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