/*
* @(#)ActionEvent.java 1.29 04/01/28
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.awt.event;
import java.awt.AWTEvent;
import java.awt.Event;
/**
* A semantic event which indicates that a component-defined action occurred.
* This high-level event is generated by a component (such as a
* <code>Button</code>) when
* the component-specific action occurs (such as being pressed).
* The event is passed to every every <code>ActionListener</code> object
* that registered to receive such events using the component's
* <code>addActionListener</code> method.
* <p>
* <b>Note:</b> To invoke an <code>ActionEvent</code> on a
* <code>Button</code> using the keyboard, use the Space bar.
* <P>
* The object that implements the <code>ActionListener</code> interface
* gets this <code>ActionEvent</code> 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".
*
* @see ActionListener
* @see <a href="http://java.sun.com/docs/books/tutorial/post1.0/ui/eventmodel.html">Tutorial: Java 1.1 Event Model</a>
* @see <a href="http://www.awl.com/cp/javaseries/jcl1_2.html">Reference: The Java Class Libraries (update file)</a>
*
* @author Carl Quinn
* @version 1.29 01/28/04
* @since 1.1
*/
public class ActionEvent extends AWTEvent {
/**
* The shift modifier. An indicator that the shift key was held
* down during the event.
*/
public static final int SHIFT_MASK = Event.SHIFT_MASK;
/**
* The control modifier. An indicator that the control key was held
* down during the event.
*/
public static final int CTRL_MASK = Event.CTRL_MASK;
/**
* The meta modifier. An indicator that the meta key was held
* down during the event.
*/
public static final int META_MASK = Event.META_MASK;
/**
* The alt modifier. An indicator that the alt key was held
* down during the event.
*/
public static final int ALT_MASK = Event.ALT_MASK;
/**
* The first number in the range of ids used for action events.
*/
public static final int ACTION_FIRST = 1001;
/**
* The last number in the range of ids used for action events.
*/
public static final int ACTION_LAST = 1001;
/**
* This event id indicates that a meaningful action occured.
*/
public static final int ACTION_PERFORMED = ACTION_FIRST; //Event.ACTION_EVENT
/**
* The nonlocalized string that gives more details
* of what actually caused the event.
* This information is very specific to the component
* that fired it.
* @serial
* @see #getActionCommand
*/
String actionCommand;
/**
* 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.
*
* @serial
* @see #getWhen
*/
long when;
/**
* 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.
*
* @serial
* @see #getModifiers
*/
int modifiers;
/*
* JDK 1.1 serialVersionUID
*/
private static final long serialVersionUID = -7671078796273832149L;
/**
* Constructs an <code>ActionEvent</code> object.
* <p>
* Note that passing in an invalid <code>id</code> results in
* unspecified behavior. This method throws an
* <code>IllegalArgumentException</code> if <code>source</code>
* is <code>null</code>.
* A <code>null</code> <code>command</code> string is legal,
* but not recommended.
*
* @param source the object that originated the event
* @param id an integer that identifies the event
* @param command a string that may specify a command (possibly one
* of several) associated with the event
* @throws IllegalArgumentException if <code>source</code> is null
*/
public ActionEvent(Object source, int id, String command) {
this(source, id, command, 0);
}
/**
* Constructs an <code>ActionEvent</code> object with modifier keys.
* <p>
* Note that passing in an invalid <code>id</code> results in
* unspecified behavior. This method throws an
* <code>IllegalArgumentException</code> if <code>source</code>
* is <code>null</code>.
* A <code>null</code> <code>command</code> string is legal,
* but not recommended.
*
* @param source the object that originated the event
* @param id an integer that identifies the event
* @param command a string that may specify a command (possibly one
* of several) associated with the event
* @param modifiers the modifier keys held down during this action
* @throws IllegalArgumentException if <code>source</code> is null
*/
public ActionEvent(Object source, int id, String command, int modifiers) {
this(source, id, command, 0, modifiers);
}
/**
* Constructs an <code>ActionEvent</code> object with the specified
* modifier keys and timestamp.
* <p>
* Note that passing in an invalid <code>id</code> results in
* unspecified behavior. This method throws an
* <code>IllegalArgumentException</code> if <code>source</code>
* is <code>null</code>.
* A <code>null</code> <code>command</code> string is legal,
* but not recommended.
*
* @param source the object that originated the event
* @param id an integer that identifies the event
* @param command a string that may specify a command (possibly one
* of several) associated with the event
* @param when the time the event occurred
* @param modifiers the modifier keys held down during this action
* @throws IllegalArgumentException if <code>source</code> is null
*
* @since 1.4
*/
public ActionEvent(Object source, int id, String command, long when,
int modifiers) {
super(source, id);
this.actionCommand = command;
this.when = when;
this.modifiers = modifiers;
}
/**
* 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.
* <p>
* Note that if a <code>null</code> command string was passed
* to the constructor for this <code>ActionEvent</code>, this
* this method returns <code>null</code>.
*
* @return the string identifying the command for this event
*/
public String getActionCommand() {
return actionCommand;
}
/**
* 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.
*
* @return this event's timestamp
* @since 1.4
*/
public long getWhen() {
return when;
}
/**
* Returns the modifier keys held down during this action event.
*
* @return the bitwise-or of the modifier constants
*/
public int getModifiers() {
return modifiers;
}
/**
* Returns a parameter string identifying this action event.
* This method is useful for event-logging and for debugging.
*
* @return a string identifying the event and its associated command
*/
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);
}
}
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