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package javax.swing;

import java.awt.*;
import java.awt.event.*;
import java.beans.*;

/**
 * The <code>Action</code> interface provides a useful extension to the
 * <code>ActionListener</code>
 * interface in cases where the same functionality may be accessed by
 * several controls.
 * <p>
 * In addition to the <code>actionPerformed</code> method defined by the
 * <code>ActionListener</code> 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</code>).
 * The <code>Action</code> object
 * can then be added to multiple <code>Action</code>-aware containers
 * and connected to <code>Action</code>-capable
 * components. The GUI controls can then be activated or
 * deactivated all at once by invoking the <code>Action</code> object's
 * <code>setEnabled</code> method.
 * <p>
 * Note that <code>Action</code> implementations tend to be more expensive
 * in terms of storage than a typical <code>ActionListener</code>,
 * 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>Action</code>s where their benefits
 * are desired, and use simple <code>ActionListener</code>s elsewhere.
 * <br>
 *
 * <h3><a name="buttonActions"></a>Swing Components Supporting <code>Action</code></h3>
 * <p>
 * Many of Swing's components have an <code>Action</code> property. When
 * an <code>Action</code> is set on a component, the following things
 * happen:
 * <ul>
 * <li>The <code>Action</code> is added as an <code>ActionListener</code> to
 * the component.
 * <li>The component configures some of its properties to match the
 * <code>Action</code>.
 * <li>The component installs a <code>PropertyChangeListener</code> on the
 * <code>Action</code> so that the component can change its properties
 * to reflect changes in the <code>Action</code>'s properties.
 * </ul>
 * <p>
 * The following table describes the properties used by
 * <code>Swing</code> components that support <code>Actions</code>.
 * In the table, <em>button</em> refers to any
 * <code>AbstractButton</code> subclass, which includes not only
 * <code>JButton</code> but also classes such as
 * <code>JMenuItem</code>. Unless otherwise stated, a
 * <code>null</code> property value in an <code>Action</code> (or a
 * <code>Action</code> that is <code>null</code>) results in the
 * button's corresponding property being set to <code>null</code>.
 *
 * <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><b><code>enabled</code></b>
 * <td>All
 * <td>The <code>isEnabled</code> method
 * <td>&nbsp;
 * <tr valign="top" align="left">
 * <td><b><code>toolTipText</code></b>
 * <td>All
 * <td><code>SHORT_DESCRIPTION</code>
 * <td>&nbsp;
 * <tr valign="top" align="left">
 * <td><b><code>actionCommand</code></b>
 * <td>All
 * <td><code>ACTION_COMMAND_KEY</code>
 * <td>&nbsp;
 * <tr valign="top" align="left">
 * <td><b><code>mnemonic</code></b>
 * <td>All buttons
 * <td><code>MNEMONIC_KEY</code>
 * <td>A <code>null</code> value or <code>Action</code> results in the
 * button's <code>mnemonic</code> property being set to
 * <code>'0円'</code>.
 * <tr valign="top" align="left">
 * <td><b><code>text</code></b>
 * <td>All buttons
 * <td><code>NAME</code>
 * <td>If you do not want the text of the button to mirror that
 * of the <code>Action</code>, set the property
 * <code>hideActionText</code> to <code>true</code>. If
 * <code>hideActionText</code> is <code>true</code>, setting the
 * <code>Action</code> changes the text of the button to
 * <code>null</code> and any changes to <code>NAME</code>
 * are ignored. <code>hideActionText</code> is useful for
 * tool bar buttons that typically only show an <code>Icon</code>.
 * <code>JToolBar.add(Action)</code> sets the property to
 * <code>true</code> if the <code>Action</code> has a
 * non-<code>null</code> value for <code>LARGE_ICON_KEY</code> or
 * <code>SMALL_ICON</code>.
 * <tr valign="top" align="left">
 * <td><b><code>displayedMnemonicIndex</code></b>
 * <td>All buttons
 * <td><code>DISPLAYED_MNEMONIC_INDEX_KEY</code>
 * <td>If the value of <code>DISPLAYED_MNEMONIC_INDEX_KEY</code> is
 * beyond the bounds of the text, it is ignored. When
 * <code>setAction</code> is called, if the value from the
 * <code>Action</code> is <code>null</code>, the displayed
 * mnemonic index is not updated. In any subsequent changes to
 * <code>DISPLAYED_MNEMONIC_INDEX_KEY</code>, <code>null</code>
 * is treated as -1.
 * <tr valign="top" align="left">
 * <td><b><code>icon</code></b>
 * <td>All buttons except of <code>JCheckBox</code>,
 * <code>JToggleButton</code> and <code>JRadioButton</code>.
 * <td>either <code>LARGE_ICON_KEY</code> or
 * <code>SMALL_ICON</code>
 * <td>The <code>JMenuItem</code> subclasses only use
 * <code>SMALL_ICON</code>. All other buttons will use
 * <code>LARGE_ICON_KEY</code>; if the value is <code>null</code> they
 * use <code>SMALL_ICON</code>.
 * <tr valign="top" align="left">
 * <td><b><code>accelerator</code></b>
 * <td>All <code>JMenuItem</code> subclasses, with the exception of
 * <code>JMenu</code>.
 * <td><code>ACCELERATOR_KEY</code>
 * <td>&nbsp;
 * <tr valign="top" align="left">
 * <td><b><code>selected</code></b>
 * <td><code>JToggleButton</code>, <code>JCheckBox</code>,
 * <code>JRadioButton</code>, <code>JCheckBoxMenuItem</code> and
 * <code>JRadioButtonMenuItem</code>
 * <td><code>SELECTED_KEY</code>
 * <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</code>, <code>JToolBar</code> and <code>JMenu</code>
 * all provide convenience methods for creating a component and setting the
 * <code>Action</code> on the corresponding component. Refer to each of
 * these classes for more information.
 * <p>
 * <code>Action</code> uses <code>PropertyChangeListener</code> to
 * inform listeners the <code>Action</code> has changed. The beans
 * specification indicates that a <code>null</code> property name can
 * be used to indicate multiple values have changed. By default Swing
 * components that take an <code>Action</code> do not handle such a
 * change. To indicate that Swing should treat <code>null</code>
 * according to the beans specification set the system property
 * <code>swing.actions.reconfigureOnNull</code> to the <code>String</code>
 * value <code>true</code>.
 *
 * @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</code> 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</code>
 * description for the action, used for tooltip text.
 */
 public static final String SHORT_DESCRIPTION = "ShortDescription";
 /**
 * The key used for storing a longer <code>String</code>
 * 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</code>, such
 * as <code>ImageIcon</code>. This is typically used with
 * menus such as <code>JMenuItem</code>.
 * <p>
 * If the same <code>Action</code> is used with menus and buttons you'll
 * typically specify both a <code>SMALL_ICON</code> and a
 * <code>LARGE_ICON_KEY</code>. The menu will use the
 * <code>SMALL_ICON</code> and the button will use the
 * <code>LARGE_ICON_KEY</code>.
 */
 public static final String SMALL_ICON = "SmallIcon";

 /**
 * The key used to determine the command <code>String</code> for the
 * <code>ActionEvent</code> that will be created when an
 * <code>Action</code> is going to be notified as the result of
 * residing in a <code>Keymap</code> associated with a
 * <code>JComponent</code>.
 */
 public static final String ACTION_COMMAND_KEY = "ActionCommandKey";

 /**
 * The key used for storing a <code>KeyStroke</code> 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</code> that corresponds to
 * one of the <code>KeyEvent</code> key codes. The value is
 * commonly used to specify a mnemonic. For example:
 * <code>myAction.putValue(Action.MNEMONIC_KEY, KeyEvent.VK_A)</code>
 * sets the mnemonic of <code>myAction</code> to 'a', while
 * <code>myAction.putValue(Action.MNEMONIC_KEY, KeyEvent.getExtendedKeyCodeForChar('\u0444'))</code>
 * sets the mnemonic of <code>myAction</code> to Cyrillic letter "Ef".
 *
 * @since 1.3
 */
 public static final String MNEMONIC_KEY="MnemonicKey";

 /**
 * The key used for storing a <code>Boolean</code> that corresponds
 * to the selected state. This is typically used only for components
 * that have a meaningful selection state. For example,
 * <code>JRadioButton</code> and <code>JCheckBox</code> make use of
 * this but instances of <code>JMenu</code> 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</code> is attached to a <code>JCheckBox</code>
 * the selected state of the <code>JCheckBox</code> will be set from
 * that of the <code>Action</code>. If the user clicks on the
 * <code>JCheckBox</code> the selected state of the <code>JCheckBox</code>
 * <b>and</b> the <code>Action</code> will <b>both</b> be updated.
 * <p>
 * Note: the value of this field is prefixed with 'Swing' to
 * avoid possible collisions with existing <code>Actions</code>.
 *
 * @since 1.6
 */
 public static final String SELECTED_KEY = "SwingSelectedKey";

 /**
 * The key used for storing an <code>Integer</code> that corresponds
 * to the index in the text (identified by the <code>NAME</code>
 * 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</code>.
 *
 * @see AbstractButton#setDisplayedMnemonicIndex
 * @since 1.6
 */
 public static final String DISPLAYED_MNEMONIC_INDEX_KEY =
 "SwingDisplayedMnemonicIndexKey";

 /**
 * The key used for storing an <code>Icon</code>. This is typically
 * used by buttons, such as <code>JButton</code> and
 * <code>JToggleButton</code>.
 * <p>
 * If the same <code>Action</code> is used with menus and buttons you'll
 * typically specify both a <code>SMALL_ICON</code> and a
 * <code>LARGE_ICON_KEY</code>. The menu will use the
 * <code>SMALL_ICON</code> and the button the <code>LARGE_ICON_KEY</code>.
 * <p>
 * Note: the value of this field is prefixed with 'Swing' to
 * avoid possible collisions with existing <code>Actions</code>.
 *
 * @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</code> is sent
 * to listeners.
 *
 * @param key a <code>String</code> containing the key
 * @param value an <code>Object</code> value
 */
 public void putValue(String key, Object value);

 /**
 * Sets the enabled state of the <code>Action</code>. When enabled,
 * any component associated with this object is active and
 * able to fire this object's <code>actionPerformed</code> method.
 * If the value has changed, a <code>PropertyChangeEvent</code> is sent
 * to listeners.
 *
 * @param b true to enable this <code>Action</code>, false to disable it
 */
 public void setEnabled(boolean b);
 /**
 * Returns the enabled state of the <code>Action</code>. When enabled,
 * any component associated with this object is active and
 * able to fire this object's <code>actionPerformed</code> method.
 *
 * @return true if this <code>Action</code> is enabled
 */
 public boolean isEnabled();

 /**
 * Adds a <code>PropertyChange</code> listener. Containers and attached
 * components use these methods to register interest in this
 * <code>Action</code> object. When its enabled state or other property
 * changes, the registered listeners are informed of the change.
 *
 * @param listener a <code>PropertyChangeListener</code> object
 */
 public void addPropertyChangeListener(PropertyChangeListener listener);
 /**
 * Removes a <code>PropertyChange</code> listener.
 *
 * @param listener a <code>PropertyChangeListener</code> object
 * @see #addPropertyChangeListener
 */
 public void removePropertyChangeListener(PropertyChangeListener listener);

}