>, false to disable it |
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*/ |
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public void setEnabled(boolean b); |
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/** |
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* Returns the enabled state of the <code>Action</code>. When enabled, |
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* any component associated with this object is active and |
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* able to fire this object's <code>actionPerformed</code> method. |
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* |
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* @return true if this <code>Action</code> is enabled |
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*/ |
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public boolean isEnabled(); |
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/** |
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* Adds a <code>PropertyChange</code> listener. Containers and attached |
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* components use these methods to register interest in this |
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* <code>Action</code> object. When its enabled state or other property |
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* changes, the registered listeners are informed of the change. |
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* |
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* @param listener a <code>PropertyChangeListener</code> object |
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*/ |
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public void addPropertyChangeListener(PropertyChangeListener listener); |
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/** |
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* Removes a <code>PropertyChange</code> listener. |
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* |
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* @param listener a <code>PropertyChangeListener</code> object |
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* @see #addPropertyChangeListener |
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*/ |
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public void removePropertyChangeListener(PropertyChangeListener listener); |
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} |