java.awt.event: public class: ActionEvent

java.awt.event
public class: ActionEvent [javadoc | source]

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

All Implemented Interfaces:
Serializable

A semantic event which indicates that a component-defined action occurred. 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 ActionListener object that registered to receive such events using the component's addActionListener method.

Note: To invoke an ActionEvent on a Button using the keyboard, use the Space bar.

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".

Also see:

ActionListener

Tutorial: Java 1.1 Event Model

author: Carl - Quinn

since: 1.1 -

Field Summary
public static final int	SHIFT_MASK	The shift modifier. An indicator that the shift key was held down during the event.
public static final int	CTRL_MASK	The control modifier. An indicator that the control key was held down during the event.
public static final int	META_MASK	The meta modifier. An indicator that the meta key was held down during the event.
public static final int	ALT_MASK	The alt modifier. An indicator that the alt key was held down during the event.
public static final int	ACTION_FIRST	The first number in the range of ids used for action events.
public static final int	ACTION_LAST	The last number in the range of ids used for action events.
public static final int	ACTION_PERFORMED	This event id indicates that a meaningful action occured.
String	actionCommand	The nonlocalized string that gives more details of what actually caused the event. This information is very specific to the component that fired it. Also see: getActionCommand serial:
long	when	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. Also see: getWhen serial:
int	modifiers	This represents the key modifier that was selected, and is used to determine the state of the selected key. If no modifier has been selected it will default to zero. Also see: getModifiers serial:

Fields inherited from java.awt.AWTEvent:
id, consumed, focusManagerIsDispatching, isPosted, COMPONENT_EVENT_MASK, CONTAINER_EVENT_MASK, FOCUS_EVENT_MASK, KEY_EVENT_MASK, MOUSE_EVENT_MASK, MOUSE_MOTION_EVENT_MASK, WINDOW_EVENT_MASK, ACTION_EVENT_MASK, ADJUSTMENT_EVENT_MASK, ITEM_EVENT_MASK, TEXT_EVENT_MASK, INPUT_METHOD_EVENT_MASK, INPUT_METHODS_ENABLED_MASK, PAINT_EVENT_MASK, INVOCATION_EVENT_MASK, HIERARCHY_EVENT_MASK, HIERARCHY_BOUNDS_EVENT_MASK, MOUSE_WHEEL_EVENT_MASK, WINDOW_STATE_EVENT_MASK, WINDOW_FOCUS_EVENT_MASK, RESERVED_ID_MAX

Fields inherited from java.awt.AWTEvent:

id, consumed, focusManagerIsDispatching, isPosted, COMPONENT_EVENT_MASK, CONTAINER_EVENT_MASK, FOCUS_EVENT_MASK, KEY_EVENT_MASK, MOUSE_EVENT_MASK, MOUSE_MOTION_EVENT_MASK, WINDOW_EVENT_MASK, ACTION_EVENT_MASK, ADJUSTMENT_EVENT_MASK, ITEM_EVENT_MASK, TEXT_EVENT_MASK, INPUT_METHOD_EVENT_MASK, INPUT_METHODS_ENABLED_MASK, PAINT_EVENT_MASK, INVOCATION_EVENT_MASK, HIERARCHY_EVENT_MASK, HIERARCHY_BOUNDS_EVENT_MASK, MOUSE_WHEEL_EVENT_MASK, WINDOW_STATE_EVENT_MASK, WINDOW_FOCUS_EVENT_MASK, RESERVED_ID_MAX

Fields inherited from java.util.EventObject:
source

Constructor:

Constructor:
public ActionEvent(Object source, int id, String command) { this(source, id, command, 0); } Constructs an `ActionEvent` object. Note that passing in an invalid `id` results in unspecified behavior. This method throws an `IllegalArgumentException` if `source` is `null`. A `null` `command` string is legal, but not recommended. 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 Throws: `IllegalArgumentException` - if `source` is null
public ActionEvent(Object source, int id, String command, int modifiers) { this(source, id, command, 0, modifiers); } Constructs an `ActionEvent` object with modifier keys. Note that passing in an invalid `id` results in unspecified behavior. This method throws an `IllegalArgumentException` if `source` is `null`. A `null` `command` string is legal, but not recommended. 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 Throws: `IllegalArgumentException` - if `source` is null
public ActionEvent(Object source, int id, String command, long when, int modifiers) { super(source, id); this.actionCommand = command; this.when = when; this.modifiers = modifiers; } Constructs an `ActionEvent` object with the specified modifier keys and timestamp. Note that passing in an invalid `id` results in unspecified behavior. This method throws an `IllegalArgumentException` if `source` is `null`. A `null` `command` string is legal, but not recommended. 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 Throws: `IllegalArgumentException` - if `source` is null since: `1.4` -

 public ActionEvent(Object source,
    int id,
    String command) {
        this(source, id, command, 0);
}

ActionEvent

Note that passing in an invalid id results in unspecified behavior. This method throws an IllegalArgumentException if source is null. A null command string is legal, but not recommended.

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

Throws:

IllegalArgumentException - if source is null

 public ActionEvent(Object source,
    int id,
    String command,
    int modifiers) {
        this(source, id, command, 0, modifiers);
}

ActionEvent

Note that passing in an invalid id results in unspecified behavior. This method throws an IllegalArgumentException if source is null. A null command string is legal, but not recommended.

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

Throws:

IllegalArgumentException - if source is null

 public ActionEvent(Object source,
    int id,
    String command,
    long when,
    int modifiers) {
        super(source, id);
        this.actionCommand = command;
        this.when = when;
        this.modifiers = modifiers;
}

ActionEvent

Note that passing in an invalid id results in unspecified behavior. This method throws an IllegalArgumentException if source is null. A null command string is legal, but not recommended.

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

Throws:

IllegalArgumentException - if source is null

since: 1.4 -

Method from java.awt.event.ActionEvent Summary:
getActionCommand, getModifiers, getWhen, paramString

Methods from java.awt.AWTEvent:
consume, convertToOld, copyPrivateDataInto, dispatched, getID, isConsumed, paramString, setSource, toString

Methods from java.util.EventObject:
getSource, toString

Methods from java.lang.Object:
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from java.awt.event.ActionEvent Detail:
public String getActionCommand() { return actionCommand; } 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. Note that if a `null` command string was passed to the constructor for this `ActionEvent`, this this method returns `null`.
public int getModifiers() { return modifiers; } Returns the modifier keys held down during this action event.
public long getWhen() { return when; } 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.
public String paramString() { String typeStr; switch(id) { case ACTION_PERFORMED: typeStr = "ACTION_PERFORMED"; break; default: typeStr = "unknown type"; } return typeStr + ",cmd="+actionCommand+",when="+when+",modifiers="+ KeyEvent.getKeyModifiersText(modifiers); } Returns a parameter string identifying this action event. This method is useful for event-logging and for debugging.

Method from java.awt.event.ActionEvent Detail:

 public String getActionCommand() {
        return actionCommand;
}

Note that if a null command string was passed to the constructor for this ActionEvent, this this method returns null.

 public int getModifiers() {
        return modifiers;
}

Returns the modifier keys held down during this action event.

 public long getWhen() {
        return when;
}

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.

 public String paramString() {
        String typeStr;
        switch(id) {
          case ACTION_PERFORMED:
              typeStr = "ACTION_PERFORMED";
              break;
          default:
              typeStr = "unknown type";
        }
        return typeStr + ",cmd="+actionCommand+",when="+when+",modifiers="+
            KeyEvent.getKeyModifiersText(modifiers);
}

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