ActionEvent

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## java.awt.event
Class ActionEvent

    java.lang.Object
      java.util.EventObject
          java.awt.AWTEvent
              java.awt.event.ActionEvent

All Implemented Interfaces:
  Serializable

Direct Known Subclasses:
  HActionEvent

    public class ActionEvent

extends AWTEvent

A semantic event which indicates that a component-defined action occured. This high-level event is generated by a component (such as a Button) when the component-specific action occurs (such as being pressed). The event is passed to every every `ActionListener` object that registered to receive such events using the component's `addActionListener` method.

The object that implements the `ActionListener` interface gets this `ActionEvent` when the event occurs. The listener is therefore spared the details of processing individual mouse movements and mouse clicks, and can instead process a "meaningful" (semantic) event like "button pressed".

Note: The timestamps used by this class report the difference, measured in milliseconds, between the time of the event and midnight, January 1, 1970 UTC (similar to `System.currentTimeMillis`).

Since:
  1.1
Version:
  1.25 01/23/03
Author:
  Carl Quinn
See Also:
  `ActionListener`, Tutorial: Java 1.1 Event Model, Reference: The Java Class Libraries (update file), Serialized Form

Field Summary
`static int` | `ACTION_FIRST` The first number in the range of ids used for action events.
`static int` | `ACTION_LAST` The last number in the range of ids used for action events.
`static int` | `ACTION_PERFORMED` This event id indicates that a meaningful action occured.
`static int` | `ALT_MASK` The alt modifier.
`static int` | `CTRL_MASK` The control modifier.
`static int` | `META_MASK` The meta modifier.
`static int` | `SHIFT_MASK` The shift modifier.

Fields inherited from class java.awt.AWTEvent
`ACTION_EVENT_MASK, ADJUSTMENT_EVENT_MASK, COMPONENT_EVENT_MASK, CONTAINER_EVENT_MASK, FOCUS_EVENT_MASK, INPUT_METHOD_EVENT_MASK, INVOCATION_EVENT_MASK, ITEM_EVENT_MASK, KEY_EVENT_MASK, MOUSE_EVENT_MASK, MOUSE_MOTION_EVENT_MASK, MOUSE_WHEEL_EVENT_MASK, PAINT_EVENT_MASK, RESERVED_ID_MAX, TEXT_EVENT_MASK, WINDOW_EVENT_MASK, WINDOW_FOCUS_EVENT_MASK`

Constructor Summary
`ActionEvent(Object source, int id, String command)` Constructs an `ActionEvent` object.
`ActionEvent(Object source, int id, String command, int modifiers)` Constructs an `ActionEvent` object with modifier keys.
`ActionEvent(Object source, int id, String command, long when, int modifiers)` Constructs an `ActionEvent` object with the specified modifier keys and timestamp.

Method Summary
`String` | `getActionCommand()` Returns the command string associated with this action.
`int` | `getModifiers()` Returns the modifier keys held down during this action event.
`long` | `getWhen()` Returns the timestamp of when this event occurred.
`String` | `paramString()` Returns a parameter string identifying this action event.

Methods inherited from class java.awt.AWTEvent
`getID, toString`

Methods inherited from class java.util.EventObject
`getSource`

Methods inherited from class java.lang.Object
`equals, getClass, hashCode, notify, notifyAll, wait, wait, wait`

Field Detail

### SHIFT_MASK

    public static final int SHIFT_MASK

  The shift modifier. An indicator that the shift key was held down during the event.

  See Also:
    Constant Field Values

### CTRL_MASK

    public static final int CTRL_MASK

  The control modifier. An indicator that the control key was held down during the event.

  See Also:
    Constant Field Values

### META_MASK

    public static final int META_MASK

  The meta modifier. An indicator that the meta key was held down during the event.

  See Also:
    Constant Field Values

### ALT_MASK

    public static final int ALT_MASK

  The alt modifier. An indicator that the alt key was held down during the event.

  See Also:
    Constant Field Values

### ACTION_FIRST

    public static final int ACTION_FIRST

  The first number in the range of ids used for action events.

  See Also:
    Constant Field Values

### ACTION_LAST

    public static final int ACTION_LAST

  The last number in the range of ids used for action events.

  See Also:
    Constant Field Values

### ACTION_PERFORMED

    public static final int ACTION_PERFORMED

  This event id indicates that a meaningful action occured.

  See Also:
    Constant Field Values

Constructor Detail

### ActionEvent

    public ActionEvent(Object source,
                       int id,
                       String command)

  Constructs an `ActionEvent` object.

  Note that passing in an invalid `id` results in unspecified behavior.

  Parameters:
    `source` - the object that originated the event
    `id` - an integer that identifies the event
    `command` - a string that may specify a command (possibly one of several) associated with the event

### ActionEvent

    public ActionEvent(Object source,
                       int id,
                       String command,
                       int modifiers)

  Constructs an `ActionEvent` object with modifier keys.

  Note that passing in an invalid `id` results in unspecified behavior.

  Parameters:
    `source` - the object that originated the event
    `id` - an integer that identifies the event
    `command` - a string that may specify a command (possibly one of several) associated with the event
    `modifiers` - the modifier keys held down during this action

### ActionEvent

    public ActionEvent(Object source,
                       int id,
                       String command,
                       long when,
                       int modifiers)

  Constructs an `ActionEvent` object with the specified modifier keys and timestamp.

  Note that passing in an invalid `id` results in unspecified behavior.

  Parameters:
    `source` - the object that originated the event
    `id` - an integer that identifies the event
    `command` - a string that may specify a command (possibly one of several) associated with the event
    `when` - the time the event occurred
    `modifiers` - the modifier keys held down during this action
  Since:
    1.4

Method Detail

### getActionCommand

    public String getActionCommand()

  Returns the command string associated with this action. This string allows a "modal" component to specify one of several commands, depending on its state. For example, a single button might toggle between "show details" and "hide details". The source object and the event would be the same in each case, but the command string would identify the intended action.

  Returns:
    the string identifying the command for this event

### getWhen

    public long getWhen()

  Returns the timestamp of when this event occurred. Because an ActionEvent is a high-level, semantic event, the timestamp is typically the same as an underlying InputEvent.

  Returns:
    this event's timestamp
  Since:
    1.4

### getModifiers

    public int getModifiers()

  Returns the modifier keys held down during this action event.

  Returns:
    the bitwise-or of the modifier constants

### paramString

    public String paramString()

  Returns a parameter string identifying this action event. This method is useful for event-logging and for debugging.

  Overrides:
    `paramString` in class `AWTEvent`
  Returns:
    a string identifying the event and its associated command

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